A 65-year-old woman was referred for the treatment of an ill-defined neoplasm of the glabella (Figure 1) diagnosed based on a 3-mm punch biopsy at an outside institution as a "basaloid neoplasm with sweat duct differentiation." An excisional biopsy was performed due to uncertainty of diagnosis, and histopathology revealed poorly circumscribed basaloid cells in a fibrous stroma with an infiltrating growth pattern extending to peripheral margins. The case was sent out for expert consultation, and a diagnosis of microcystic adnexal carcinoma (MAC) was rendered. Mohs micrographic surgery (MMS) was pursued for definitive treatment. The patient underwent 4 stages of MMS with a 3-cm defect (Figure 1B). In each stage, a proliferation of syringomatous elements occurring in association with dilated and inspissated eccrine ducts with occasional microcysts was seen, and dermal fibrosis was noted (Figure 2). The majority of the lesion appeared confined to the dermis in a discontinuous fashion, and no perineural invasion was noted. After the fourth stage, residual tumor was still present. However, given that the tumor was confined to the dermis, it was multifocal in nature, and it lacked perineural invasion; we suspected that this lesion may be a plaque-type syringoma (PTS). Surgery was halted, and the tissue was sent for a second expert consultation to another institution, and a diagnosis of a PTS was made, confirming the surgeon's suspicion that this was not an MAC, but rather a benign multifocal lesion. The patient's glabellar defect was repaired with a forehead flap.
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