A Case of Peritoneal Mesothelioma in the Inguinal Region Diagnosed in a Patient with Fever of Unknown Origin

Abstract

A 78-year-old woman was diagnosed with fever of unknown origin and referred to our hospital by a local doctor. She presented with continuous high fever, a high white blood cell (WBC) count, and a high C-reactive protein (CRP) level, and a 5-cm mass was found in the left lower abdomen extending to the inguinal region. Since the cause of the fever could not be identified, resection of the left inguinal mass was performed to confirm the diagnosis. A tumor measuring 6 cm in diameter was embedded in the pubic bone, inguinal canal, posterior wall of the inguinal region, and external oblique aponeurosis. Tumor resection and inguinal lymph node dissection were performed. Pathological examination showed peritoneal mesothelioma originating from the left inguinal region with regional lymph node metastasis. After surgery, WBC and CRP levels normalized quickly, and the fever resolved. In addition, anemia improved, and the preoperatively elevated sIL2-R and serum IL-6 levels normalized. No recurrence has been observed for over one year after surgery without adjuvant chemotherapy.

Peritoneal mesothelioma accounts for 10-20 % of all mesotheliomas and is difficult to diagnose due to non-specific symptoms. An extremely rare case of an inguinal peritoneal mesothelioma presenting as fever of unknown origin is reported.