Abstract

An 85-year-old male with a history of insulin dependent diabetes mellitus and peripheral vascular disease presented with a 3-month history of a right mandibular ulcer. The lesion began as a pustule for which he received a course of amoxicillin with no improvement. He reported rapid growth of the pustule after a biopsy at an outside institution. At presentation, the patient underwent two fine needle aspirations (FNA) and one core biopsy showing a mixed inflammatory infiltrate and granulation tissue. One FNA showed rare, atypical epithelioid cells, but due to their scarcity, they could not be further characterized. Given the lack of response to antibiotics and negative tissue cultures, worsening with trauma, and nonspecific biopsy findings, the patient was diagnosed with pyoderma gangrenosum (PG) and was treated with prednisone and adalimumab. Several days after beginning adalimumab, the ulcer became more edematous and, after 1-month of treatment, he developed odynophagia prompting inpatient admission. Given the rapid growth despite corticosteroids, immunglobulins, and infliximab, a punch biopsy from the ulcer edge was done. The biopsy demonstrated a diffuse infiltrate of pleomorphic epithelioid cells with numerous atypical mitotic figures. Initial immunohistochemistry (IHC) for CD45 and CD30 was diffusely positive in the atypical cells and negative for CD3, SOX-10 and pancytokeratin. Large pleomorphic CD30+ lymphoid cells pointed towards a diagnosis of anaplastic large cell lymphoma (ALCL). Additional IHC was negative for CD2, CD4, CD8, and CD56. Instead, most of the atypical cells were highlighted by CD20, CD79a and Epstein Barr virus (EBV). Further work up supported a diagnosis of EBV+ diffuse large B-cell lymphoma not otherwise specified. This case highlights the pitfalls of FNA and core biopsies in the work up for PG. Furthermore, while CD30 expression in cutaneous lymphomas is associated with ALCL, work up should remain broad to evaluate for other lymphomas.

Financial Disclosure:
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