Dermatomyositis and peritoneal papillary serous carcinoma

We describe an unusual case of peritoneal papillary serous carcinoma (PPSC) arising in a female patient with dermatomyositis (DM). Despite periodic extensive searches for an underlying malignancy, no malignancy had been detected in this patient during the first 2.5 years after the diagnosis of DM. It was only when the patient presented with pleural effusion and ascites that the underlying intra-abdominal malignancy was detected by laparoscopy. Treatment with four cycles of pre-operative chemotherapy (taxol and cisplatin) resulted in tumor regression with amelioration in the muscular manifestation of the DM, but without parallelic amelioration in the skin manifestations of the DM. Explorative laparotomy confirmed the presence of papillary serous carcinoma in the omentum, surface of the left ovary and the retroperitoneal lymph nodes, and established the diagnosis of PPSC. Following two cycles of postoperative chemotherapy, the patient is alive with no evidence of internal malignancy. However, although muscle strength and enzymes have remained normal, no effect on the skin manifestation of DM has been observed. This case illustrates that, alongside the more frequently occurring ovarian carcinoma, PPSC should also be considered in the differential diagnosis of the underlying malignancy that may occur in the female patient with DM.