General and Systemic Pathology: Organ Systems Review

Comprehensive practice flashcards reviewing core topics in hepatobiliary, genital, musculoskeletal, and renal pathology based on lecture slides.

Hepatic Acinus (Rappaport)

The functional unit of the liver parenchyma, divided into three metabolic regions: Zone 1 (periportal, receiving highest concentrations of oxygen and nutrients), Zone 2 (intermediate), and Zone 3 (centrilobular, closest to the central vein with lowest oxygenation).

Hepatic Steatosis

A reversible metabolic alteration characterized by abnormal accumulation of triglycerides within hepatocyte cytoplasm without initial structural destruction, predominantly localized to Zone 3 (centrilobular) and microscopically displaying intracellular clear fat vacuoles displacing nuclei peripherally.

Cholestasis

An impairment or cessation of bile flow resulting in intracellular retention of bile within hepatocytes and canaliculi, manifesting microscopically as yellow-brown bile plugs, intracellular pigment accumulation, and hepatocyte ballooning degeneration.

Cirrosis Hepatica (Hepatic Cirrhosis)

A chronic, irreversible liver disease characterized by diffuse fibrosis, formation of thick fibrous septa that bridge portal triads and central veins, regenerative parenchymal nodules, and total disruption of normal hepatic architecture.

Focal Nodular Hyperplasia

A benign, non-neoplastic hyperplastic liver mass arising as an arterial vascular response; defined by well-circumscribed normal hepatocyte proliferation organized around a central stellate fibrous scar radiating fibrous septa.

Hepatocellular Carcinoma

A primary malignant tumor derived from hepatocytes, most commonly developing against a background of chronic hepatitis (HBV, HCV) and cirrhosis; microscopically forming thickened cords and trabeculae of atypical hepatocytes with marked nuclear hyperchromasia.

Colangiocarcinoma (Cholangiocarcinoma)

A primary malignant hepatic neoplasm arising from intrahepatic or extrahepatic bile duct epithelium, characterized by invasive irregular malignant glands embedded within an abundant, dense desmoplastic fibrous stroma and frequent mucin production.

Enzymatic Fat Necrosis

A specific pattern of tissue necrosis typical of acute pancreatitis, caused by activated pancreatic lipase digesting peripancreatic adipose tissue to release free fatty acids that complex with calcium to form basophilic chalky-white deposits (saponification).

Pancreatic Ductal Adenocarcinoma

An aggressive malignant epithelial neoplasm most commonly situated in the head of the pancreas; characterized histopathologically by invasive atypical glandular structures, intense desmoplastic stroma, and a high frequency of perineural invasion.

Cervical Transformation Zone

The dynamic junctional region of the uterine cervix where glandular endocervical columnar epithelium undergoes physiological squamous metaplasia into stratified squamous epithelium, representing the predilection site for HPV infection and neoplastic transformation.

Superficial Squamous Cells

Large, flat, polygonal mature squamous epithelial cells observed on cervical cytology, featuring abundant cytoplasm and a small, condensed pyknotic nucleus, reflecting predominant estrogen stimulation.

Clue Cells

Vaginal squamous epithelial cells whose borders are obscured and stippled by dense adherent coccobacilli (predominantly Gardnerella vaginalis), pathognomonic for bacterial vaginosis in vaginal smears.

Trichomonas vaginalis (Cytology)

A flagellated protozoan parasite identified on gynecologic smears as oval or pyriform organisms with pale, cyanophilic cytoplasm and an eccentric nucleus, typically seen within a marked purulent inflammatory background.

Candida (Cytology)

A mycotic infection of the lower female genital tract characterized cytologically by branching pseudohyphae (filaments) accompanied by round or oval budding yeast forms (blastospores) amid squamous cells and acute inflammatory debris.

Actinomyces (Cervical Smear)

Filamentous, radiating bacterial colonies resembling dense cotton-ball clusters or tangled spidery balls on cervical Pap smears, classically associated with prolonged use of an intrauterine device (IUD).

Herpes Simplex Virus (HSV) Cytopathic Effect

Viral cellular alterations in squamous epithelium characterized microscopically by multinucleation, nuclear molding, peripheral margination of chromatin, and eosinophilic intranuclear viral inclusions.

Vaginal Atrophy

Epithelial thinning secondary to systemic estrogen deficiency, cytologically defined by a marked predominance of immature parabasal squamous cells displaying enlarged nuclei, scant cytoplasm, and an absence of mature superficial cells.

ASC-US (Atypical Squamous Cells of Undetermined Significance)

A Bethesda diagnostic category designating squamous cells with subtle nuclear enlargement and slight hyperchromasia that exceed reactive changes but fall short of definitive low-grade intraepithelial lesions.

Low-Grade Squamous Intraepithelial Lesion (LSIL / LIEBG)

A cervical pre-neoplastic lesion corresponding to CIN I; characterized by active productive HPV replication, cellular koilocytosis, mild nuclear atypia, and dysplastic changes strictly confined to the lower third of the cervical epithelium.

High-Grade Squamous Intraepithelial Lesion (HSIL / LIEAG)

A severe precancerous squamous alteration corresponding to CIN II and CIN III; characterized histologically by loss of epithelial maturation, marked nuclear pleomorphism, elevated nuclear-to-cytoplasmic ratio, and abnormal mitoses involving more than two-thirds or the full thickness of the epithelium.

Condiloma Acuminado (Condyloma Acuminatum)

A benign exophytic, papillary anogenital verrucous lesion induced predominantly by low-risk HPV types $6$ and $11$; microscopically displaying hyperkeratosis, acanthosis, papillomatosis, and prominent superficial koilocytosis.

