A Case of Inflammatory Pseudotumor of the Mesentery that was Difficult to Differentiate from Solitary Lymph Node Recurrence after Laparoscopic Anterior Resection for Rectal Cancer

Abstract

The patient was a 52-year-old woman who had undergone low anterior resection with D3 lymph node dissection for advanced rectal cancer. The final histopathological diagnosis was advanced lower rectal cancer, pT4a N0 M0, pStage II. An abdominal ultrasound examination performed 10 months after the surgery revealed a tumor measuring 33 mm in diameter in front of the left common iliac artery. FDG-PET showed increased uptake in the tumor. Solitary lymph node metastasis from the rectal cancer was suspected. Because abdominal CT and PET-CT showed no evidence of any other metastases, a laparotomy was performed. The nodule was located at the root of the superior rectal artery that had been resected at the initial surgery ; therefore, it was considered as recurrence in #252 lymph node. Histopathological examination of the resected specimen, which included two laparoscopic clips, however, revealed inflammatory changes and elastic fibers with no malignant cells. Thus, the tumor was diagnosed as an inflammatory pseudotumor. The patient has been followed-up for one and a half years, and has shown no evidence of recurrence.