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ASCP PA practice questions

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Question 1Surgical Pathology and Autopsy Pathology

Which gross feature most reliably distinguishes an adenoma from an adenocarcinoma of the colon?

  1. Size greater than 2 cm
  2. Invasion into the submucosa Correct answer.
  3. Villous architecture
  4. Presence of a stalk

Explanation

The defining criterion for malignancy in a colorectal epithelial neoplasm is invasion through the muscularis mucosae into the submucosa. Size, stalk configuration, and villous architecture are risk features but do not themselves establish carcinoma.

Question 2Surgical Pathology and Autopsy Pathology

A breast biopsy shows a proliferation of uniform cells filling and distending ducts with sharply demarcated borders and central necrosis. What is the most appropriate diagnosis?

  1. Atypical ductal hyperplasia
  2. Ductal carcinoma in situ, comedo type Correct answer.
  3. Sclerosing adenosis
  4. Invasive ductal carcinoma

Explanation

Uniform monomorphic cells filling ducts, with central comedo necrosis and sharp borders, define ductal carcinoma in situ. Absence of stromal invasion distinguishes it from invasive carcinoma.

Question 3Surgical Pathology and Autopsy Pathology

Which histologic finding is characteristic of a fibroadenoma?

  1. Cellular stroma with leaf-like architecture
  2. Infiltrative borders with desmoplastic stroma
  3. Biphasic proliferation of stroma and ducts Correct answer.
  4. Adipose tissue with fibrous bands

Explanation

Fibroadenomas are biphasic lesions with proliferation of both stroma and glandular elements, typically well circumscribed. Leaf-like architecture suggests phyllodes tumor, and infiltrative borders suggest malignancy.

Question 4Surgical Pathology and Autopsy Pathology

A lung biopsy shows sheets of small blue cells with nuclear molding, crush artifact, and scant cytoplasm. What is the most likely diagnosis?

  1. Small cell carcinoma Correct answer.
  2. Carcinoid tumor
  3. Squamous cell carcinoma
  4. Adenocarcinoma

Explanation

Small cell carcinoma is defined by small cells with scant cytoplasm, nuclear molding, and crush artifact. Squamous and adenocarcinoma show differentiation such as keratinization or gland formation, and carcinoid shows uniform neuroendocrine nests.

Question 5Surgical Pathology and Autopsy Pathology

A thyroid lesion shows papillary architecture with optically clear nuclei and nuclear grooves. What is the diagnosis?

  1. Papillary thyroid carcinoma Correct answer.
  2. Medullary thyroid carcinoma
  3. Follicular adenoma
  4. Hashimoto thyroiditis

Explanation

Papillary carcinoma is diagnosed by nuclear features including clearing (Orphan Annie eyes), grooves, and pseudoinclusions, often with papillary architecture. Follicular adenoma lacks these nuclear changes.

Question 6Surgical Pathology and Autopsy Pathology

Which feature best distinguishes a benign nevus from melanoma on histology?

  1. Maturation with depth and absence of atypical mitoses Correct answer.
  2. Nests of melanocytes at the dermoepidermal junction
  3. Presence of melanin pigment
  4. Lymphocytic infiltrate at the base

Explanation

Benign nevi show maturation of nests with depth and lack atypical mitoses, whereas melanoma shows poor maturation and atypical mitoses. Pigment and junctional nests occur in both.

Question 7Surgical Pathology and Autopsy Pathology

In an autopsy, which finding is most consistent with early myocardial infarction of approximately 12 hours' duration?

  1. Dense collagenous scar
  2. Coagulative necrosis with neutrophilic infiltrate Correct answer.
  3. Granulation tissue with capillaries
  4. Contraction band necrosis

Explanation

By about 12–24 hours, myocardial infarction shows coagulative necrosis with neutrophilic infiltration. Granulation tissue appears at 1–2 weeks, and a dense scar develops after weeks to months.

Question 8Surgical Pathology and Autopsy Pathology

Which organism is most commonly associated with pseudomembranous colitis after antibiotic use?

