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Soft Tissue Sarcomas Interactive CourseAuthor: André Mascarenhas Oliveira - Pathology ResidentMayo Clinic, Rochester, MN - USA |
16-year old adolescent male presents with diffuse abdominal pain and distension. Laparotomy evaluation discloses a large gray mass attached to the peritoneum. The mass measures 19 cm and is surrounded by multiple nodules, also attached to the peritoneum, ranging in diameter from 1 to 4.5 cm. Microscopic examination of the large mass shows clusters of small round blue cells with an increased mitotic activity surrounded by a prominent desmoplastic stroma (pictures 1 and 2).
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Figure 1. (click here to zoom) Figure 1. |
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Figure 2. (click here to zoom) Figure 2. |
Desmoplastic small round cell tumor (DSRCT) is a highly malignant neoplasm that was first described in 1989 by Gerald and Rosai1. It usually affects young persons during the second decade of life with a striking male predilection (male to female ratio: >5:1). The tumor occurs most commonly in the peritoneal cavity, causing abdominal pain, distension, and occasionally ascites. A predominant mass, which can reach more than 30 cm in greatest dimension, associated with multiple satellite nodules, is frequently disclosed during the laparotomy. The mass is generally firm and white-gray.
Microscopically, clusters of small round blue cells surrounded by a prominent desmoplastic stroma are characteristic. Immunohistochemical studies reveal a peculiar feature: DSRCT coexpresses epithelial and mesenchymal markers. Cytokeratin, desmin (with a characteristic dot-like quality) and neuron-specific enolase positivity point toward a malignant transformation of a primitive cell. Cytogenetic analysis demonstrates the translocation t(11;22) in almost all cases with the involvement of the Wilm's tumor suppressor gene (11p13) and the Ewing's sarcoma gene (22q12). The treatment includes surgical excision and chemotherapy and, in spite of an aggressive treatment, the prognosis is usually very poor2,3.
1. Gerald WL, Rosai J. Desmoplastic small cell tumor with divergent differentiation. Ped Pathol 9:177-183, 1989.
2. Gerald WL, Miller HK, et al. Intra-abdominal desmoplastic small round cell tumor: report of 19 cases of a distinctive type of high-grade polyphenotypic malignancy affecting young adults. Am J Surg Pathol 15(6): 499-513, 1991.
3. Leuschner I, Radig K, Harms D. Desmoplastic small round cell tumor. Sem Diag Pathol 13(3): 204-212, 1996.
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