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AOBPa Pathology study materials
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AOBPa Pathology practice questions

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Question 1Anatomic Pathology

Which cellular change is the hallmark of reversible cell injury caused by mild ischemia?

  1. Deposition of dystrophic calcification
  2. Nuclear fragmentation with chromatin condensation
  3. Enzymatic digestion of the cell membrane
  4. Cellular swelling with blebbing of the plasma membrane Correct answer.

Explanation

Mild ischemia reduces ATP, impairing Na+/K+ ATPase activity and causing water influx, which produces cellular swelling and membrane blebbing; these changes reverse when blood flow is restored. Nuclear changes and membrane digestion reflect irreversible injury, and calcification is a late or chronic process.

Question 2Anatomic Pathology

A tissue section shows increased numbers of cells with preserved cell size and shape in a hyperplastic gland. Which process does this represent?

  1. Metaplasia
  2. Atrophy
  3. Hypertrophy
  4. Hyperplasia Correct answer.

Explanation

Hyperplasia is an increase in cell number, typically in tissues capable of division, and cell size and shape remain normal. Hypertrophy increases cell size, metaplasia changes cell type, and atrophy reduces tissue mass.

Question 3Anatomic Pathology

Which type of necrosis is most characteristic of an acute myocardial infarction?

  1. Fat necrosis
  2. Coagulative necrosis Correct answer.
  3. Fibrinoid necrosis
  4. Caseous necrosis

Explanation

Ischemic injury to solid organs such as the heart produces coagulative necrosis, in which tissue architecture is preserved for a time because denatured proteins block enzymatic digestion. Caseous necrosis occurs in tuberculosis, fat necrosis in pancreatitis, and fibrinoid necrosis in immune-mediated vascular injury.

Question 4Anatomic Pathology

Which cell is the principal antigen-presenting cell that activates naive T lymphocytes in lymph nodes?

  1. Dendritic cell Correct answer.
  2. Neutrophil
  3. Plasma cell
  4. Erythrocyte

Explanation

Dendritic cells capture antigen and migrate to lymph nodes, where they present peptide on MHC molecules with costimulation to activate naive T cells. Plasma cells secrete antibody, neutrophils phagocytose, and erythrocytes carry oxygen.

Question 5Anatomic Pathology

Which immunoglobulin is the principal antibody in mucosal secretions?

  1. IgG
  2. IgM
  3. IgE
  4. IgA Correct answer.

Explanation

Dimeric secretory IgA, stabilized by the J chain and secretory component, is transported across epithelium and dominates mucosal immunity. IgG is the main serum antibody, IgM is the primary early response antibody, and IgE mediates type I hypersensitivity.

Question 6Anatomic Pathology

Which feature best distinguishes malignant from benign neoplasms?

  1. Slow growth over many years
  2. Uniform cell size and shape
  3. Metastatic spread to distant sites Correct answer.
  4. Presence of a fibrous capsule

Explanation

Metastasis is the single definitive feature of malignancy, because benign tumors never metastasize. Slow growth, encapsulation, and cellular uniformity are all more typical of benign lesions.

Question 7Anatomic Pathology

Which organism is most commonly associated with chronic gastritis and gastric adenocarcinoma?

  1. Campylobacter jejuni
  2. Helicobacter pylori Correct answer.
  3. Clostridioides difficile
  4. Vibrio cholerae

Explanation

Helicobacter pylori colonizes gastric mucosa, causing chronic active gastritis and increasing risk of peptic ulcer and gastric adenocarcinoma. The other organisms cause enteric or antibiotic-associated disease rather than chronic gastritis.

Question 8Anatomic Pathology

Which vessel type is the primary site of atherosclerosis in muscular arteries?

  1. Capillaries
  2. Lymphatic vessels
  3. Large elastic and medium muscular arteries Correct answer.
  4. Venules

Explanation

Atherosclerosis affects large elastic arteries and medium-sized muscular arteries, where intimal lipid deposition and plaque formation occur. Capillaries, venules, and lymphatics are not typical sites of atheroma formation.

Question 9Anatomic Pathology

A 62-year-old man has a firm, painless nodule in the prostate. Biopsy shows crowded small glands with prominent nucleoli and no basal cell layer. Which diagnosis is most likely?

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

Explanation

Infiltrative small glands lacking a basal cell layer, together with prominent nucleoli, are features of prostatic adenocarcinoma. Benign hyperplasia retains basal cells and is glandular and stromal, prostatitis shows inflammation, and infarction shows coagulative necrosis.

