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General Rules about Physician-Patient Relationships

General Rules about Physician-Patient Relationships
1.Patient is number one
2.Always respond to the patient
3.Tell the patient everything, even if he or she doesn’t ask
4.Work on developing a rapport on an ongoing basis
5.Listen, reflect, encourage
6.Negotiate, rather than order
7.Trust must be built, not assumed
8.Admit to the patient when you make a mistake
9.Never “pass off” your patient to someone else
10.Express empathy, then give control
11.Agree on problem before moving to solution
12.Be sure you understand what the patient is talking about before intervening
13.Patients do not get to select inappropriate treatments
14.Be sure who your patient is
15.Never lie
16.Accept the health benefits of patients
17.Accept patient’s religious beliefs and participate if possible
18.Anything that increases communication is good
19.Be an advocate for the patient
20.The key is not so much what you do, but how you do it

The key is not what physicians actually do, but what the most ideal physician should do.

Ethical and Legal Issues
1.Competent patients have the right to refuse medical treatment
2.Assume that the person is competent unless clear behavioral evidence indicates otherwise
3.Decision-making should occur in clinical setting if possible, without going to court
4.When surrogates make decisions for a patient, they should use the following criteria and in this order:
a.Subjective standard
b.Substituted judgment
c.Best interest standards
5.If patient is incompetent, physician may rely on advance directives
6.Feeding tube is a medical treatment and can be withdrawn at the patient’s request
7.Do nothing to actively assist the patient to die sooner
8.The physician decides when the patient is dead
9.Never abandon a patient
10.Always obtain informed consent (exceptions)
11.Special rules apply with children
12.Parents cannot withhold life- or limb- saving treatment from their child
13.For the purpose of the USMLE, issues governed by laws that vary widely across states cannot be tested
14.Good Samaritan Laws limit liability when physicians help at accidents
15.Confidentiality is absolute
16.Patients should be given the chance to state DNR orders, and physicians should follow them
17.Committed mentally ill patients retain their rights
18.Detain patients to protect them or others
19.Remove from patient contact health care professionals who pose risk to patients
20.Focus on what is the best ethical conduct, not simply the letter of the law

Pharyngeal Arches


·muscles of mastication
·tensor tympani
·maxilla and mandible
·malleus, incus

·muscles of facial expression
·lesser horn and upper body of hyoid
·both common carotid artery
·both internal carotid arteries
·stylopharyngeus muscle
·greater horn and lower body of hyoid bone
X (sup. laryngeal nerve)
right subclavian artery
cricothyroid muscle
laryngeal cartilages
right and left pulmonary arteries
intrinsic muscles of larynx (except cricothyroid)
laryngeal cartilages

Pharyngeal pouch
Adult derivatives
Epithelial lining of auditory tube and middle ear cavity
Epithelial lining of crypts of palatine tonsil
Inferior parathyroid gland
Superior parathyroid gland
Ultimobranchial body

Neural crest cells migrate into the ultimobranchial body to form parafollicular (C) cells of the thyroid .

Clinically important Oncogenes
Gene Product
Mechanism of activation
Growth Factors
hst-1 & int-2
cancer of stomach, breast, bladder, and melanoma
Fibroblast growth factor
Over expression
Platelet derived growth factor

Growth factor receptors

SCC of lung
Breast, ovary, lung
Epidermal growth factor receptor
Over expression
MEN II & III, familial thyroid (medullary) cancer
Glial neurotrophic factor receptor
Point mutation

Signal transduction proteins

bcr-abl fusion protein with tyrosine kinase activity
Translocation t(9;22)
Lung, pancreas and colon
GTP binding protein
Point mutation
Burkitt’s lymphoma
Lung carcinoma (small cell)
Nuclear regulatory protein
t(8;14), t(2;8), t(8;22)

Cell cycle regulatory proteins

cyclin D
Mantle cell lymphoma
Cyclic protein
Melanoma, GBM
Cyclic dependent kinase

small non-cleaved lymphocytic lymphoma
Follicular lymphoma (B cell); small cleaved cell type
a nuclear factor whose expression correlates with a neoplasm’s rate of growth and therefore with prognosis