  1. Escherichia coli
  2. Campylobacter jejuni
  3. Entamoeba histolytica
  4. Clostridioides difficile Correct answer.

Explanation

Pseudomembranous colitis after antibiotics is caused by toxin-producing Clostridioides difficile. Other organisms cause different patterns such as invasive dysentery or amebic ulcers.

Question 9Surgical Pathology and Autopsy Pathology

A gastric biopsy shows intestinal-type epithelium with goblet cells replacing gastric mucosa. This finding is termed:

  1. Dysplasia
  2. Atrophy
  3. Hyperplasia
  4. Intestinal metaplasia Correct answer.

Explanation

Intestinal metaplasia is replacement of gastric epithelium by goblet cell–containing intestinal-type epithelium, often in chronic gastritis. Dysplasia implies cytologic atypia, and atrophy refers to gland loss.

Question 10Surgical Pathology and Autopsy Pathology

Which feature most supports a diagnosis of a benign follicular adenoma over a follicular carcinoma of the thyroid?

  1. Nuclear pleomorphism
  2. Presence of colloid
  3. Follicular architecture
  4. Intact capsule without capsular or vascular invasion Correct answer.

Explanation

Follicular carcinoma is diagnosed by capsular or vascular invasion; an intact capsule without invasion supports adenoma. Colloid and follicular architecture occur in both.

Question 11Surgical Pathology and Autopsy Pathology

A liver biopsy shows bridging fibrosis with regenerative nodules. What is the most appropriate diagnosis?

  1. Hemochromatosis
  2. Acute hepatitis
  3. Cirrhosis Correct answer.
  4. Steatosis

Explanation

Cirrhosis is defined by bridging fibrosis with regenerative nodules. Steatosis is fat accumulation, and acute hepatitis shows inflammation without nodular fibrosis.

Question 12Surgical Pathology and Autopsy Pathology

Which histologic pattern is characteristic of membranous nephropathy?

  1. Segmental sclerosis of glomeruli
  2. Crescents in Bowman space
  3. Subepithelial immune deposits with thickened basement membrane Correct answer.
  4. Mesangial proliferation with IgA deposits

Explanation

Membranous nephropathy shows subepithelial immune complex deposits and basement membrane thickening. IgA deposits indicate IgA nephropathy, crescents indicate crescentic GN, and segmental sclerosis indicates FSGS.

Question 13Surgical Pathology and Autopsy Pathology

A renal tumor shows nests of clear cells with a delicate vascular network. What is the most likely diagnosis?

  1. Chromophobe renal cell carcinoma
  2. Urothelial carcinoma
  3. Papillary renal cell carcinoma
  4. Clear cell renal cell carcinoma Correct answer.

Explanation

Clear cell renal cell carcinoma shows nests of cells with clear cytoplasm and a delicate branching vasculature. Papillary and chromophobe carcinomas have different architectures and cell types.

Question 14Surgical Pathology and Autopsy Pathology

Which feature is characteristic of a serous borderline ovarian tumor?

  1. Stromal invasion by tumor cells
  2. Solid sheets of anaplastic cells
  3. Mucin-filled cysts with goblet cells
  4. Hierarchical branching papillae with epithelial stratification Correct answer.

Explanation

Serous borderline tumors show hierarchical branching papillae with epithelial stratification and mild atypia but no stromal invasion. Invasion indicates carcinoma, and mucin-filled cysts suggest mucinous tumors.

Question 15Surgical Pathology and Autopsy Pathology

A prostate needle biopsy shows small glands infiltrating between benign glands with prominent nucleoli. What is the most likely diagnosis?

  1. Acute prostatitis
  2. Benign prostatic hyperplasia
  3. Prostatic adenocarcinoma Correct answer.
  4. Atrophy

Explanation

Infiltrative small glands with prominent nucleoli indicate prostatic adenocarcinoma. BPH shows nodular proliferation of glands and stroma without infiltration.

Question 16Surgical Pathology and Autopsy Pathology

Which histologic finding is most specific for acute appendicitis?

