Eccrine syringofibroadenoma (Mascaró). An acrosyringeal hamartoma.

Two patients with eccrine syringofibroadenomas were studied. The first patient had a 3-year history of asymptomatic, unilateral, linear, moist mosaic plaques of the lower part of the left leg and foot; the second patient had a solitary papule on the back. Histologically, both tumors exhibited superficial elongated strands of eccrine ductal epithelium containing occasional lumina lined by an eosinophilic cuticle. The stroma was loose, myxoid, and fibrovascular. The secretory portions of the eccrine glands were ectatic in the first patient but were not seen in the second patient. We believe these lesions represent acrosyringeal hamartomas (nevi), although some authors interpret them as adenomas. The literature seems to indicate that lesions with similar histologic features may be solitary, multiple, or combined with other neoplasms; in other cases, the lesions may possibly represent an unusual morphologic expression of hidrotic ectodermal dysplasia.