Clinically important Tumor Suppressor Genes
von Hippel-Lindau disease, renal cell carcinoma
Wilm’s tumor
Retinoblastoma, osteosarcoma
Lung, breast, colon, etc.
p53 (Li-Fraumini syndrome)
Hereditary breast and ovary cancer
Neurofibromatosis type 1
Acoustic neuromas (neurofibromatosis type 2) , meningiomas
Adenomatous polyps and colon cancer
Colon cancer, Gastric carcinoma
Pancreatic cancer
18q (compare location of DCC gene)
p16 /(CDK4 protooncogene)

Chromosomes n diseases
del 1p

alveolar rhabdomyosarcoma


Huntington’s disease
gain of fn mutation on FGFR 3 gene
trinucleotide repeat
4, 16

del (5p)

t(4;11), t(12;21)
ALL & undifferentiated leukemia
found in subtypes of AML with basophilia (M1, M2, M4)
M2 leukemia

Cystic fibrosis

7, 17
Osteogenesis imperfecta

Sickle cell anemia
mutation in β globin gene
Ewing’s sarcoma

small non cleaved lymphocytic lymphoma, myeloma and some mantle cell lymphomas
clear cell sarcoma, also known as malignant melanoma of soft parts
Wilson’s disease


Prader-Willi syndrome
Angelman syndrome
genomic imprinting
del (16)
α thalassemia
del of one or more α globin genes
del (22)
Di George’s syndrome

Muscular Dystrophies
X chromosome
Duchenne muscular dystrophy
X linked recessive
early involvement of hip muscles
Fascioscapulohumeral dystrophy
early involvement of facial muscles including jaw
Infantile hypotonia

Myotonic dystrophy
AD early involvement of ankle & wrist
Acute progranulocytic leukemia (M3)
ass. with DIC
synovial sarcoma

Trinucleotide repeat expansions
  • Fragile X syndrome
  • Huntington’s disease
  • Friedrich’s ataxia
  • Myotonic dystrophy
  • Spinobulbar atrophy

Tumor Markers

Tumor Marker
Cancer Association
α-Fetoprotein (AFP)
Hepatocellular carcinoma, Testicular / ovarian cancer, germ cell tumors
α1-Antitrypsin (AAT)
Hepatocellular carcinoma; yolk sac or endodermal sinus tms of testis or ovary
β hCG
Hydatidiform mole, choriocarcinomas, GTT
Multiple myeloma
Small cell carcinoma of lung, neuroblastoma
Breast cancer
Pancreatic cancer
Ovarian cancer
Carcinoembryonic antigen (CEA)
(any tm. derived from gut epithelium) Colorectal, pancreatic; breast and small cell carcinoma of lung
Lactate dehydrogenase (LDH)
Hodgkin’s disease, cystic teratoma
Neuron-specific enolase (NSE)
Small cell carcinoma of lung, neuroblastoma
Prostate-specific antigen (PSA)
Prostate adenocarcinoma
melanoma, neural tms., astrocytomas

Interleukins (Cytokines)

  • Produced by macrophages (also produce IL6, IL8 & TNFα)
  • Stimulates IL-2 secretion
  • Pyrogenic
  • originally called T cell growth factor
  • Produced by activated Th 1, natural killer (NK) cells, and Tc
  • Stimulates B cells / cell division
  • Secreted by activated T cells
  • Stimulates bone marrow stem cells. (CSF; colony stimulating factors)
  • Secreted by Th2 cells and mast cells (involved in Type I Hypersensitivity reaction)
  • Stimulates B cells
  • Increases IgG and IgE
  • Secreted by Th2 cells
  • Promotes B-cell proliferation
  • Increases IgA synthesis and eosinophils
  • Stimulates production of acute-phase proteins
  • Stimulates B cells
  • Stimulates pre-B and pre-T cells
  • Produced by macrophages
  • Stimulates chemotaxis & adhesion of neutrophils
  • Down regulates cell-mediated immunity (↓CMI)
  • Inhibits cytokine release from macrophages
  • Increase platelet formation – used in thrombocytopenia
  • Activates NK cells
  • Induces Th0 to Th1
  • Increases numbers of cytotoxic T lymphocyte and delayed-type hypersensitivity cells
  • Produced by cytotoxic cells & macrophages
  • Increases MHC class I expression
  • Increases inflammatory processes
  • Produced by cytotoxic T cells
  • Increases MHC class I expression
  • Increases inflammatory processes
Interferon- α
  • used in Hepatitis B and C, leukemia, melanoma
  • Produced by a wide variety of cell types (i.e. fibroblasts) and is a potent inhibitor of viral replication.
  • used in Multiple sclerosis
  • Stimulates macrophages & NK cells
  • Inhibits Th2 cells
  • Produced by Th1 cells
  • used in Chronic granulomatous disease - ↑ TNF