  1. Fecalith in the lumen
  2. Serosal congestion
  3. Neutrophilic infiltration of the muscularis propria Correct answer.
  4. Lymphoid hyperplasia

Explanation

Acute appendicitis is defined by neutrophilic infiltration extending into the muscularis propria. Lymphoid hyperplasia and fecaliths may occur without true transmural inflammation.

Question 17Surgical Pathology and Autopsy Pathology

Which feature distinguishes ulcerative colitis from Crohn disease on biopsy?

  1. Fistula formation
  2. Continuous mucosal involvement Correct answer.
  3. Granulomas
  4. Transmural inflammation

Explanation

Ulcerative colitis typically shows continuous mucosal inflammation limited to the colon, whereas Crohn disease is patchy and transmural with granulomas and fistulas.

Question 18Surgical Pathology and Autopsy Pathology

A lymph node biopsy shows Reed-Sternberg cells in an inflammatory background. What is the diagnosis?

  1. Diffuse large B-cell lymphoma
  2. Follicular lymphoma
  3. Hodgkin lymphoma Correct answer.
  4. Chronic lymphocytic leukemia

Explanation

Reed-Sternberg cells with an appropriate inflammatory background define classic Hodgkin lymphoma. Other lymphomas lack these cells.

Question 19Surgical Pathology and Autopsy Pathology

Which feature best identifies a high-grade squamous intraepithelial lesion (HSIL) on cervical biopsy?

  1. Glandular mucinous epithelium
  2. Full-thickness loss of maturation with nuclear atypia Correct answer.
  3. Chronic inflammation of the stroma
  4. Koilocytic atypia confined to the lower third

Explanation

HSIL shows loss of maturation with nuclear atypia extending into the upper epithelial layers. Koilocytic atypia limited to the lower third indicates LSIL.

Question 20Surgical Pathology and Autopsy Pathology

A bone marrow biopsy shows sheets of plasma cells with a monoclonal protein on serum electrophoresis. What is the diagnosis?

  1. Hodgkin lymphoma
  2. Chronic lymphocytic leukemia
  3. Myelofibrosis
  4. Multiple myeloma Correct answer.

Explanation

Sheets of clonal plasma cells with a monoclonal protein indicate multiple myeloma. CLL shows small lymphocytes, and myelofibrosis shows fibrosis with atypical megakaryocytes.

Question 21Surgical Pathology and Autopsy Pathology

Which gross finding at autopsy is most characteristic of a ruptured berry aneurysm?

  1. Intracerebral hemorrhage in the basal ganglia
  2. Subdural hematoma over the hemisphere
  3. Epidural hematoma over the convexity
  4. Subarachnoid hemorrhage at the base of the brain Correct answer.

Explanation

Berry aneurysms typically rupture into the subarachnoid space, producing hemorrhage at the base of the brain. Epidural and subdural hematomas arise from trauma to meningeal vessels.

Question 22Surgical Pathology and Autopsy Pathology

Which histologic feature is typical of a glioblastoma?

  1. Rosenthal fibers and Rosenthal fibers only
  2. Pseudopalisading necrosis and microvascular proliferation Correct answer.
  3. Uniform cells with myxoid background
  4. Biphasic pattern with reticulin

Explanation

Glioblastoma shows pseudopalisading necrosis and microvascular proliferation, which define its high-grade nature. Rosenthal fibers suggest pilocytic astrocytoma.

Question 23Surgical Pathology and Autopsy Pathology

A skin biopsy shows a well-circumscribed dermal nodule of basaloid cells with peripheral palisading and clefting. What is the diagnosis?

  1. Dermatofibroma
  2. Squamous cell carcinoma
  3. Melanoma
  4. Basal cell carcinoma Correct answer.

Explanation

Basal cell carcinoma shows basaloid cell nests with peripheral palisading and clefting from the surrounding stroma. Squamous cell carcinoma shows keratinization, and melanoma shows atypical melanocytes.

