Primary cutaneous follicle center lymphoma presenting as frontal fibrosing alopecia.

Overview

Primary cutaneous follicle center lymphoma rarely presents as macular alopecia and is typically characterized by solitary papules and nodules on the head, neck, and trunk. We report a 24-year-old woman with frontal alopecia that clinically resembled frontal fibrosing alopecia but was ultimately diagnosed as primary cutaneous follicle center lymphoma. The patient presented with pronounced alopecia over the left frontal scalp superimposed on milder bitemporal alopecia and intermittent symptoms of scalp irritation. Histopathologic examination of a scalp biopsy revealed a nodular lymphocytic infiltrate with irregular germinal centers localized to the adventitial dermis of the eccrine coil and the interadnexal interstitium. Immunophenotyping confirmed B-cell clonality, with findings consistent with primary cutaneous follicle center lymphoma. This case highlights the importance of biopsy in atypical alopecia presentations, as histologic findings were pivotal in diagnosing primary cutaneous follicle center lymphoma with concurrent frontal fibrosing alopecia features.