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Question #152 (7/10/2026)

National Association of Medical Examiners 
Educational Activities Committee

Submitted by Dr. Alissa Schurr, (PGY-3, Thomas Jefferson University Hospital, Philadelphia, PA), Dr. Jiayi “Grace” Li, (PGY-2, Thomas Jefferson University Hospital, Philadelphia, PA), and Dr. Steven Schwartz, (Faculty neuropathologist and Director of Autopsy, Thomas Jefferson University Hospital, Philadelphia, PA).
High-power view of lung parenchyma, H&E 400x
Glomeruli, H&E 200x
Peri-testicular tissue, H&E 200x
Pituitary gland, H&E 200x
1.The decedent was an 80 year‑old male with past medical history of borderline HTN, prior TIA, osteoarthritis, and a 15-20 pk-yr smoking history. He initially presented to the hospital with progressive shortness of breath, fatigue, poor appetite, and weight loss over the course of months. During his hospital stay, he developed fevers, thrombocytopenia, and acute kidney injury. An extensive rheumatologic, infectious, and hematologic workup (including bone marrow biopsy) was unrevealing, except for some elevated nonspecific inflammatory markers. His fevers continued despite broad-spectrum antibiotic coverage. His clinical status continued to decline with interval development of transaminitis, hyperuricemia, markedly elevated LDH, and ongoing coagulopathy. Eventually, the patient developed multiorgan failure and was transitioned to comfort care. Autopsy was requested after the patient expired.

Notable labs/pathology prior to his death are as follows:

C-Reactive Protein: 12.64 mg/dL (reference range, ≤ 0.80 mg/dL)
Lactate Dehydrogenase: 2,380 IU/L (reference range, 125-240 IU/L)
Interleukin-2 Receptor: 30,600 pg/mL (reference range, 532-1891 pg/mL)
Protime: 26.9 sec (reference range, 9.4-13.0 sec)
Partial Thromboplastin Time: 51 sec (reference range, 25-37 sec)
Fibrinogen: 423 mg/dL (reference range, 200-393 mg/dL)
International Normalized Ratio: 2.40 INR (reference range, 0.87-1.19 INR)
D-dimer: 1,921 ng/mL DDU (reference range, ≤ 243 ng/mL DDU)

Autopsy revealed mild cardiomegaly, severe atherosclerosis, bilateral pleural effusions, pulmonary edema, and splenomegaly (Figure 1, weight 970 g). Focal hepatic and splenic infarcts were noted. A congealed yellow-white mucoid material consistent with fibrin deposition was noted within the left mainstem bronchus and right cardiac ventricle. No lymphadenopathy was identified grossly. Representative sections of each organ were collected; cells with atypical morphology were noted within the small vasculature of most organs, including in immune-privileged areas(testes, brain, etc.). Photomicrographs of selected organs are shown.

Based on the expected immunophenotype of the disease entity, which of the following IHC markers will be most likely be NEGATIVE in the cells with atypical morphology?