Question 24Surgical Pathology and Autopsy Pathology

Which feature most favors a diagnosis of a benign thyroid nodule over a follicular carcinoma on frozen section?

  1. Absence of capsular invasion Correct answer.
  2. Nuclear atypia
  3. Presence of colloid
  4. Follicular architecture

Explanation

Capsular invasion is a key criterion for follicular carcinoma; its absence favors a benign adenoma. Colloid and follicular architecture occur in both.

Question 25Surgical Pathology and Autopsy Pathology

Which finding is characteristic of a colonic tubular adenoma with low-grade dysplasia?

  1. Invasion into the submucosa
  2. Signet ring cells
  3. Necrosis with pseudopalisading
  4. Crowded elongated glands with hyperchromatic nuclei Correct answer.

Explanation

Tubular adenomas with low-grade dysplasia show crowded, elongated glands with hyperchromatic nuclei but no invasion. Invasion indicates carcinoma, and signet ring cells indicate mucinous carcinoma.

Question 26Surgical Pathology and Autopsy Pathology

A 45-year-old woman undergoes excisional biopsy of a pigmented skin lesion. Histology shows a dermal proliferation of uniform melanocytes arranged in nests and cords, with no pagetoid spread or significant atypia. Which diagnosis is most likely?

  1. Intradermal nevus Correct answer.
  2. Superficial spreading melanoma
  3. Blue nevus
  4. Spitz nevus

Explanation

An intradermal nevus is characterized by nests and cords of bland melanocytes confined to the dermis, often with maturation and no pagetoid spread. Melanoma would show atypical melanocytes with pagetoid scatter and mitoses. Blue nevus shows spindled melanocytes in the dermis without nesting. Spitz nevus typically shows epithelioid and spindled cells with Kamino bodies, usually in a younger patient.

Question 27Surgical Pathology and Autopsy Pathology

At autopsy, a 60-year-old man with a history of hypertension is found to have a large intracerebral hemorrhage centered in the basal ganglia. Which underlying process is most likely responsible?

  1. Hypertensive small vessel disease Correct answer.
  2. Cerebral amyloid angiopathy
  3. Ruptured saccular aneurysm
  4. Arteriovenous malformation

Explanation

Hypertensive small vessel disease typically causes hemorrhage in the basal ganglia, thalamus, pons, and cerebellum due to rupture of small penetrating arteries. Cerebral amyloid angiopathy tends to cause lobar hemorrhages in elderly patients. Saccular aneurysms cause subarachnoid hemorrhage. Arteriovenous malformations can cause hemorrhage but are less common and often lobar.

Question 28Surgical Pathology and Autopsy Pathology

A 30-year-old woman presents with a breast mass. Core biopsy shows a well-circumscribed proliferation of uniform, bland stromal cells with compressed ducts forming a slit-like pattern. Which diagnosis is most likely?

  1. Phyllodes tumor
  2. Fibrocystic change
  3. Fibroadenoma Correct answer.
  4. Tubular carcinoma

Explanation

Fibroadenoma is a benign fibroepithelial lesion with proliferation of both stroma and epithelium, typically well-circumscribed and with compressed ducts. Phyllodes tumor also is fibroepithelial but shows a leaf-like architecture and increased stromal cellularity. Tubular carcinoma is a well-differentiated invasive carcinoma with angulated tubules. Fibrocystic change shows cysts and fibrosis without a circumscribed mass.

Question 29Surgical Pathology and Autopsy Pathology

A 55-year-old man with a history of alcohol abuse has a liver biopsy showing steatosis, ballooned hepatocytes, and Mallory-Denk bodies. Which diagnosis is most likely?

  1. Chronic hepatitis C
  2. Alcoholic steatohepatitis Correct answer.
  3. Primary biliary cholangitis
  4. Hemochromatosis

Explanation

Alcoholic steatohepatitis is characterized by steatosis, ballooning degeneration, Mallory-Denk bodies, and neutrophilic infiltrate, often with pericellular fibrosis. Chronic hepatitis C shows portal inflammation and interface hepatitis. Primary biliary cholangitis shows florid duct lesions and granulomas. Hemochromatosis shows iron deposition in hepatocytes.

