Follicular mycosis fungoides. A clinical and histologic variant of cutaneous T-cell lymphoma: report of two cases.

We report two cases of mycosis fungoides with marked, pleomorphic follicular manifestations. Follicular hyperkeratosis, comedo-like lesions, acquired epidermal cysts, and patchy alopecia developed in various locations in both patients. Findings of histopathologic and immunohistochemical studies showed atypical CD4+ T lymphocytes infiltrating the follicles without follicular mucinosis. Focal expression of intercellular adhesion molecule type 1 was observed within the cyst walls. These findings suggest that the follicular lesions were specific for mycosis fungoides. These manifestations represent a distinct clinical and histologic form of mycosis fungoides. This variant probably accounts for cases of mycosis fungoides with clinically suspected alopecia mucinosa in which follicular mucinosis cannot be histologically proved.