CD Markers

  • Ag histocytes (Langerhan cells)
  • All T cells
  • All T cells (Signal transduction molecule)
  • T helper cell, MHC II
  • Cytotoxic T cell, MHC I
  • Leukemia (KALL Ag)
  • Marker for macrophages
CD-16 & 56
  • Marker for NK cells (CD 16 ass. with ADCC)
  • Marker for B cell (used clinically to enumerate B cell in blood; Signal transduction molecule)
  • Marker for B cell
  • B cell marker, Complement receptor, receptor for EBV
  • Helper T cell and most CD8+ T cell ; co-stimulant molecule (B7)
  • expressed by Reed-Sternberg cells and its variants (also express CD-15)
  • Required for class switch signal from T cell
  • expressed on most type of T cells, granulocytes and plasma cells, but not on normal B cells
  • NHL
HLA Markers

  • primary hemochromatosis
HLA-B13 & B17
  • psoriasis
(HLA-B12 is ass. with a decreased incidence of psoriasis)
  • psoriatic arthritis, ankylosing spondylitis, inflammatory bowel disease, Reiter’s syndrome
  • Yersinia enterocolitica ass. reactive arthritis
  • SLE (also ass. with HLA-DR3)
  • hay fever
  • multiple sclerosis
  • narcolepsy
  • Type 1 diabetes (also ass. with HLA-DR4)
  • Goodpasture’s syndrome
  • celiac sprue (also ass. with HLA-B8)
  • rheumatoid arthritis
  • persistent arthritis (eg ass. with Lyme’s disease)
  • pemphigus vulgaris
  • pernicious anemia
  • juvenile RA
  • steroid responsive nephritic syndrome

Serum Markers (autantibodies)

anti -DNA topoisomerase 1 (anti-Scl-70)
  • Diffuse systemic sclerosis (scleroderma)
anti -centromere
  • CREST syndrome (a more restricted variant of systemic sclerosis ; 10% of patients will have anti-topoisomerase ab as well )
anti -ds DNA
anti -Sm (Smith antigen)
anti -phospholipid
  • SLE
    • anti-dsDNA: prognostic significance
    • anti-Sm: specific for SLE
anti -IgG (RF)
  • Rheumatoid arthritis
  • Mixed connective tissue disease
anti -SS-A / B
  • Sjogren’s syndrome (may also be seen in SLE)
anti -smooth muscle
anti –liver/kidney/microsome
  • Autoimmune hepatitis
anti -histones
  • Drug induced lupus (procainamide, INH, hydralazine)
anti -mitochondrial
  • Primary biliary cirrhosis
anti-thyroglobulin /microsomal
  • Hashimoto’s thyroiditis

Special media for selected organisms

Regan-Lowe or Bordet-Gengou media
Campy medium or Skirrow’s agar (S)
Loffler’s coagulated serum medium (S)
Tellurite agar (D)
Enteric bacteria
Eosin methylene blue (D)
MacConkeys (D)
Enteric pathogens
Hektoen enteric agar (D)
Xylose-lysine-deoxycholate agar
Vibrio cholerae (likes alkaline growth medium)
TCBS (Thiosulfate Citrate Bile salts Sucrose agar) (S)
Charcoal-yeast extract agar (CYE agar) (S)
Lowenstein-Jensen medium (S)
Eaton’s media (“fried egg colonies”)
Neisseria from normally sterile sites, Haemophilus
Chocolate agar
Neisseria from sites with normal flora
Thayer-Martin selective medium* (S)
*Thayer-Martin media is a chocolate agar supplemented with vancomycin, nystatin and colistin to inhibit the normal flora, including non-pathogenic Neisseria

Miscellaneous Growth Requirements

Cholesterol and purines and pyrimidines
Francisella, Legionella, Brucella, Pasteurella
X (protoporphyrine) and V (NAD)
supplied by Staph. aureus (satellite phenomenon)
Haemophilus (influenzae and aegypticus require both)
*The four sisters Ella and Cysteine Chapel