Question 10Anatomic Pathology

Which pattern of inflammation is most characteristic of acute appendicitis?

  1. Lymphocytic infiltrate confined to the serosa
  2. Neutrophilic infiltration of the muscularis propria Correct answer.
  3. Noncaseating granulomas
  4. Eosinophilic infiltration of the mucosa

Explanation

Acute appendicitis is defined by neutrophilic inflammation extending into the muscularis propria, reflecting transmural acute injury. Granulomas suggest Crohn disease, eosinophils suggest allergy or parasitic infection, and isolated serosal lymphocytes are nonspecific.

Question 11Anatomic Pathology

A 45-year-old woman has a breast mass showing ducts filled with atypical cells and central necrosis with calcification. Which diagnosis fits this description?

  1. Fat necrosis
  2. Invasive ductal carcinoma
  3. Fibroadenoma
  4. Ductal carcinoma in situ Correct answer.

Explanation

Atypical cells confined within ducts, with central comedo necrosis and calcification, define ductal carcinoma in situ. Fibroadenoma is a benign biphasic lesion, invasive carcinoma breaches the duct, and fat necrosis shows lipid-laden macrophages.

Question 12Anatomic Pathology

A patient with chronic hepatitis B develops a liver mass with trabeculae of hepatocytes, increased nuclear-to-cytoplasmic ratio, and vascular invasion. Which tumor is most likely?

  1. Hepatocellular carcinoma Correct answer.
  2. Focal nodular hyperplasia
  3. Hepatic hemangioma
  4. Hepatocellular adenoma

Explanation

Trabecular architecture, atypia, and vascular invasion in a cirrhotic or chronically infected liver indicate hepatocellular carcinoma. Adenoma and focal nodular hyperplasia are benign, and hemangioma is a vascular lesion.

Question 13Anatomic Pathology

A 70-year-old smoker has a central lung mass with keratin pearls and intercellular bridges. Which histologic type is present?

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

Explanation

Keratin pearls and intercellular bridges are features of squamous differentiation, and squamous cell carcinoma typically arises centrally in smokers. Adenocarcinoma is usually peripheral and glandular, small cell carcinoma shows crush artifact and neuroendocrine markers, and carcinoid has uniform nests.

Question 14Anatomic Pathology

Which renal lesion is characterized by a proliferation of mesangial cells and matrix in a patient with IgA nephropathy?

  1. Membranous nephropathy
  2. Mesangioproliferative glomerulonephritis Correct answer.
  3. Minimal change disease
  4. Amyloidosis

Explanation

IgA nephropathy produces mesangial deposition of IgA with mesangial cell and matrix proliferation. Membranous nephropathy shows subepithelial deposits, minimal change disease has normal light microscopy, and amyloidosis shows amorphous deposits.

Question 15Anatomic Pathology

A 55-year-old woman has a thyroid nodule showing papillary structures with optically clear nuclei and nuclear grooves. Which diagnosis is correct?

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

Explanation

Papillary architecture with optically clear (Orphan Annie) nuclei and nuclear grooves is diagnostic of papillary thyroid carcinoma. Follicular adenoma lacks these nuclear features, medullary carcinoma shows amyloid and calcitonin, and Hashimoto thyroiditis shows lymphocytic inflammation.

Question 16Anatomic Pathology

Which type of hypersensitivity reaction mediates acute hemolytic transfusion reactions?

  1. Type III
  2. Type IV
  3. Type I
  4. Type II Correct answer.

Explanation

Acute hemolytic transfusion reactions are type II antibody-mediated reactions in which preformed antibodies bind donor red cell antigens and cause complement-mediated lysis. Type I is IgE-mediated, type III is immune complex-mediated, and type IV is T cell-mediated.

Question 17Anatomic Pathology

Which feature indicates irreversible myocardial injury on histology?

  1. Fatty change
  2. Cellular swelling
  3. Contraction band necrosis with loss of nuclei Correct answer.
  4. Interstitial edema

Explanation

Loss of nuclei and contraction band necrosis reflect irreversible injury and cell death after prolonged ischemia. Swelling, fatty change, and edema are reversible or nonspecific findings.

Question 18Anatomic Pathology

A biopsy of a colonic polyp shows elongated, hyperchromatic nuclei with a sawtooth arrangement. Which lesion is described?

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

Explanation

Sawtooth crypts with dilated bases and elongated hyperchromatic nuclei characterize sessile serrated lesions, which carry a distinct neoplastic pathway. Hyperplastic polyps have smaller straight crypts, tubular adenomas show dysplastic epithelium, and adenocarcinoma invades the submucosa.

