Track

Case Reports

Abstract

Hidradenitis suppurativa (HS) is a chronic, inflammatory skin disease typified by repeated formation of painful nodules, abscesses, and sinus tracts. Within the last decade, treatment options have expanded to include biologics (adalimumab) and small molecule inhibitors. Although effective, anti–TNF-α therapies may carry increased risks of infection and malignancy. Hairy cell leukemia (HCL) is a rare indolent B-cell malignancy not previously associated with adalimumab use.

We report the case of a 67-year-old male with treatment-resistant HS who developed persistent leukopenia and febrile illness following initiation of adalimumab. Initially, the cytopenias were attributed to immunosuppression; however, further investigation revealed peripheral blood smear and bone marrow findings diagnostic of HCL.

This case illustrates a diagnostic dilemma in distinguishing drug-related cytopenias from underlying hematologic malignancy. While the association between TNF-α inhibitors and lymphoid neoplasms remains controversial, this case raises the possibility of unmasking or accelerating subclinical disease via immune modulation. The potential interplay between chronic inflammation, TNF-α signaling, and BRAF-mutated clonal expansion warrants further investigation.