Genetic Inheritance

Autosomal dominant
Autosomal recessive
X-linked recessive
·Mitral valve prolapse
·Peutz – Jegher’s syndrome
·Familial polyposis syndrome (Gardener’s syndrome)
·Gilbert syndrome
·Huntingtons chorea
·Von-Willebrand disease
·Ehlers Danlos syndrome
·Familial hypercholesterolemia
·Neurofibromatosis Type 1
·Marfans syndrome
·Acute intermittent porphyria
·Polycystic Kidney disease
·Myotonic dystrophy
·Turcot’s syndrome
·Dubin Johnson syndrome
·Rotor’s syndrome
·Wilson’s disease
·α1 antitrypsin deficiency
·Cystic fibrosis
·Hereditary factor XIII def.
·Sickle cell anemia
·Tay sachs disease
·Adenosine deaminase def.
·Xeroderma pigmentosum
·Ataxia telengiectasia
·G6PD deficiency
·Color blindness
·Hemophilia A and B
·Duchenne’s muscular dystrophy
·Lesch nyhan syndrome
·Menke’s disease
·Hunter syndrome
·Wiskot Aldrich syndrome
·Diabetes Insipidus

X-linked dominant
·Hypophosphotemic rickets
·Fragile X syndrome
Mitochondrial inheritance
·Lebers hereditary optic neuropathy
·Myoclonic epilepsy with ragged red muscle fibers

Enzyme inducers and inhibitors

Ethanol (Chronic)
Valproic acid
Macrolides (Erythromycin)
Azole antifungals
Ethanol (Acute)
HIV protease inhibitors

Pemphigus vulgaris
Bullous pemphigoid
Abs to intercellular junctions of epidermal cells
Abs to Epidermal basement membrane proteins
IgG autoantibody activity common to both
associated with chronic, severe bullae formation on the skin and oral mucosa
Mucosal lesions are extremely rare
poor prognosis, most will die within one year
good prognosis, lesions tend to heal and the patients do very well
vesicles mostly contain rounded acantholytic keratinocytes "floating" within.
Eosinophils within blisters
positive Nikolsky's sign due to the IgG-mediated destruction of intercellular bridges between keratinocytes.
negative Nikolsky's sign

Drugs causing Phototoxicity
Drugs that ↑ Q-T interval / Torsades
Fluoroquinolones esp. Sparfloxacin
K+ channel blockers (Bretylium, Amiodarone, Sotalol)
Cisapride, Erythromycin, Thioridazine, TCAs