Question 30Surgical Pathology and Autopsy Pathology

A 65-year-old man has a lung biopsy showing sheets of small blue cells with scant cytoplasm, nuclear molding, and frequent mitoses. Which immunohistochemical marker is most likely to be positive?

  1. TTF-1
  2. Cytokeratin 5/6
  3. CD56 Correct answer.
  4. p40

Explanation

Small cell lung carcinoma is a neuroendocrine tumor that typically expresses neuroendocrine markers such as CD56, synaptophysin, and chromogranin. Cytokeratin 5/6 and p40 are markers of squamous differentiation. TTF-1 can be positive in small cell carcinoma but is less specific than CD56 for neuroendocrine differentiation.

Question 31Surgical Pathology and Autopsy Pathology

A 70-year-old man undergoes prostatectomy for adenocarcinoma. The pathology report describes tumor invading through the prostatic capsule into periprostatic soft tissue. What is the pT category?

  1. pT3a Correct answer.
  2. pT4
  3. pT2c
  4. pT3b

Explanation

In the AJCC staging for prostate cancer, pT3a indicates extracapsular extension (tumor extending through the capsule into periprostatic tissue). pT2c indicates tumor involving both lobes but confined to the prostate. pT3b indicates seminal vesicle invasion. pT4 indicates invasion of adjacent structures such as the rectum or bladder neck.

Question 32Surgical Pathology and Autopsy Pathology

A 50-year-old woman has a thyroidectomy for a nodule. Histology shows a well-circumscribed encapsulated tumor composed of follicles with minimal nuclear atypia and no capsular or vascular invasion. Which diagnosis is most likely?

  1. Follicular adenoma Correct answer.
  2. Papillary thyroid carcinoma
  3. Medullary thyroid carcinoma
  4. Follicular carcinoma

Explanation

Follicular adenoma is a benign encapsulated follicular neoplasm lacking capsular and vascular invasion. Follicular carcinoma would show capsular or vascular invasion. Papillary carcinoma shows characteristic nuclear features (Orphan Annie eyes, grooves, pseudoinclusions). Medullary carcinoma shows nests of cells with amyloid stroma and calcitonin positivity.

Question 33Surgical Pathology and Autopsy Pathology

A 60-year-old man with chronic kidney disease has a renal biopsy showing globally sclerosed glomeruli and severe interstitial fibrosis and tubular atrophy. Which term best describes these changes?

  1. Rapidly progressive glomerulonephritis
  2. Acute tubular necrosis
  3. Minimal change disease
  4. End-stage kidney disease Correct answer.

Explanation

End-stage kidney disease is characterized by extensive glomerulosclerosis, interstitial fibrosis, and tubular atrophy, reflecting irreversible chronic injury. Acute tubular necrosis shows tubular cell injury without prominent sclerosis. Rapidly progressive glomerulonephritis shows crescents. Minimal change disease shows normal glomeruli by light microscopy.

Question 34Surgical Pathology and Autopsy Pathology

A 40-year-old woman has a cystic ovarian mass. Histology shows a cystic lining of ciliated columnar cells with mild atypia and no stromal invasion. Which diagnosis is most likely?

  1. Clear cell carcinoma
  2. Mucinous cystadenoma
  3. Serous cystadenoma Correct answer.
  4. Endometrioid carcinoma

Explanation

Serous cystadenoma is a benign cystic neoplasm lined by ciliated columnar epithelium, often with mild atypia but no invasion. Mucinous cystadenoma is lined by mucinous epithelium. Endometrioid carcinoma shows glandular architecture resembling endometrium and is malignant. Clear cell carcinoma shows clear cells and hobnail cells.

Question 35Surgical Pathology and Autopsy Pathology

A 55-year-old man has a colonoscopy that reveals a 2-cm pedunculated polyp in the sigmoid colon. Histology shows tubular architecture with low-grade dysplasia confined to the mucosa. Which diagnosis is most likely?

