June 1, 2021
Diagnose This (May 31, 2021)
This is a CD20 immunohistochemical stain. Knowing that these cells are mostly within peritubular capillaries, what is your diagnosis?
This is an intravascular large B-cell lymphoma (LBCL), which is a rare type of LBCL that is characterized by the presence of neoplastic B cells limited to the lumen of small vessels. This is likely secondary to their lack of expression of surface proteins that allow transvascular migration. Malignant B cells are only rarely present in peripheral blood (5%) or bone marrow. The patient also had pituitary enlargement, adrenal insufficiency, and anemia, for which a bone marrow biopsy was performed with negative results. The diagnosis was established through a renal biopsy performed due to elevated serum creatinine. Urine sediment was unremarkable.
Low power image