A 48-year-old woman, who had an outside diagnosis of “peripheral T-cell lymphoma” based on a needle biopsy of a peripancreatic lesion 10 months before, presented with hypercalcemia (15.3 mg/dL) and metabolically active lymphadenopathy after receiving 6 cycles of CHOEP (cyclophosphamide, doxorubicin, vincristine, etoposide, and prednisone) and BEAM (carmustine, etoposide, cytarabine, and melphalan) myeloablative therapy with autologous stem cell transplantation. A few months after her initial workup, she was found to have positive human T-cell leukemia virus type 1 (HTLV-1)/HTLV-2 antibody testing. A bone marrow biopsy was performed given the clinical concern for disease relapse. The core biopsy showed a 50% cellular marrow with a focal loose paratrabecular aggregate (panel A, circle; hematoxylin and eosin stain, original magnification ×20) composed of histiocytes, plasma cells, small lymphocytes, and highly pleomorphic large atypical cells with deeply convoluted nuclei (panels A-B; hematoxylin and eosin stain, original magnification ×40 [B]). Some pleomorphic cells were individually infiltrating in an interstitial fashion. The pleomorphic cells were positive for CD3, CD25 (panels C-D; immunohistochemistry stain, original magnification ×40), and CD4 and negative for CD5 and CD8 by immunohistochemistry. Around the aggregate, there was osteoclastic, bone-chewing activity (arrows). Polymerase chain reaction confirmed the presence of HTLV-1. Thus, a diagnosis of adult T-cell leukemia/lymphoma (ATLL) was rendered.
This case clearly illustrates the characteristic morphology and clinicopathologic correlation of hypercalcemia and bone destruction. Osteolytic bone resorption is a very common phenomenon in ATLL, which likely results in hypercalcemia in this rare aggressive neoplasm.