  1. Sessile serrated lesion
  2. Hyperplastic polyp
  3. Villous adenoma
  4. Tubular adenoma Correct answer.

Explanation

Tubular adenoma is characterized by tubular glands with low-grade dysplasia and is a common precursor to colorectal carcinoma. Villous adenoma shows finger-like projections. Hyperplastic polyp shows serrated crypts without dysplasia. Sessile serrated lesion shows serrated crypts extending to the base and is often right-sided.

Question 36Surgical Pathology and Autopsy Pathology

A 65-year-old woman has a pancreatic head mass. Biopsy shows infiltrating glands in a desmoplastic stroma, with perineural invasion. Which diagnosis is most likely?

  1. Mucinous cystic neoplasm
  2. Serous cystadenoma
  3. Pancreatic neuroendocrine tumor
  4. Pancreatic ductal adenocarcinoma Correct answer.

Explanation

Pancreatic ductal adenocarcinoma is characterized by infiltrating glands in a desmoplastic stroma with perineural invasion and is the most common pancreatic malignancy. Neuroendocrine tumors show nests or trabeculae of uniform cells. Serous cystadenoma is a benign cystic lesion. Mucinous cystic neoplasm shows mucin-producing cysts with ovarian-type stroma.

Question 37Surgical Pathology and Autopsy Pathology

A 30-year-old man has a testicular mass. Orchiectomy shows a tumor composed of uniform cells with clear cytoplasm, distinct cell borders, and fibrous septa containing lymphocytes. Which diagnosis is most likely?

  1. Yolk sac tumor
  2. Seminoma Correct answer.
  3. Embryonal carcinoma
  4. Choriocarcinoma

Explanation

Seminoma is characterized by uniform cells with clear cytoplasm and distinct borders, separated by fibrous septa with lymphocytic infiltrate. Embryonal carcinoma shows pleomorphic cells with overlapping nuclei and necrosis. Yolk sac tumor shows Schiller-Duval bodies and reticular patterns. Choriocarcinoma shows syncytiotrophoblasts and cytotrophoblasts with hemorrhage.

Question 38Surgical Pathology and Autopsy Pathology

A 70-year-old man dies suddenly. At autopsy, the heart shows a transmural area of coagulative necrosis with a neutrophilic infiltrate and early granulation tissue at the margins. Approximately how old is the infarct?

  1. 2 to 3 weeks
  2. 12 to 24 hours
  3. 4 to 6 weeks
  4. 3 to 7 days Correct answer.

Explanation

By 3 to 7 days, a myocardial infarct shows coagulative necrosis with dense neutrophilic infiltrate and early granulation tissue at the periphery. At 12 to 24 hours, changes are subtle with wavy fibers and early neutrophilic infiltration. At 2 to 3 weeks, granulation tissue is well developed. At 4 to 6 weeks, a fibrous scar is present.

Question 39Surgical Pathology and Autopsy Pathology

A 55-year-old woman has a fine-needle aspiration of a thyroid nodule. Cytology shows papillary structures and cells with nuclear grooves and pseudoinclusions. Which diagnosis is most likely?

  1. Anaplastic carcinoma
  2. Papillary thyroid carcinoma Correct answer.
  3. Hashimoto thyroiditis
  4. Follicular adenoma

Explanation

Papillary thyroid carcinoma is characterized by papillary architecture and nuclear features including grooves, pseudoinclusions, and powdery chromatin. Follicular adenoma shows uniform follicles without these nuclear features. Hashimoto thyroiditis shows lymphocytic infiltrate and Hürthle cells. Anaplastic carcinoma shows highly pleomorphic cells and necrosis.

Question 40Surgical Pathology and Autopsy Pathology

A 60-year-old man with a history of smoking presents with hematuria. Cystoscopy shows a papillary bladder tumor. Biopsy reveals papillary fronds lined by urothelial cells with mild atypia and no invasion. Which diagnosis is most likely?