Question 19Anatomic Pathology

Which mechanism best explains the increased risk of thrombosis in a patient with a factor V Leiden mutation?

  1. Increased platelet aggregation
  2. Resistance of factor Va to activated protein C Correct answer.
  3. Deficiency of antithrombin III
  4. Deficiency of von Willebrand factor

Explanation

Factor V Leiden alters factor V so that activated protein C cannot cleave it, producing a hypercoagulable state. Antithrombin deficiency is a separate disorder, von Willebrand deficiency causes bleeding, and platelet aggregation is not the mechanism.

Question 20Anatomic Pathology

A 30-year-old man has lymphadenopathy showing Reed-Sternberg cells with CD15 and CD30 positivity. Which diagnosis is most likely?

  1. Follicular lymphoma
  2. Hodgkin lymphoma Correct answer.
  3. Burkitt lymphoma
  4. Chronic lymphocytic leukemia

Explanation

Reed-Sternberg cells with CD15 and CD30 expression are the diagnostic hallmark of classic Hodgkin lymphoma. Follicular lymphoma shows follicle center cells, CLL shows small mature lymphocytes, and Burkitt lymphoma shows a starry-sky pattern with MYC translocation.

Question 21Anatomic Pathology

Which feature most strongly indicates a poor prognosis in a resected melanoma?

  1. Presence of a benign nevus
  2. Superficial spreading growth pattern
  3. Breslow thickness greater than 4 mm Correct answer.
  4. Absence of ulceration

Explanation

Increasing Breslow thickness, especially greater than 4 mm, correlates with higher risk of metastasis and death. A benign nevus, superficial spreading pattern, and absence of ulceration are relatively favorable features.

Question 22Anatomic Pathology

A lung biopsy shows noncaseating granulomas with Langhans giant cells and a negative stain for organisms. Which condition is most consistent with these findings?

  1. Pulmonary embolism
  2. Bronchopneumonia
  3. Emphysema
  4. Sarcoidosis Correct answer.

Explanation

Noncaseating granulomas with Langhans giant cells and no identifiable organism suggest sarcoidosis, a granulomatous disease of unknown cause. Bronchopneumonia is suppurative, embolism shows infarction or thrombus, and emphysema shows alveolar destruction.

Question 23Anatomic Pathology

Which molecular abnormality is most characteristic of chronic myeloid leukemia?

  1. BCR-ABL1 fusion Correct answer.
  2. TP53 deletion
  3. JAK2 V617F mutation
  4. t(14;18) translocation

Explanation

Chronic myeloid leukemia is defined by the Philadelphia chromosome, a t(9;22) translocation producing the BCR-ABL1 fusion tyrosine kinase. JAK2 V617F occurs in myeloproliferative neoplasms other than CML, t(14;18) occurs in follicular lymphoma, and TP53 deletion is common in CLL.

Question 24Anatomic Pathology

A renal biopsy shows crescents filling Bowman space with fibrin and parietal epithelial proliferation. Which process does this indicate?

  1. Minimal change disease
  2. Nephrolithiasis
  3. Chronic pyelonephritis
  4. Rapidly progressive glomerulonephritis Correct answer.

Explanation

Crescents composed of proliferating parietal epithelial cells, monocytes, and fibrin indicate severe glomerular injury with rupture of the capillary wall, characteristic of rapidly progressive glomerulonephritis. Minimal change disease has normal light microscopy, pyelonephritis shows tubulointerstitial inflammation, and stones are luminal calculi.

Question 25Anatomic Pathology

Which sequence best describes the multistep pathogenesis of colorectal carcinoma arising from an adenoma?

  1. BCL2 translocation, then MYC amplification, then APC loss
  2. KRAS mutation, then TP53 loss, then APC loss
  3. APC loss, then KRAS mutation, then TP53 loss Correct answer.
  4. TP53 loss, then APC loss, then KRAS mutation

Explanation

The classic adenoma-carcinoma sequence begins with loss of APC, followed by activating KRAS mutation and later loss of TP53 as dysplasia progresses to invasion. The other orders invert this established sequence or invoke abnormalities not typical of this pathway.

Question 26Anatomic Pathology

Which cellular adaptation is best described as an increase in the number of cells in a tissue in response to stress?

  1. Atrophy
  2. Metaplasia
  3. Hyperplasia Correct answer.
  4. Hypertrophy

Explanation

Hyperplasia is an increase in cell number, typically occurring in tissues capable of mitotic division. Hypertrophy is an increase in cell size, metaplasia is a change from one differentiated cell type to another, and atrophy is a decrease in cell size or number.

Question 27Anatomic Pathology

A tissue normally lined by stratified squamous epithelium is chronically irritated and is replaced by mucus-secreting columnar cells. Which term best describes this change?

  1. Metaplasia Correct answer.
  2. Hyperplasia
  3. Anaplasia
  4. Dysplasia

Explanation

Metaplasia is a reversible substitution of one mature epithelial type for another, often as an adaptation to chronic irritation. The change is not dysplasia, which involves disordered maturation, nor anaplasia, which denotes lack of differentiation in malignancy.

Question 28Anatomic Pathology

Which type of cell death is characterized by cell swelling, membrane rupture, and an associated inflammatory response?

  1. Autophagy
  2. Apoptosis
  3. Necrosis Correct answer.
  4. Senescence

Explanation

Necrosis is an uncontrolled form of cell death marked by swelling, membrane disruption, and leakage of contents that provokes inflammation. Apoptosis is an energy-dependent, non-inflammatory process with cell shrinkage and membrane-bound bodies.

Question 29Anatomic Pathology

Which pigment accumulates in the skin and sclera in a patient with impaired hepatic conjugation of bilirubin?

  1. Melanin
  2. Hemosiderin
  3. Lipofuscin
  4. Bilirubin Correct answer.

Explanation

Bilirubin is a yellow pigment derived from heme catabolism, and its accumulation produces jaundice with yellowing of skin and sclera. Hemosiderin is an iron-storage pigment, lipofuscin is a wear-and-tear pigment, and melanin is a brown-black pigment of melanocytes.

Question 30Anatomic Pathology

Which process is the primary mechanism by which neutrophils leave the bloodstream to reach a site of acute inflammation?

  1. Diapedesis through endothelial junctions Correct answer.
  2. Opsonization by complement
  3. Phagocytosis of bacteria in the lumen
  4. Degranulation of mast cells

Explanation

Neutrophils marginate, adhere to endothelium, and then migrate through interendothelial junctions by diapedesis to enter the tissue. Phagocytosis, opsonization, and mast-cell degranulation occur after or independently of this transmigration step.

Question 31Anatomic Pathology

Which cell type is the principal source of collagen in a healing wound during granulation tissue formation?

  1. Macrophages
  2. Neutrophils
  3. Endothelial cells
  4. Fibroblasts Correct answer.

Explanation

Fibroblasts migrate into the wound and synthesize collagen and other extracellular matrix components that form the granulation tissue scaffold. Macrophages and neutrophils are inflammatory cells, and endothelial cells form new vessels.

Question 32Anatomic Pathology

Which type of embolism most commonly travels to the lungs?

  1. Fat embolism after long-bone fracture
  2. Arterial thromboembolism from the left ventricle
  3. Venous thromboembolism Correct answer.
  4. Amniotic fluid embolism

Explanation

Thrombi formed in the venous system embolize through the right heart and lodge in the pulmonary arterial tree. Emboli from the left heart or aorta travel to systemic arteries, and fat and amniotic fluid emboli are distinct, less common entities.

Question 33Anatomic Pathology

Which immunoglobulin class is most abundant in normal serum?

  1. IgA
  2. IgM
  3. IgE
  4. IgG Correct answer.

Explanation

IgG constitutes roughly 75 to 80 percent of serum immunoglobulins and provides the main systemic humoral defense. IgA predominates in secretions, IgM is the first antibody in primary responses, and IgE is present in trace amounts.

Question 34Anatomic Pathology

A patient with a chronic inflammatory condition develops amyloid deposition. Which stain classically produces apple-green birefringence under polarized light?

  1. Congo red Correct answer.
  2. Periodic acid-Schiff
  3. Prussian blue
  4. Masson trichrome

Explanation

Congo red binds amyloid fibrils and yields apple-green birefringence when viewed under polarized light. Prussian blue stains iron, PAS stains glycogen and mucin, and trichrome highlights collagen and muscle.

Question 35Anatomic Pathology

A 60-year-old man with long-standing hypertension dies suddenly. At autopsy the left ventricular wall is markedly thickened without chamber dilation. Which adaptation best accounts for this finding?

