Subcutaneous mass concerning for sarcoma: a peculiar presentation of diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) can present in a number of different ways, including as a primary cutaneous lesion or at various other extranodal sites. However, it is rare for a DLBCL to present as a clinically subcutaneous mass without visible skin changes or nodal involvement. A 36-year-old man presented with a 4×4×1 cm subcutaneous mass to his shoulder with normal overlying skin which had been enlarging over 6 months. Physical exam and imaging together made a strong case for sarcoma, and the patient underwent a radical resection. The final pathological diagnosis returned as a diffuse B-cell lymphoma (germinal centre type). The patient subsequently healed and tolerated chemotherapy well. DLBCL can masquerade as a soft tissue mass at initial presentation. If the diagnosis is not clear, a biopsy should be pursued.