  1. Non-invasive papillary urothelial carcinoma, low grade Correct answer.
  2. Adenocarcinoma
  3. Squamous cell carcinoma
  4. Urothelial carcinoma in situ

Explanation

Non-invasive papillary urothelial carcinoma, low grade, shows papillary architecture with mild cytologic atypia and no stromal invasion. Carcinoma in situ is flat with high-grade atypia. Squamous cell carcinoma shows squamous differentiation. Adenocarcinoma shows glandular differentiation.

Question 41Surgical Pathology and Autopsy Pathology

A 45-year-old woman has a skin biopsy showing a dermal nodule of basaloid cells with peripheral palisading and retraction spaces. Which diagnosis is most likely?

  1. Dermatofibroma
  2. Basal cell carcinoma Correct answer.
  3. Melanoma
  4. Squamous cell carcinoma

Explanation

Basal cell carcinoma is characterized by nests of basaloid cells with peripheral palisading and clefting (retraction spaces) between the tumor and stroma. Squamous cell carcinoma shows keratin pearls and intercellular bridges. Melanoma shows atypical melanocytes. Dermatofibroma is a dermal spindle cell proliferation.

Question 42Surgical Pathology and Autopsy Pathology

A 50-year-old man has a colon biopsy showing crypts with basally dilated, serrated architecture extending to the base, without dysplasia. Which diagnosis is most likely?

  1. Hyperplastic polyp
  2. Traditional serrated adenoma
  3. Sessile serrated lesion Correct answer.
  4. Tubular adenoma

Explanation

Sessile serrated lesion is characterized by serrated crypts with basal dilation (boot-shaped) extending to the crypt base, often in the right colon, and is a precursor to colorectal carcinoma with BRAF mutation. Hyperplastic polyp shows serration limited to the upper crypt. Tubular adenoma shows dysplastic glands. Traditional serrated adenoma shows ectopic crypt foci and complex serration.

Question 43Surgical Pathology and Autopsy Pathology

A 35-year-old woman has a thyroid nodule. Fine-needle aspiration shows clusters of uniform follicular cells with abundant granular cytoplasm and prominent nucleoli, set in a background of lymphocytes. Which diagnosis is most likely?

  1. Hashimoto thyroiditis Correct answer.
  2. Medullary thyroid carcinoma
  3. Papillary thyroid carcinoma
  4. Follicular adenoma

Explanation

Hashimoto thyroiditis is characterized by a lymphocytic infiltrate with germinal centers and Hürthle cells (oncocytic cells with abundant granular cytoplasm and prominent nucleoli). Papillary carcinoma shows nuclear grooves and pseudoinclusions. Follicular adenoma shows uniform follicles without lymphocytic background. Medullary carcinoma shows neuroendocrine cells and amyloid.

Question 44Surgical Pathology and Autopsy Pathology

A 60-year-old woman has a lung biopsy showing a proliferation of atypical cells with prominent nucleoli and glandular formation, strongly positive for TTF-1 and napsin A. Which diagnosis is most likely?

  1. Squamous cell carcinoma
  2. Small cell carcinoma
  3. Lung adenocarcinoma Correct answer.
  4. Mesothelioma

Explanation

Lung adenocarcinoma is typically positive for TTF-1 and napsin A and shows glandular differentiation. Squamous cell carcinoma is positive for p40 and CK5/6. Small cell carcinoma shows neuroendocrine markers. Mesothelioma is positive for calretinin and WT1 and is negative for TTF-1.

Question 45Surgical Pathology and Autopsy Pathology

A 25-year-old man has a testicular mass. Serum alpha-fetoprotein is markedly elevated. Histology shows a reticular pattern with Schiller-Duval bodies. Which diagnosis is most likely?

  1. Choriocarcinoma
  2. Yolk sac tumor Correct answer.
  3. Embryonal carcinoma
  4. Seminoma

Explanation

Yolk sac tumor is characterized by elevated alpha-fetoprotein, reticular patterns, and Schiller-Duval bodies (glomeruloid structures). Seminoma does not produce alpha-fetoprotein. Embryonal carcinoma may produce hCG but not alpha-fetoprotein. Choriocarcinoma produces hCG and shows syncytiotrophoblasts and cytotrophoblasts.

