Follicular mucinosis: histopathologic review of 33 cases.

Among 33 patients with the histologic diagnosis of follicular mucinosis (alopecia mucinosa) made at our institution between 1982 and 1989, 9 had mycosis fungoides diagnosed concomitantly. Three other patients had lymphoproliferative disorders, and two had Kaposi's sarcoma. Analysis of biopsy features such as epidermal lymphocytic exocytosis, periappendageal infiltrate, and deposition of mucin revealed no predominant finding that distinguished a benign course from mycosis fungoides. A predominance of eosinophils in the infiltrate was suggestive of benign follicular mucinosis rather than mycosis fungoides. Gene rearrangement studies detected three clones in three patients with follicular mucinosis; two were in patients with mycosis fungoides, and one was in a patient with dermatitis. The outcome of these three patients is pending further follow-up. No histopathologic or clinical features distinguished these patients from the others.