title: Primary cutaneous alveolar rhabdomyosarcoma of the perineum.
abstract: Primary alveolar rhabdomyosarcoma (RMS) involving perineal skin is extremely rare, particularly in the infant age group. We report a case of an alveolar RMS in a newborn with abnormal symmetrical perineal overgrowth, causing ambiguous morphologic structure of the genitalia. Clinical and imaging studies were suggestive of Proteus syndrome with lymphatic malformation. Histologic examination of the mass showed cutaneous alveolar RMS with areas of embryonal and pleomorphic RMS features. Multiple superficially located, cystic-dilated spaces with loose edematous-mucoid hypocellular stroma gave a gross morphologic structure similar to that of lymphatic-type excrescences.
authors.affiliation: Department of Pathology, Children's Memorial Hospital, Northwestern University Medical Center, Chicago, Ill 60614, USA.
authors.forename: Yun
authors.initials: Y
authors.lastname: Gong
authors.forename: Jerome
authors.initials: J
authors.lastname: Chao
authors.forename: Bruce
authors.initials: B
authors.lastname: Bauer
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Sun
authors.forename: Pauline M
authors.initials: PM
authors.lastname: Chou
mesh_terms: D005260:Female; D006801:Humans; D007223:Infant; D010502:Perineum; D018232:Rhabdomyosarcoma, Alveolar / Q000473:pathology*; D012878:Skin Neoplasms / Q000473:pathology*