Anatomic and Clinical Pathology Flashcards

A surgical pathology specimen from a 50-year-old smoker shows a lung tumor with cells arranged in nests ('Zellballen') and expressing synaptophysin and chromogranin on immunohistochemistry. What is this tumor?

Answer: Carcinoid tumor (neuroendocrine tumor)

Carcinoid tumors are well-differentiated neuroendocrine neoplasms that grow in organoid nests and are positive for neuroendocrine markers synaptophysin and chromogranin.

A 35-year-old woman has elevated serum ALT, AST, and anti-smooth muscle antibody titer of 1:320. Liver biopsy shows interface hepatitis with plasma cell infiltration. What is the diagnosis?

Answer: Autoimmune hepatitis

Autoimmune hepatitis features interface hepatitis, plasma cell-rich inflammation, and positive autoantibodies including anti-smooth muscle antibody.

On electron microscopy of a glomerulus, subepithelial electron-dense deposits with a 'spike and dome' appearance are seen. What disease does this represent?

Answer: Membranous nephropathy

Membranous nephropathy shows subepithelial immune deposits with reactive GBM spikes forming between deposits, creating the classic 'spike and dome' pattern on EM.

A 55-year-old male has a skin lesion on the back showing a melanocytic proliferation with asymmetry, irregular borders, color variation, and a diameter of 8 mm. The Breslow thickness is 1.8 mm. What does Breslow thickness determine?

Answer: Depth of tumor invasion from the granular layer or ulcer base, used for staging and prognosis

Breslow thickness measures the vertical depth of melanoma from the granular cell layer (or ulcer base) to the deepest tumor cell, and is the primary prognostic factor.

A serum protein electrophoresis shows a sharp, narrow peak in the gamma region. The next best step to characterize this finding is:

Answer: Serum immunofixation electrophoresis to identify the heavy and light chain class

Immunofixation electrophoresis identifies and characterizes the specific immunoglobulin class (e.g., IgG kappa) of an M-spike detected on SPEP.

A 28-year-old woman has recurrent miscarriages and thromboses. Laboratory testing shows prolonged aPTT that does not correct with 1:1 mixing with normal plasma. What does failure to correct with mixing suggest?

Answer: Presence of an inhibitor (antibody) rather than a factor deficiency

Failure of the prolonged aPTT to correct with normal plasma mixing indicates the presence of an inhibitor (such as lupus anticoagulant), not a factor deficiency.

A 65-year-old male has a renal mass removed surgically. Histology shows clear cells arranged in nests with a rich vascular network. Immunohistochemistry shows positivity for CD10 and PAX8 and negativity for CK7. What is the diagnosis?

Answer: Clear cell renal cell carcinoma

Clear cell RCC shows clear cytoplasm due to glycogen and lipid accumulation, is CD10+ and PAX8+, and typically CK7-negative, distinguishing it from papillary and chromophobe RCC.