Question 46Surgical Pathology and Autopsy Pathology

A 55-year-old man has a renal mass. Histology shows a tumor composed of cells with abundant eosinophilic cytoplasm and prominent nucleoli, arranged in nests. Which diagnosis is most likely?

  1. Papillary renal cell carcinoma
  2. Clear cell renal cell carcinoma
  3. Eosinophilic variant of chromophobe renal cell carcinoma Correct answer.
  4. Xp11 translocation renal cell carcinoma

Explanation

The eosinophilic variant of chromophobe renal cell carcinoma shows cells with abundant eosinophilic cytoplasm, prominent nucleoli, and a nested architecture, often with perinuclear halos. Clear cell carcinoma has clear cytoplasm. Papillary carcinoma shows papillary architecture. Xp11 translocation carcinoma shows mixed architecture and is positive for TFE3.

Question 47Surgical Pathology and Autopsy Pathology

A 60-year-old woman has a pancreatic cyst. Histology shows a cyst lined by mucinous epithelium with underlying ovarian-type stroma. Which diagnosis is most likely?

  1. Intraductal papillary mucinous neoplasm
  2. Serous cystadenoma
  3. Mucinous cystic neoplasm Correct answer.
  4. Solid pseudopapillary neoplasm

Explanation

Mucinous cystic neoplasm is defined by mucin-producing cysts with ovarian-type stroma and occurs almost exclusively in women. Intraductal papillary mucinous neoplasm communicates with the duct system and lacks ovarian-type stroma. Serous cystadenoma is lined by cuboidal cells. Solid pseudopapillary neoplasm shows solid and pseudopapillary patterns.

Question 48Surgical Pathology and Autopsy Pathology

A 70-year-old man has a bladder biopsy showing flat urothelium with marked cytologic atypia, full-thickness dysplasia, and no papillary structures. Which diagnosis is most likely?

  1. Squamous cell carcinoma
  2. Urothelial carcinoma in situ Correct answer.
  3. Non-invasive papillary urothelial carcinoma, high grade
  4. Chronic cystitis

Explanation

Urothelial carcinoma in situ is a flat lesion with high-grade cytologic atypia involving the full thickness of the urothelium. Papillary urothelial carcinoma shows papillary architecture. Squamous cell carcinoma shows squamous differentiation. Chronic cystitis shows inflammation without high-grade atypia.

Question 49Surgical Pathology and Autopsy Pathology

A 40-year-old woman has a skin biopsy of a pigmented lesion. Histology shows a proliferation of atypical melanocytes with pagetoid spread in the epidermis and nests with irregular distribution. Which diagnosis is most likely?

  1. Lentigo maligna
  2. Nodular melanoma
  3. Acral lentiginous melanoma
  4. Superficial spreading melanoma Correct answer.

Explanation

Superficial spreading melanoma is characterized by atypical melanocytes with pagetoid spread in the epidermis and irregular nests, often occurring on the trunk or extremities. Nodular melanoma shows a vertical growth phase without prominent radial spread. Lentigo maligna occurs on sun-damaged skin and shows a lentiginous proliferation. Acral lentiginous melanoma occurs on acral sites with a lentiginous pattern.

Question 50Surgical Pathology and Autopsy Pathology

A 50-year-old man has a liver biopsy showing abundant iron deposition in hepatocytes, predominantly in a periportal distribution. Which diagnosis is most likely?

  1. Wilson disease
  2. Hereditary hemochromatosis Correct answer.
  3. Alpha-1 antitrypsin deficiency
  4. Hemosiderosis secondary to multiple transfusions

Explanation

Hereditary hemochromatosis is characterized by iron deposition predominantly in periportal hepatocytes, with progression to fibrosis and cirrhosis. Secondary hemosiderosis typically shows iron in Kupffer cells. Wilson disease shows copper deposition. Alpha-1 antitrypsin deficiency shows PAS-positive globules.