·Magnesium has possible use as antiarrhythmics in torsades.
·A widely patent foramen ovale may allow emboli originating from the veins in the legs to bypass the pulmonary circulation and reach the systemic arteries, thereby producing infarcts (paradoxical embolism) in the brain as well as in other organs. Interatrial or interventricular defects can have the same effect.
·Triad of memory loss, urinary incontinence, and gait abnormalities is characteristic of normal pressure hydrocephalus (recently renamed intermittently raised pressure hydrocephalus)
·The most characteristic histopathologic hallmark of diffuse alveolar damage (ARDS) is formation of hyaline membranes within the alveolar cavities. These consist of proteinaceous material of plasma origin and necrotic debris from desquamated epithelium
·EDTA is administered as the Na2CaEDTA salt to avoid hypocalcaemia
·Hashimoto's disease (autoimmune thyroiditis) confers a 60- to-80 fold increased risk of developing thyroid lymphoma compared to normal controls
·Mitral valve prolapse and aortic root dilatation, which may appear in late adolescence or adulthood, are among the most serious complications of Fragile X Syndrome
·Alzheimer's disease patients are prone to large "lobar" hemorrhages that are usually centered in the parietal lobe and may spread to totally destroy an entire cerebral hemisphere, resulting in death. This is due to amyloid deposition into the walls of cerebral blood vessels (amyloid angiopathy), similar to the amyloid plaques seen in the parenchyma of the brain with this disease. Amyloid makes these vessels weak and prone to rupture
·PAS-positive cytoplasmic granules are a feature of alpha-1-antitrypsin deficiency
·Rhodamine-positive cytoplasmic granules reflect copper accumulation in patients with Wilson disease
·A tumor in the cerebellum appearing as a cyst with a mural nodule and containing abundant Rosenthal fibers (corkscrew-shaped, intensely eosinophilic structures deriving from accumulation of alpha beta-crystallin within astrocytic processes) = Pilocytic astrocytoma
·Pick's bodies which are intracytoplasmic spherules composed of paired helical filaments, seen best with silver stains
·Lewy bodies (seen in Parkinson's disease)intracytoplasmic spherules that stain brightly eosinophilic
·Carotid body tumor is a paraganglioma, i.e., a tumor arising from one of the paraganglia & histologically are similar to pheochromocytomas secreting catecholamines
·Arnold-Chiari type 1 is more frequent than type 2 and consists of downward displacement of the cerebellar tonsils through the foramen magnum. Type 1 is frequently asymptomatic and an incidental autopsy finding
·Arnold-Chiari type 2 is associated with an abnormally small posterior fossa, with resultant downward displacement of cerebellar vermis and medulla through the foramen magnum. This leads to obstruction of CSF flow and hydrocephalus. Important associated abnormalities include lumbar myelomeningocele and syringomyelia.
·Post streptococcal glomerulonephritis, can follow either streptococcal pharyngitis (one to two weeks after the infection) or skin infection (three to six weeks after the infection)
·Immunohistochemistry for GFAP is used diagnostically to confirm an astrocytic origin of a neoplasm, but gives no information about mitotic or proliferative rate. Ki-67 is a nuclear factor (of uncertain function) whose expression correlates with neoplastic replicative activity.
·Breast cancer is unusual in that it produces both lytic and blastic metastases to bone. Breast and prostate cancers are the most common sources of bone metastases, but prostate metastases are usually blastic.
·There are three types of ovarian tumors that can produce large amounts of steroid hormones: 1.Sertoli-Leydig cell tumors originate from precursors of Sertoli and Leydig cells and usually produce male hormones, manifesting with masculinization or defeminization. 2.Fibroma-thecomas arise from stromal cells, are mostly composed of fibroblasts, and rarely manifest with endocrinologic signs. 3.Granulosa cell tumors develop from granulosa cells and may actively secrete estrogens. Precocious puberty appears if the patient is a preadolescent girl; adult women develop hyperplasia or carcinoma of the endometrium and fibrocystic change in the breast. Up to 20% to 25% of granulosa cell tumors are malignant.
·Teratomas behave as benign tumors if mature or as aggressive neoplasm if immature.
·About 60% of cerebellar abscess are related to middle ear infection.
·Myositis ossificans present in x-ray as flocculent radiodensities surrounding a radiolucent center
·Infection by HTLV-1 can lead to T-cell leukemia 20-30 years after the infection
·Toxic epidermal necrolysis (TEN) can appear clinically similar to staphylococcal scalded skin syndrome (SSSS), but it occurs in older patients, often in association with a new medication
·Churg-Strauss syndrome, also known as allergic granulomatosis and angiitis is a variant of polyarteritis nodosa and is clinically associated with asthma and eosinophilia
·In approximately 50% of patients with Steven Johnson Syndrome ( target lesions), no specific precipitating cause is identified. In the remainder of patients, however, a variety of causes have been implicated, including certain infections (herpes simplex, enteroviruses, Mycoplasma pneumoniae, Chlamydia, histoplasmosis), drugs (penicillin, sulfonamides, phenytoin, aspirin, corticosteroids, cimetidine, allopurinol, oral contraceptives), neoplasia (leukemia, lymphoma, multiple myeloma, internal malignancy), sarcoidosis, and foods (notably emulsifiers in margarine).
