Syringotropic Mycosis Fungoides: A Rare Variant of the Disease With Peculiar Clinicopathologic Features

A rare variant of mycosis fungoides (MF) characterized by prominent involvement of the eccrine glands with syringometaplasia has been reported in the past as "syringolymphoid hyperplasia with alopecia," " syringotropic cutaneous T-cell lymphoma," " adnexotropic T-cell lymphoma," or " syringotropic MF." The clinicopathologic features of this variant are not well understood, and only a few case reports or small series have been published to date. We reviewed the clinicopathologic features of 14 patients with syringotropic MF (male: female - 10: 4; median age, 59 years; mean age, 57.8; age range, 33 to 83 y). Six patients had variably large, solitary patches or plaques, located on the thigh (n = 3), arm, trunk, or eyebrow (1 each). The other 8 patients had multiple, mostly generalized lesions. A history of MF was known in 4 of these 8 patients. With the exception of 1 biopsy specimen that was too superficial and did include the eccrine secretory coils but not the eccrine glands, all cases showed prominent involvement of the eccrine glands. Variable degrees of syringometaplasia ranging from small to large epithelial complexes were present in all specimens. The eccrine glands and syringometaplastic structures were surrounded by dense lymphoid infiltrates with prominent epitheliotropism. Concomitant involvement of the epidermis and of the hair follicles was observed in 13 and 8 biopsies, respectively. This is the largest series of syringotropic MF, showing that this is a rare variant of the disease with peculiar clinicopathologic features. Dermatologists and dermatopathologists should be aware of this rare variant of MF to avoid delayed diagnosis and treatment.