Diffuse large B-cell lymphoma of the axilla clinically mimicking hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic inflammatory disease that primarily affects intertriginous areas. Its heterogeneous and sometimes nonspecific presentation can lead to diagnostic uncertainty, particularly in unilateral, treatment-resistant lesions. Cutaneous lymphomas, although rare, may mimic HS both clinically and radiologically, leading to delays in appropriate diagnosis and therapy.

A 60-year-old male presented with a 7-month history of a painful, draining axillary lesion that was initially managed as HS. Despite prolonged antibiotic and intralesional corticosteroid treatment, the lesion progressed, with increasing edema and limited arm and hand mobility. Magnetic resonance imaging revealed a multilobular mass with necrosis and matted lymph nodes. Histopathologic examination of a punch biopsy identified diffuse large B-cell lymphoma, not otherwise specified, germinal center B-cell subtype. Due to reduced ejection fraction from recent myocardial infarction, rituximab monotherapy was initiated, resulting in clinical improvement. Wound necrosis was managed with negative pressure wound therapy.

This case highlights the critical need to consider lymphomas in the differential diagnosis of atypical or refractory HS-like presentations. Prompt histopathologic evaluation in such cases enables accurate diagnosis and timely initiation of appropriate oncologic treatment, which ultimately may lead to improved patient outcomes.