title: Pilomatrix carcinoma: a case report and review of the literature.
abstract: Pilomatrixoma is a common benign neoplasm of children and young adults with a female predilection. In contrast, its malignant counterpart, pilomatrix carcinoma is a rare neoplasm of older adults with a male preponderance. Pilomatrix carcinomas are locally aggressive with a tendency to recur. We report a case of a 44-year-old male who presented with an enlarging soft tissue tumor on the right upper back. Histology revealed an asymmetric, poorly circumscribed, lobulated neoplasm located deeply in the dermis with infiltration into the underlying subcutaneous tissue. The tumor was comprised of basaloid cells containing vesicular nuclei, prominent nucleoli, scant cytoplasm, and brisk mitotic activity. A focus of basaloid cells transitioning to shadow cells with central keratinized material and tumor necrosis was also present. The diagnosis of a pilomatrix carcinoma was rendered. Considering the infiltrative nature of this neoplasm with perineural and intramuscular invasion, the patient underwent 3 surgical excisions before it was completely removed.
authors.affiliation: Department of Pathology, University of Massachusetts Medical School, Worcester, MA, USA. kristine.cornejo@umassmemorial.org
authors.forename: Kristine M
authors.initials: KM
authors.lastname: Cornejo
authors.forename: April
authors.initials: A
authors.lastname: Deng
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002277:Carcinoma / Q000473:pathology* / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D005260:Female; D006201:Hair Diseases / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D009361:Neoplasm Invasiveness; D011237:Predictive Value of Tests; D012086:Reoperation; D012867:Skin / Q000473:pathology*; D012878:Skin Neoplasms / Q000473:pathology* / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult