Background:
Clear cell sarcoma (CCS), also known as malignant melanoma of soft parts, is a rare type of soft tissue sarcoma which exhibits morphological, immunohistochemical and ultrastructural similarity with malignant melanoma. It is rarely localized in the intestine and the natural history of this tumor is not yet clear.
Case report:
A 49-year-old woman presented with diffuse abdominal colicky pain and vomitus over the previous seven days. An X-ray of the abdomen revealed obstruction of the small intestine. The patient underwent contrast enhanced abdominal computerized tomography (CT), which confirmed the obstruction at the jejunum and an associated circumferential wall thickening extending about 3 cm in length, causing concentric narrowing of the lumen. At laparotomy, a mass was recognized at the level of the jejunum in the small intestine, which caused almost complete obstruction of the lumen. At the point of obstruction, adhered loops of small intestine were found. A segmental small bowel resection was performed with 5 cm clear margins and its respective mesenteric lymph nodes.
Results:
Histological examination of the specimen revealed a tumor (3×3×2 cm) with epithelioid cell characteristics and eosinophilic or clear cytoplasm and focal translucent nuclei. Immunohistochemistry was positive for S100, epithelial membrane antigen (EMA) and synaptophysin. The tumor was pankeratin AE1/AE2, GFAP, HMB45 and MART-1/Melan-A negative. Twelve lymph nodes were retrieved and were free of neoplastic infiltration. Cytogenetic examination revealed translocation of the EWSR1 gene. The patient had an uncomplicated postoperative course and left the hospital seven days after her admission in good general condition. After 20 months of follow-up the patient remains asymptomatic without any clinical or radiological evidence of recurrence.
Conclusion:
CCS sarcoma can be rarely localized in the jejunum. Due to its morphological similarity to malignant melanoma, cytogenetic examination is necessary for its diagnosis. Wide resection of the tumor and its respective lymph nodes was associated with a 20-month disease free survival in this patient.