Incidental Clear Cell Syringoma of the Scalp in a Patient With Lichen Planopilaris.

Syringomas are benign neoplasms of eccrine ducts; glycogen accumulation in the tumor cell cytoplasm results in a clear cell variant of syringoma. Syringoma and syringomatous proliferations (secondary to alteration of the eccrine sweat ducts) have been observed, albeit uncommonly, as an incidental finding in areas of alopecia on the scalp. A 71-year-old woman with scalp hair loss caused by lichen planopilaris had subclinical clear cell syringoma discovered as an incidental observation on evaluation of the biopsy specimen from an area of hair loss. Including our patient, scalp alopecia-associated syringoma or syringomatous proliferation has been described in a 47-year-old man and 16 women. The women ranged in age from 33 years to 83 years (median, 57 years). The duration of alopecia ranged from six months to 22 years; almost half of the patients (three of seven) had hair loss for 20 or more years. The frontal scalp was the most common location of alopecia; the parietal scalp and the entire scalp with diffuse hair loss were also frequent sites. Prior to biopsy, female pattern alopecia was the most common clinical diagnosis; lichen planopilaris and scarring alopecia were also frequent diagnoses. After the biopsy, pseudopelade was the most common diagnosis; lichen planopilaris and female pattern alopecia were also frequently observed. The pathogenesis of incidental syringomas and syringomatous proliferation in areas of scalp hair loss is postulated to be secondary to subclinical alopecia-related reactive changes.