Sarcoma Botryoides

A variant of embryonal rhabdomyosarcoma arising beneath mucosal membranes of the vagina, cervix, or bladder in infants and children younger than $10$ years; macroscopically displaying a soft, gelatinous grape-like polypoid mass positive for desmin and myogenin.

Uterine Leiomyosarcoma

A highly aggressive malignant mesenchymal neoplasm originating from myometrial smooth muscle; microscopically demonstrating intersecting fascicles of atypical spindle cells, marked nuclear pleomorphism, geographic coagulative tumor necrosis, and brisk mitotic activity.

Tubal Ectopic Pregnancy

The extrauterine implantation of a fertilized blastocyst within the fallopian tube (most commonly the ampulla); histologically characterized by chorionic villi, extravillous trophoblast, hemorrhage, and decidual changes invading the tubal muscular wall.

Seminoma

The most common testicular germ cell tumor in young men ($30\text{--}40$ years); characterized grossly as a fleshy, homogenous lobulated grey-white mass and microscopically by uniform large cells with clear glycogenated cytoplasm, prominent nucleoli, and fibrous septa containing lymphocytes.

Embryonal Carcinoma

A highly aggressive testicular nonseminomatous germ cell tumor occurring predominantly in men aged $20\text{--}30$ years; displaying a heterogeneous, poorly demarcated mass with extensive hemorrhage and necrosis, comprised of primitive pleomorphic anaplastic cells forming tubular, alveolar, or solid sheets.

Benign Prostatic Hyperplasia (BPH)

A non-malignant nodular proliferation of glandular and fibromuscular stromal elements originating within the prostatic transition (periurethral) zone under the influence of dihydrotestosterone (DHT) produced via $5\text{--}\text{alpha-reductase}$, causing urinary outflow obstruction.

Corpora Amylacea

Concentric, laminated proteinaceous and calcified concretions found within the lumens of benign prostatic glands, typically increased in number within hyperplastic prostatic tissue.

Gleason Score

A histopathologic architectural grading system used to stratify the aggressiveness of prostate adenocarcinoma by adding the primary (predominant) architectural pattern grade ($1\text{--}5$) to the secondary pattern grade ($1\text{--}5$).

Osteoma Osteoide (Osteoid Osteoma)

A benign osteoblastic bone tumor classically causing nocturnal pain relieved by NSAIDs; defined by a vascular osteoid-forming central radiolucent nidus measuring $< 2\text{ cm}$ surrounded by a thick zone of dense, reactive cortical bone sclerosis.

Osteoblastoma

A benign bone-forming lesion histologically identical to osteoid osteoma but distinguished by a nidus size of $> 2\text{ cm}$, an absence of marked surrounding sclerosis, and a predilection for the vertebral column.

Osteosarcoma

The most common primary malignant bone neoplasm in adolescents, classically arising within the metaphyseal region of long bones around the knee; pathognomonically characterized by malignant mesenchymal cells directly synthesizing unmineralized bone matrix (osteoid).

Codman Triangle

A radiologic sign produced when an aggressive cortical-destructive bone lesion rapidly elevates the periosteum away from the cortex, causing the periosteum to form a triangular wedge of reactive bone at its peripheral angle.

Osteochondroma

The most common benign bone tumor; an exophytic, cartilage-capped bony outgrowth (exostosis) arising from the external metaphyseal cortex of long bones whose medullary and cortical cavities maintain direct continuity with the underlying native bone.

Enchondroma

A benign intramedullary neoplasm composed of mature hyaline cartilage lobules developing within the marrow cavity of small tubular bones of the hands and feet, often displaying characteristic 'rings and arcs' calcifications.

Condrosarcoma (Chondrosarcoma)

A malignant bone neoplasm characterized by the production of chondroid matrix without osteoid formation, arising primarily in the axial skeleton (pelvis, shoulder) of adults aged $40\text{--}70$ years, and displaying chondrocytic atypia with frequent binucleation.

Sarcoma de Ewing (Ewing Sarcoma)

A malignant primitive bone tumor of children and adolescents ($10\text{--}20$ years) localized to the diaphysis; microscopically composed of uniform sheets of small round blue cells with glycogen-rich cytoplasm, linked to the $t(11;22)(q24;q12)$ EWSR1-FLI1 fusion.

Giant Cell Tumor of Bone (Osteoclastoma)

A locally aggressive osteolytic lesion classically arising in the epiphysis of long bones in adults aged $20\text{--}40$ years; composed of numerous multinucleated osteoclast-like giant cells distributed uniformly among mononuclear neoplastic stromal cells expressing RANKL.

Hydronephrosis

Aseptic dilation of the renal pelvis and calyces secondary to urinary tract obstruction, leading to progressive parenchymal compression, tubular atrophy, and thinning of the renal cortex.

Chronic Glomerulonephritis

The end-stage irreversible destruction of renal architecture resulting from chronic glomerular disease; macroscopically presenting as bilaterally shrunken, symmetrically contracted kidneys with finely granular surfaces and diffuse global glomerulosclerosis.

Clear Cell Renal Cell Carcinoma

The most common primary renal malignancy, derived from proximal convoluted tubular epithelium and strongly linked to VHL gene loss; characterized histologically by nests and solid sheets of cells containing abundant lipid- and glycogen-cleared cytoplasm surrounded by delicate sinusoidal blood vessels.

Papillary Renal Cell Carcinoma

The second most frequent malignant epithelial tumor of the kidney, associated with MET proto-oncogene alterations; characterized histologically by true papillary fibrovascular cores lined by atypical cuboidal or columnar epithelial cells accompanied by aggregates of foamy macrophages.