  1. Fatty infiltration
  2. Left ventricular dilation
  3. Left ventricular hypertrophy Correct answer.
  4. Myocardial hyperplasia

Explanation

Pressure overload from hypertension causes cardiomyocytes to enlarge, producing concentric ventricular hypertrophy without chamber dilation. Cardiomyocytes have limited proliferative capacity, so hyperplasia is not the mechanism.

Question 36Anatomic Pathology

A 28-year-old woman has recurrent infections and is found to have defective phagocyte oxidative burst. Which enzyme is most likely deficient?

  1. Myeloperoxidase
  2. Superoxide dismutase
  3. Catalase
  4. NADPH oxidase Correct answer.

Explanation

Chronic granulomatous disease results from defects in NADPH oxidase, which generates superoxide for the respiratory burst. Myeloperoxidase deficiency impairs hypochlorite generation but usually causes milder disease, and the other enzymes are antioxidant or detoxifying.

Question 37Anatomic Pathology

A 50-year-old woman has a malar rash, photosensitivity, and autoantibodies against double-stranded DNA. Which type of hypersensitivity reaction underlies her tissue injury?

  1. Type III immune complex-mediated hypersensitivity Correct answer.
  2. Type II antibody-mediated hypersensitivity
  3. Type IV T-cell-mediated hypersensitivity
  4. Type I immediate hypersensitivity

Explanation

Systemic lupus erythematosus causes injury largely through deposition of circulating immune complexes in tissues such as skin, kidney, and vessels, a type III reaction. Type II reactions involve antibodies directed at fixed tissue antigens, and type IV is cell-mediated.

Question 38Anatomic Pathology

A 35-year-old man develops a painless chancre that heals, and years later has ascending aortic dilation with aortitis. Which organism is responsible?

  1. Treponema pallidum Correct answer.
  2. Haemophilus ducreyi
  3. Chlamydia trachomatis
  4. Neisseria gonorrhoeae

Explanation

Tertiary syphilis caused by Treponema pallidum classically produces aortitis with dilation of the ascending aorta. The other organisms cause different genital or systemic infections without this characteristic late vascular lesion.

Question 39Anatomic Pathology

A 65-year-old man has a slowly enlarging, well-circumscribed firm nodule in the subcutaneous tissue of the back. Histology shows a uniform proliferation of spindle cells with abundant collagen and low mitotic activity. Which lesion is most likely?

  1. Liposarcoma
  2. Metastatic carcinoma
  3. Fibrosarcoma
  4. Fibroma Correct answer.

Explanation

A well-circumscribed, hypocellular spindle-cell lesion with abundant collagen and low mitotic activity is characteristic of a benign fibrous lesion such as a fibroma. Sarcomas and carcinomas show atypia, infiltrative growth, or epithelial features.

Question 40Anatomic Pathology

A 40-year-old woman has a thyroid mass with a follicular growth pattern. Capsular invasion is identified on careful sectioning without vascular invasion. Which diagnosis is most appropriate?

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

Explanation

Follicular carcinoma is distinguished from follicular adenoma by capsular or vascular invasion; demonstration of capsular invasion establishes malignancy. Papillary and medullary carcinomas have different nuclear and cell features, respectively.

Question 41Anatomic Pathology

A patient with a bleeding ulcer undergoes endoscopy and biopsy. Which histologic finding most directly indicates active recent hemorrhage?

  1. Hematin pigment within the ulcer base Correct answer.
  2. Hemosiderin-laden macrophages in the base
  3. Granulation tissue with capillaries
  4. Fibrinoid necrosis of vessel walls

Explanation

Hematin, an acid hematin pigment formed from digested blood, accumulates in the ulcer base after hemorrhage and marks recent bleeding. Hemosiderin reflects older hemorrhage, granulation tissue indicates healing, and fibrinoid necrosis is a vascular injury pattern.

Question 42Anatomic Pathology

A 55-year-old man with cirrhosis develops ascites and dilated abdominal veins. Which hemodynamic change best explains these findings?

  1. Increased hepatic venous outflow
  2. Reduced sinusoidal resistance
  3. Decreased splanchnic blood flow
  4. Increased portal venous pressure Correct answer.

Explanation

Cirrhosis increases intrahepatic resistance and portal pressure, producing portal hypertension with ascites and portosystemic collaterals. Reduced sinusoidal resistance or increased hepatic venous outflow would lower rather than raise portal pressure.

Question 43Anatomic Pathology

A 62-year-old woman has a pigmented skin lesion with irregular borders and a radial growth phase of atypical melanocytes confined to the epidermis. Which term describes this early stage?

