A rare case of eosinophilic gastritis induced by nivolumab therapy for metastatic melanoma.

Cancer immunotherapy using immune checkpoint inhibitors can cause immune reactions at various sites as a side effect called immune-related adverse events (irAEs). The gastrointestinal tract is susceptible to irAEs, however, the degree and presentation vary considerably from case to case. A 76-year-old woman was diagnosed with anal mucosal melanoma. She underwent radical surgery and received postoperative adjuvant therapy. However, because new metastases were also found in bilateral inguinal lymph nodes, immunotherapy with nivolumab was performed. Approximately 10 months after the initiation of nivolumab administration, she presented with epigastric discomfort and nausea, and her laboratory data showed severe eosinophilia (1938/mm3). Computed tomography demonstrated a diffuse thickening of the gastric wall. Esophagogastroduodenoscopy and endoscopic ultrasonography showed mucosal thickening due to edema, and histologic examination revealed severe invasion of eosinophils in the lamina propria. Subsequently, she was diagnosed with eosinophilic gastritis due to irAEs induced by nivolumab. Oral administration of prednisolone rapidly normalized her endoscopic and histologic findings, dramatically reducing her symptoms. This is a very rare and important case report of nivolumab-induced severe eosinophilic gastritis. Although gastric lesions as IrAEs is rare, it is necessary to differentiate eosinophilic gastritis if unexplained nausea occurred during the administration of immune checkpoint inhibitors.

A case of idiopathic portal hypertension accompanying multiple hepatic nodular regenerative hyperplasia in a patient with systemic sclerosis.

Idiopathic portal hypertension (IPH) is one of the background diseases causing nodular regenerative hyperplasia (NRH). Furthermore, IPH patients accompanied with autoimmune diseases, such as systemic lupus erythematosus (SLE) and systemic sclerosis (SSc), are more likely to form NRH in the liver. A 76-year-old woman had been aware of the Raynaud's phenomenon and scleroderma for the past 30 years. In this case, she presented with abdominal fullness, and her imaging analysis revealed ascites and multiple liver nodules. On Gd-EOB-DTPA enhanced magnetic resonance imaging (EOB-MRI), donut-like uptake was observed in the nodules in the hepatobiliary phase. Liver biopsy of a nodule demonstrated that it was composed of hyperplastic hepatocytes without fibrous septa, and dilated sinusoids were observed beside the nodule. Conversely, background liver showed that peripheral portal veins appeared stenotic with dense fibrosis in the portal area. The final diagnosis was that multiple NRH of the liver developed in SSc patient accompanying IPH. This case suggests that NRH may be unexpectedly diagnosed in patients with autoimmune diseases accompanying IPH.