[A Case of Castleman's Disease with Lymphadenopathy during the Treatment of Gastric Cancer].

We report a patient who had Castleman's disease with lymphadenopathy during the treatment of gastric cancer. In May 2017, a 63-year-old man underwent gastrointestinal endoscopy, which revealed a tumor on the posterior wall of the lower part of the stomach. Based on a biopsy, he was diagnosed with suspected adenocarcinoma, Group 4. In June 2017, he visited our hospital, and endoscopic submucosal dissection(ESD)was performed. The pathological diagnosis of the resected specimens was L, Less, 20×10 mm, Type 0-Ⅱc, tub1, pT1a(M), UL(-), ly(-), v(-), pHM0, pVM0, pStage ⅠA. He was referred to our department for the treatment of abdominal lymphadenopathy. His lymphadenopathy was localized in the gastric lesser curvature as an enlarged lymph node 15mm in size, based on the findings of contrast-enhanced CT. On FDG- PET/CT, we found a slight accumulation of SUVmax 2.4 in the early phase in the same lymph node. We could not confirm a diagnosis, and we performed laparoscopic dissection of the lymph node for diagnosis and treatment. The size of the specimen was 14×14mm, surface was smooth, and lymph node was elastic and soft. We found lymphoid follicles with atrophic germinal center using HE staining. We also found increased hyperplastic blood vessels around the germinal center, and he was diagnosed with hypervascular Castleman's disease.