Epstein-Barr Virus associated gastric carcinoma in a patient with germline STAT3 gain-of-function mutation

Abstract Introduction/Objective Signal transducer and activator of transcription 3 (STAT3) is a transcription factor involved in inflammation, proliferation, differentiation and survival. STAT3 gain-of-function (GoF) disorders are characterized by immune dysregulation and present with polyendocrinopathy, enteropathy, X-linked syndrome (IPEX)- or autoimmune lymphoproliferative syndrome (ALPS)-like features. While patients with STAT-3 GoF are known to have an increased risk for hematologic malignancies, neither solid tumors nor an increased risk for EBV-associated disorders have been described. We report the first case of an EBV-associated solid organ tumor in a patient with STAT-3 GoF. Methods/Case Report A 21-year-old male with germline mutation in STAT3 (variant p. M329K) presented with early satiety, abdominal pain and worsening of chronic anemia. Serology showed high EBV DNA PCR levels. Endoscopy showed multiple nodular lesions in the stomach, which were biopsied to reveal EBV-associated high-grade dysplasia and intramucosal adenocarcinoma. Initiation of chemotherapy with a poor response led to a total gastrectomy. Gross examination of the specimen showed a 7.9 x 6.5 x 1.8 cm tan-brown, exophytic mass in the posterior wall of the body and antrum, involving the greater curvature. Histology revealed an adenocarcinoma with tubulovillous morphology extending into the lamina propria, without invasion into the muscularis mucosa or submucosa. EBER in-situ hybridization was diffusely positive in the tumor cells. The background mucosa showed severe chronic active and atrophic gastritis with intestinal metaplasia and low-grade dysplasia. All the seventy examined lymph nodes were negative for metastasis. Helicobacter-like organisms were not seen. Results (if a Case Study enter NA) NA Conclusion This is the first report of a solid tumor in a patient with STAT3 GoF mutation. The role of the patient’s underlying immune dysregulation disorder in the development of EBV-associated gastric adenocarcinoma is unclear and warrants further investigation. The case also highlights the importance of a close clinical follow-up in this patient population, as unexpected malignancies can develop at younger ages.