  1. Melanoma in situ Correct answer.
  2. Blue nevus
  3. Metastatic melanoma
  4. Nodular melanoma

Explanation

Atypical melanocytes confined to the epidermis constitute melanoma in situ, a radial growth phase lesion without dermal invasion. Nodular melanoma shows vertical growth, metastatic melanoma involves distant sites, and a blue nevus is a benign dermal melanocytic lesion.

Question 44Anatomic Pathology

A 48-year-old man has painless gross hematuria. Cystoscopy shows a papillary bladder mass composed of fibrovascular cores lined by urothelium with mild atypia. Which lesion is most likely?

  1. Invasive urothelial carcinoma
  2. Urothelial papilloma Correct answer.
  3. Squamous cell carcinoma of the bladder
  4. Nephrogenic adenoma

Explanation

A papillary lesion with delicate fibrovascular cores and orderly urothelium lacking significant atypia is a urothelial papilloma. Invasive carcinoma shows invasion, and squamous carcinoma shows keratinizing malignant cells.

Question 45Anatomic Pathology

A 70-year-old woman has a distal femoral lesion with a sunburst periosteal reaction and a destructive medullary mass. Which primary bone tumor is most likely?

  1. Osteosarcoma Correct answer.
  2. Osteochondroma
  3. Giant cell tumor
  4. Ewing sarcoma

Explanation

Osteosarcoma typically arises in the metaphysis of long bones in older adults or adolescents and produces aggressive periosteal reactions such as sunburst patterns. Osteochondroma is a benign exostosis, Ewing sarcoma favors the diaphysis of children, and giant cell tumor involves the epiphysis.

Question 46Anatomic Pathology

A 30-year-old woman has a cystic ovarian mass lined by ciliated columnar epithelium with fallopian tube-like differentiation. Which diagnosis is most likely?

  1. Endometrioma
  2. Mucinous cystadenoma
  3. Teratoma
  4. Serous cystadenoma Correct answer.

Explanation

Serous cystadenomas are lined by ciliated columnar epithelium resembling the fallopian tube. Mucinous tumors have mucin-secreting epithelium, endometriomas contain endometrial tissue and blood, and teratomas show multiple germ-layer elements.

Question 47Anatomic Pathology

A 58-year-old man has a pancreatic head mass causing obstructive jaundice. Histology shows infiltrative glands with desmoplasia in a background of chronic pancreatitis. Which feature best supports malignancy over chronic pancreatitis?

  1. Fibrosis
  2. Lymphocytic infiltrate
  3. Perineural invasion Correct answer.
  4. Acinar atrophy

Explanation

Perineural invasion by neoplastic glands is a strong indicator of invasive pancreatic adenocarcinoma. Fibrosis, inflammation, and acinar atrophy occur in chronic pancreatitis and are not by themselves diagnostic of malignancy.

Question 48Anatomic Pathology

A 45-year-old man has a testicular mass. Histology shows uniform cells with clear cytoplasm, distinct membranes, and fibrous septa containing lymphocytes. Which tumor is most likely?

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

Explanation

Seminoma is composed of uniform cells with clear cytoplasm and well-defined borders, partitioned by fibrous septa with lymphocytic infiltrates. Embryonal and yolk sac tumors show more pleomorphism or specific patterns such as Schiller-Duval bodies.

Question 49Anatomic Pathology

A 68-year-old man with a history of prostate cancer presents with a vertebral lesion. Histology shows glands with prominent nucleoli and positive immunohistochemistry for prostate-specific antigen. Which mechanism best explains this lesion?

  1. Implantation during surgery
  2. Direct extension from the prostate
  3. Hematogenous metastasis to bone Correct answer.
  4. Lymphatic spread to para-aortic nodes

Explanation

Prostate carcinoma characteristically spreads hematogenously to the axial skeleton, often via the vertebral venous plexus. The presence of PSA-positive glands in bone indicates metastatic carcinoma rather than local extension or nodal disease.

Question 50Anatomic Pathology

A 52-year-old woman has a renal mass. Histology shows nests of cells with abundant clear cytoplasm and a delicate vascular network. Which translocation is most characteristically associated with this tumor?

  1. t(X;1) involving PRCC
  2. t(3;8) involving VHL Correct answer.
  3. t(6;11) involving TFEB
  4. t(12;16) involving FUS

Explanation

Clear cell renal cell carcinoma is strongly associated with inactivation of the VHL gene on chromosome 3p, sometimes through translocations involving chromosome 3. The other translocations are linked to different tumor types such as translocation renal cell carcinoma or myxoid liposarcoma.