·2% of complete moles may transform into choriocarcinoma
·Infantile form of aortic coarctation is associated with patent ductus arteriosus (PDA). The stenotic segment is localized proximal to a PDA. Since blood pressure drops distal to the PDA, blood will shunt from the pulmonary artery to the aorta through the PDA. Thus, cyanosis develops in the lower part of the body only. Adult form of aortic coarctation in contrast, is not associated with PDA
·Increased plasma renin and plasma aldosterone are suggestive of a renin-secreting tumor, whereas primary hyperaldosteronism (Conn’s syndrome) would present as increased plasma aldosterone, but decreased plasma renin.
·Hashimoto's thyroiditis is an important cause of hypothyroidism, but this diagnosis would require a biopsy demonstrating infiltration with lymphocytes, macrophages and plasma cells, often associated with germinal center formation.
·Craniopharyngioma is more common in children and adolescents than in adults. Only 20% of craniopharyngiomas are diagnosed after age 40.
·The alveolar capillaries contain angiotensin-converting enzyme (ACE)
·Malnutrition associated with chronic alcoholism can lead to a severe magnesium deficiency. The effect of low serum magnesium on parathyroid hormone secretion (PTH) depends on severity and duration. An acute decrease in serum magnesium will increase PTH secretion, while a prolonged severe deficiency results in decreased PTH secretion.
·With prerenal failure the fractional sodium excretion is less than 1% in "typical" prerenal failure and < 2% in "typical" acute tubular necrosis.
·Renal papillary necrosis develops most commonly in diabetic patients (other conditions: analgesic abuse, urinary tract obstruction, and sickle cell disease are the most important) and may lead to acute renal failure. Fragments of tissue that slough off necrotic papillae may become impacted into the ureters and cause ureteral colic.
·The risk for cervical carcinoma include: young age at first coitus, human papilloma virus infection, multiple sexual partners, smoking, and multiparity. (Nulliparity is protective)
·Increased venous oxygen content is a pathognomonic sign of arteriovenous fistula.
·Gastrin is normally secreted from the gastric mucosa and is elevated postprandially, but in patients with Zollinger-Ellison syndrome, the extra-gastric location of the tumor does not allow food in the gastric lumen to have an effect on gastrin secretion. Thus, one should expect little to no change in circulating gastrin levels after eating in a patient with gastrinoma. In G-cell hyperplasia (which should be considered in the differential diagnosis of gastrinoma), serum gastrin levels typically increase after a test meal.
·Postgastrectomy patients should be instructed to eat more frequent, smaller meals that are high in fats to reduce the osmotic and/or carbohydrate load that is delivered to the small intestine.
·As many as 85% of patients with type 1 diabetes mellitus have islet cell autoantibodies directed against glutamic acid decarboxylase in their blood in the first few weeks after onset of the disease.
·A consequence of long-term hypertension is arteriolar dissolution and loss (rarefaction)
·Excessive GH decreases the sensitivity of peripheral tissues to insulin ("anti-insulin" effect). This tends to raise blood glucose and produce a compensatory hyperinsulinemia in acromegaly
·Plasma renin activity and thus aldosterone may be increased in Pheochromocytoma because of increased beta receptor activation on juxtaglomerular cells.
·Heaves are due to ventricular hypertrophy, and a left parasternal heave indicates right ventricular hypertrophy. Aortic stenosis produces left ventricular hypertrophy, and thus a sustained apical heave is felt.
·Fatty change of the macrovesicular type is entirely reversible if the noxious stimulus (eg. excessive alcohol intake) is removed
·Retinal angioma may be a "visible" manifestation of von Hippel-Lindau disease
oHyperplastic polyp: small, rounded rectal polyp demonstrating glands and sawtooth crypts composed of a proliferation of goblet and columnar epithelial cells. No atypia is seen ; comprise 90% of all colonic polyps and have no malignant potential
oPeutz-Jeghers polyps: also have no malignant potential, but tend to be larger and have a complex branching pattern
oTubular adenomas, tubulovillous adenomas, and villous adenomas : are all true neoplastic polyps containing dysplastic epithelium; the malignant potential of these polyps increases with size and the percentage of the polyp which has a villous configuration
·Volvulus usually develops in the poorly supported sigmoid colon.
·The chronic active hepatitis diagnosis is characterized by chronic inflammation with continuing necrosis of hepatocytes surrounding the portal tract (AKA limiting plate) and extending into the lobule with individual hepatocyte destruction (piecemeal necrosis)
Acute hepatitis histologically, shows lymphocytic infiltrates and ballooning degeneration of hepatocytes.
Chronic persistent hepatitis (minimal chronic hepatitis), is a disease state with minimal symptoms and mildly elevated enzymes. Inflammation is contained within the portal tracts and there is no lobular extension and no limiting plate activity or piecemeal necrosis
