NBME Pathology 3

Question 1

A 60-year-old smoker develops Cushing syndrome without an adrenal or pituitary cause. Chest CT reveals a central hilar mass. What is the tumor type?

Accepted Answer

Small cell (oat cell) carcinoma

Answer

Small cell carcinoma of the lung is a neuroendocrine tumor that frequently secretes ACTH ectopically, causing paraneoplastic Cushing syndrome.

Question 2

A biopsy of a lymph node shows Reed-Sternberg cells with an 'owl-eye' appearance. Flow cytometry shows CD15+/CD30+/CD45- cells. What is the diagnosis?

Accepted Answer

Classic Hodgkin lymphoma

Answer

Classic Hodgkin lymphoma Reed-Sternberg cells are CD15+, CD30+, and characteristically CD45- (leukocyte common antigen negative).

Question 3

A 45-year-old woman presents with symmetric joint pain, morning stiffness >1 hour, and subcutaneous nodules. Serology shows anti-CCP antibodies. Which pathological process drives joint destruction?

Accepted Answer

Pannus formation with enzymatic erosion of cartilage and bone

Answer

In rheumatoid arthritis, synovial hyperplasia forms pannus tissue containing proteases and osteoclast-activating cytokines that erode cartilage and bone.

Question 4

A 35-year-old man with hemoptysis has a chest X-ray showing bilateral pulmonary infiltrates. Urine shows hematuria. Immunofluorescence of kidney biopsy reveals linear IgG deposits along the GBM. What is the antigen?

Accepted Answer

Type IV collagen alpha-3 chain (Goodpasture antigen)

Answer

Goodpasture syndrome results from autoantibodies targeting the alpha-3 chain of type IV collagen in both glomerular and alveolar basement membranes.

Question 5

A 70-year-old woman has a lytic skull lesion, hypercalcemia, anemia, and rouleaux formation on peripheral smear. Urine protein electrophoresis shows a Bence Jones protein. Which cells are malignant?

Accepted Answer

Plasma cells

Answer

Multiple myeloma is a malignancy of terminally differentiated plasma cells that produce monoclonal immunoglobulin (M protein) and free light chains (Bence Jones proteins).

NBME Practice Test

NBME Practice Test

NBME Pathology 3