Superficial paramucosal clear cell sarcoma of the soft parts resembling melanoma in a 13‐year‐old boy

• Published in: Journal of cutaneous pathology 2013-02, Vol.40 (2), p.265-268
• Main Authors: Sidiropoulos, Michael, Busam, Klaus, Guitart, Joan, Laskin, William B., Wagner, Annette M., Gerami, Pedram
• Format: Article
• Language: English
• Subjects: Adolescent; clear cell sarcoma; Diagnosis, Differential; FISH; Humans; Immunohistochemistry; In Situ Hybridization, Fluorescence; Lip Neoplasms - genetics; Lip Neoplasms - metabolism; Lip Neoplasms - pathology; Male; melanoma; Melanoma - genetics; Melanoma - metabolism; Melanoma - pathology; melanoma of soft parts; Oncogene Proteins, Fusion - genetics; Sarcoma, Clear Cell - genetics; Sarcoma, Clear Cell - metabolism; Sarcoma, Clear Cell - pathology; Skin Neoplasms - genetics; Skin Neoplasms - metabolism; Skin Neoplasms - pathology
• ISSN: 0303-6987; 1600-0560
• DOI: 10.1111/cup.12058

Clear cell sarcoma (CCS) of tendons and aponeuroses, also known as melanoma of soft parts, represents an aggressive rare malignancy that is characterized by a nested or fascicular pattern of spindled cells and a pathognomonic reciprocal translocation, t(12;22)(q13;q12), that results in the fusion of EWSR1 and ATF1 genes. Numerous recent studies have recognized the importance of a cutaneous CCS variant that can mimic a broad spectrum of entities, including spindle cell melanoma, spindle cell squamous carcinoma, cutaneous leiomyosarcoma and atypical fibroxanthoma. We report a case of a 13‐year‐old boy with cutaneous CCS who presented with a few months history of an asymptomatic papule on the lower lip that was suggestive of a mucocele. Biopsy of the lesion showed a wedge shaped neoplasm arranged in nests and fascicles of epithelioid‐ to oval‐shaped cells with pale cytoplasm, open chromatin and prominent nucleolus. The superficial component was closely opposed to the basal epithelium resembling the junctional nests of a melanocytic neoplasm. The process extended into and involved the striated muscle of the lip. The cells expressed S‐100, CD99 and synaptophysin by immunohistochemistry, and there was focal HMB‐45 and microphthalmia transcription factor (MiTF) positivity as well. Fluorescence in situ hybridization confirmed the presence of the t(12;22) (ESWR1‐ATF1) translocation.