·Mixed testicular tumor: Microscopically, the tumor shows a variety of patterns, including lobules containing large cells with watery cytoplasm (Seminoma), structures resembling primitive glomeruli (Yolk sac tumor), syncytiotrophoblast (Choriocarcinoma), and shafts of undifferentiated cells with focal glandular differentiation (Embryonal carcinoma).
·Cold agglutinins are IgM and can be demonstrated by Coombs test at cold temperature (0-4 C). Cold agglutinins are usually triggered by Mycoplasma pneumoniae infection or lymphomas.
·Bowen's disease: opaque, gray-white, relatively flat penile plaque
Bowenoid papulosis: multiple, reddish-brown, papular lesions
Erythroplasia of Queyrat: soft, red plaque
·Mucinous cystadenoma can be benign, borderline, or malignant. Borderline or malignant tumor is ass. with a rare complication of pseudomyxoma peritonei (a condition in which large amounts of gelatinous, sticky, myxoid material fills the abdominal cavity and causes adhesion and obstruction of viscera).
·In the process of apoptosis, cells shrink and cytoplasmic organelles become more densely packed. Cytoplasmic blebs may form, and apoptotic bodies (membrane-bound cellular fragments) can be produced. The most characteristic feature of apoptosis is a distinctive peripheral aggregation of chromatin, sometimes accompanied by breaking up of the nucleus into several fragments. Inflammation is typically absent in apoptosis, in contrast to necrosis
·Statistically, the most common causes of maternal death in preeclampsia are cerebral hemorrhage and pulmonary complications, notably adult respiratory distress syndrome.
·Impetigo has a characteristic large golden crust; highly infectious
Erysipelas is characterized by large erythematous patches
·Features favoring the diagnosis of ductal carcinoma, rather than benign intraductal papilloma, include severe cytologic atypia, abnormal mitotic figures, and a cribriform growth pattern. Features that are specifically reassuring are the consistent presence of a fibrovascular core and both epithelial and myoepithelial cells in the papillary fronds.
·Adenocarcinoma is the peripheral lung tumor specifically ass. with lung scarring related to old granulomatous disease, old chronic obstructive lung disease, or other old damage to the lungs
·Demyelinating plaques in MS mature through an orderly sequence of events. Acute plaques show dense lymphohistiocytic infiltration and active digestion of myelin byproducts (myelin breakdown). These features tend to disappear as plaques age. As inflammatory infiltration and myelin breakdown abate, hyperplasia and hypertrophy of astrocytes transform the plaque into a gliotic area (gliosis), in which axons are relatively preserved but oligodendroglial cells are greatly diminished.
·Invasive ductal carcinoma is by far the most common variant of breast adenocarcinoma, accounting for approximately 75% to 80% of all invasive breast carcinomas. Invasive lobular carcinoma is the second most frequent histologic type
·Acute mastitis, frequently complicated by breast abscess formation, typically develops in the postpartum period, when the nipples are first subjected to the physical stresses of breast feeding.
·Most patients with empty sella syndrome have sufficient residual pituitary parenchyma to prevent hypopituitarism.
·Myxopapillary ependymoma, a variant of ependymoma, almost always occurs in the distal segment of the spinal cord, ie, the conus medullaris.
·Valvular damage in rheumatic fever result in thickened, blunted cardiac valve leaflets, often with fibrous bridging between valve leaflets and calcification, frequently take on a "fish mouth" or "button hole" stenotic morphology.
Mitral valve prolapse: Ballooning of valve leaflets
Calcification of the mitral annulus, seen in elderly individuals
Acute bacterial endocarditis: large vegetations and leaflet perforation; usually involves healthy, rather than previously damaged, valves
Marantic (nonbacterial thrombotic)endocarditis: tiny vegetations along line of closure
·Features typical of mucopolysaccharidoses include hepatomegaly, skeletal abnormalities, and, often, mental retardation. The two exceptions to the mental retardation are the milder conditions, Morquio syndrome and Scheie syndrome
·McCune-Albright syndrome is the combination of precocious sexual development, irregularly shaped ("coast of Maine") pigmented skin macules, and polyostotic fibrous dysplasia (characterized by local bony defects containing unmineralized whorls of connective tissue)
·"Small blue cell tumors": a heterogeneous group of malignant neoplasms including Ewing sarcoma, small cell carcinoma of the lung, lymphoma, and neuroblastoma.
·Pheochromocytomas, and their related counterparts in extra-adrenal sites called paragangliomas, are notorious because the only reliable indicator of metastatic potential is the presence of distant metastases. Their malignancy cannot be determined by microscopic examination
·Unlike tropical sprue (which may be related to enterotoxigenic E. coli infection), which involves the entire small bowel, celiac sprue is usually limited to the proximal small bowel.
·Herpes simplex encephalitis characteristically involves the lower portions of the cerebral cortex, notably the temporal lobes and the base of the frontal lobes, possibly because the infection spreads from the oropharynx
