Intraabdominal Desmoplastic Small Round Cell Tumour of the Peritoneum

Overview

The authors described three cases of intraabdominal desmoplastic small round cell tumour of theperitoneum (IDSRT). In one case the patient was a woman, and in the other two men. The ageranged from 20–29 years. Common of all the cases was a rapid onset of clinical symptoms duringthe period of twelve to eighteen months. In one case, a 22-year-old woman presented with a symptomlesscourse of disease documented by medical examination one month ago. Intensive chemotherapywas applied but two patients died of generalisation. The 22-year-old woman is alive butwith clinical evidence of generalisation in the abdominal cavity. The „classical“ type of IDSRTwas found in all the cases. Sharply demarcated groups of tumour cells of different size weresurrounded by dense fibrous stroma. In some regions desmoplastic areas prevailed. In one casethe tumour consisted of round and oval cells resembling a lymphoma. In the other two cases, theslightly elongated cells were present. Immunohistologically, the small round cells were positivefor cytokeratins with antibody AE1-AE3. Membrane and dot-like paranuclear positivity werefound. In 2 cases the reaction to desmin was seen in a dot-like paranuclear distribution, whereasthe reaction to smooth muscle actin (MSA) was negative. In all the cases positivity to vimentinand neuron specific enolase (NSE) were apparent. Negative reactions were found for WT-1 antibodyin all three cases. In one of the cases the RT PCR reaction for chimeric gene EWS/WT1 wasperformed, and found to be negative. Many different tumour types, such as lymphoma, Ewingsarcoma/PNET, neuroblastoma, alveolar rhabdomyosarcoma, malignant mesothelioma must beexcluded. Cytogenetic examination should be performed on tumours with a „non-typical“ histologicalpattern and uncommon inmmunohistological examinations.

Key words:
intraabdominal desmoplastic small round cell tumour of the peritoneum –⁠ immunohistologicalfindings –⁠ electron microscopic findings