SMARCB1 (INI1)-deficient Rhabdoid Pancreatic Carcinoma: A Rare Subtype of Pancreatic Cancer

OpenAlex · English

Rhabdoid pancreatic carcinoma (RPC) is a rare and highly aggressive subtype of undifferentiated pancreatic carcinoma characterized by rhabdoid morphology and frequent loss of SWItch/sucrose non-fermentable chromatin-remodeling complex-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1 (SMARCB1), integrase interactor 1 (INI1) expression.Due to its rarity, its clinicopathological characteristics and optimal management remain poorly defined.A 56-year-old woman with an Eastern Cooperative Oncology Group performance status of 1 presented with a one-month history of abdominal and back pain.Contrast-enhanced computed tomography revealed an infiltrative pancreatic head mass measuring 125×52×75 mm, with vascular involvement and multiple metastatic lymph nodes.Histopathological examination demonstrated RPC, with complete loss of nuclear SMARCB1 (INI1) expression by immunohistochemistry. Comprehensive next-generation sequencing showed KRAS wild-type status.The patient received modified 5-fluorouracil, leucovorin, irinotecan, and oxaliplatin (mFOLFIRINOX) chemotherapy and achieved partial regression of metastatic abdominal lymph nodes after six cycles.Treatment was continued for a total of 12 cycles before disease progression was documented.This case highlights the aggressive clinical behavior and distinctive molecular profile of SMARCB1 (INI1)-deficient RPC.The observed partial response to mFOLFIRINOX suggests that selected patients may derive temporary benefit from systemic chemotherapy; however, durable disease control remains challenging.Increased recognition of this rare entity and further investigation of molecularly targeted and immunotherapeutic strategies are needed to improve outcomes.