·Patients with celiac disease have an increased risk of developing gastrointestinal lymphoma
·Accumulation of iron due to iron overloading (e.g., dietary excess, or multiple transfusions) is termed hemosiderosis. An inherited abnormality of iron handling causing the same accumulation of iron is called hemochromatosis; the gene is tightly linked to the HLA-A3 locus
·Elevated AST and ALT with a AST/ALT ratio of greater than 1.5 is strongly suggestive of alcoholic hepatitis. In viral hepatitis, both AST and ALT are elevated, but the ratio is usually less than 1.5
·Gaucher's disease: deficient beta-glucocerebrosidase
·Krabbe's disease : deficient beta-galactocerebrosidase
·Pancreatic pseudocyst is not a true cyst; it is lined by granulation tissue and collagen. It contains pancreatic juices and lysed blood, so rupture would spill the active digestive enzymes onto the adjacent viscera, particularly the stomach, small intestine, and transverse colon. Digestive action produces potentially severe gastrointestinal hemorrhage.
·RS cell is a giant, usually binucleated cell, with large "inclusion-like" nucleoli. The nuclei are similar to each other, giving the impression of mirror images.
Classic RS cells and lacunar cells are probably transformed B lymphocytes and are positive for CD15 and CD30.
Lacunar cells are mononucleated and surrounded by a pericellular halo, seen in Nodular sclerosing HD
The lymphohistiocytic (L+H) cell is a variant of RS cell with a characteristic convoluted nucleus resembling a popcorn kernel ("popcorn cell"); seen in Lymphocyte predominance HD
·The hallmark of osteomalacia is widened osteoid seams. Although the trabeculae are normal in number and size, they do not mineralize effectively, and the rim of uncalcified osteoid is much larger than normal. There are increased numbers of osteoblasts which lay down increased quantities of osteoid in an effort to strengthen the bone. Unfortunately, the increased osteoid is not mineralized and the bone remains soft and weak.
·Near complete absence of muscle tone and peristalsis is characteristic of involvement of the esophagus with scleroderma, which causes replacement of muscle by dense connective tissue. Similar changes in the dermis cause the skin to be thickened. The thickened, shiny skin of the hands may cause them to resemble claws.
·Primary sclerosing cholangitis, a disorder with a probable autoimmune component that is associated with ulcerative colitis is characterized by inflammation and fibrosis of the intrahepatic and extrahepatic bile ducts, producing alternating strictures and dilatation of the structures. These changes are seen as "beading" on ERCP.
·A facial or scalp port-wine nevus (a facial angioma, or nevus flammeus) should specifically suggest evaluation for Sturge-Weber disease. The "port-wine stain," may overlie meningeal angiomatosis on the surface of the ipsilateral hemisphere
·While most cases of Diverticulitis involve the left colon, the right colon is also sometimes involved, and may clinically mimic appendicitis.
·Taussig-Bing malformation: aorta arises from a morphologic right ventricle located on the right side of the heart. The pulmonary artery overrides a ventricular septal defect
"common pattern" of transposition: the aorta arises from a morphologic right ventricle on the right side of the heart, and the pulmonary artery arises from a morphologic left ventricle on the left side of the heart
"corrected pattern" of transposition: the aorta arises from a morphologic right ventricle on the left side of the heart, and the pulmonary artery arises from a morphologic left ventricle on the right side of the heart
·The total peripheral resistance increases when a kidney is removed. The cardiac output decreases and so does the pulmonary flow. and total renal blood flow.
·Repeated episodes of stable angina pectoris typically cause gradual loss of myocytes, which is seen pathologically as small patches of fibrosis and vacuolization of damaged myocytes, typically in subendocardial locations (which are relatively poorly perfused)
·Verapamil is a "first-generation" calcium channel blocker that has been associated with an accelerated progression of CHF in certain patients
Amlodipine and felodipine are the most commonly used calcium channel blocking agents in patients with CHF. These two medications may actually produce a small increase in myocardial contractility and cardiac output
·In severe anemia, diminished transport of oxygen in the blood leads to hypoxia in the tissues. The hypoxia causes small arteries and arterioles to dilate, which allows greater-than-normal amounts of blood to return to the heart. This decrease in viscosity lowers the resistance to blood flow in the peripheral tissues (i.e., decreases peripheral vascular resistance) allowing even greater amounts of blood to return to the heart. Thus cardiac output increases.
·Behcet's syndrome is a multisystem disorder presenting with uveitis, as well as recurrent aphthous ulcers on the genitalia or in the mouth
·Some patients are resistant to HIV infection because they carry two defective copies of the gene encoding the CCR5 coreceptor. CCR5 is a receptor for β-chemokines and serves as a coreceptor for HIV internalization.


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