Presentation of Cutaneous Large B-Cell Lymphoma, Leg Type

Description A 91-year-old man presented with 2 violaceous, ulcerated plaques on his left lower leg, which developed over a 4-month period following a fall. The patient reported the initial formation of a solitary lump, which gradually enlarged and began bleeding a few weeks before his clinic visit. A histological examination of 2 biopsy samples revealed a dermal proliferation of large, severely atypical lymphoid cells with mitotic figures. Immunohistochemistry showed positivity for CD20, Bcl2, Bcl6, and MUM1, with cytokeratin 20 (CK20) negativity and a high percentage (80%-90%) of C-MYC positivity, which was consistent with a primary cutaneous diffuse large B-cell lymphoma (PCDLBC-LT). Given the findings, the patient was referred to oncology for further management.