RHABDOID PANKREATIC CARCINOMA: A RARE SUBTYPE OF PANKREATIC CANCER

Yılmaz M., Büyükkıroğlu M., Demir M.

15. INTERNATIONAL GASTROINTESTİNAL CANCERS CONFERENCE , Antalya, Turkey, 4 - 07 December 2025, pp.23, (Summary Text)

  • Publication Type: Conference Paper / Summary Text
  • City: Antalya
  • Country: Turkey
  • Page Numbers: pp.23
  • Eskisehir Osmangazi University Affiliated: Yes

Abstract

Introduction: Rhabdoid pancreatic carcinoma (RPC) is a rare form of undifferentiated pancreatic carcinomas (PC) and characterized by loss of SMARCAB1/INI1 and the designation “rhabdoid” in PC reflects its histopathologic resemblance to rhabdomyosarcoma. The main subtypes are pleomorphic and monomorphic anaplastic RPC. Herein, we present a case of metastatic RPC. Case Presentation: A 56-year-old female presented with abdominal and back pain in the last month. Contrast-enhanced upper abdomen-pelvic computed tomography (CT) revealed a 38×29 mm mass lesion located in the gallbladder fundus and a 125×52×75 mm mass surrounding the common bile duct at the pancreatic head, demonstrating invasion to paraaortic paracaval regions. The findings were highly suggestive of a pancreatic head malignancy, in contact with the celiac trunk, superior mesenteric artery, and portal vein, along with multiple metastatic conglomerate lymphadenopathies. Tumor markers were within the normal range and the abnormal laboratory findings were as follows: Aspartate aminotransferase: 78 U/L, alanine aminotransferase: 170 U/L, alkaline phosphatase: 239 U/L, gamma glutamyl transferase: 215 U/L. Thoracic CT revealed multiple pathological lymph nodes within the mediastinum, the largest measuring 2.5 cm in the left upper paratracheal region. Histopathological of the pancreatic head mass revealed findings consistent with PC. The treatment was continued for up to 12 cycles, as partial regression of the pathological lymph nodes in the abdomen was observed after 6 cycles of fluorouracil (5-FU) 2400 mg/m² infusion and 400 mg/m² intravenous bolus, irinotecan 180 mg/m², oxaliplatin 85 mg/m², and leucovorin 400 mg/m² administered every 14 days (mFOLFIRINOX). At the end of treatment, progression in several lymph nodes was observed while the pancreatic lesion remained stable. The comprehensive next generation sequencing of the tumor tissue revealed no KRAS mutation. The patient was started on a chemotherapy regimen consisting of gemcitabine (900 mg/m² on days 1 and 8) plus docetaxel (100 mg/ m² on day 8), administered every 21 days. Discussion: RPC is a very rare form and has a worse prognosis, particularly in unresectable tumors. The principal immunohistochemical hallmark of RPC is the loss of SMARCB1/INI1 expression, a core subunit of the SWI/SNF chromatin-remodeling complex that functions as a tumor suppressor. The rapid disease progression on mFOLFIRINOX observed within the first six months in our case suggests an aggressive clinical course.  Conclusion: The loss of SMARCB1/INI1 expression is the defining mark of RPC. The responses to mFOLFIRINOX are unsatisfactory. Therefore, target gene mutations as KRAS mutations need to be investigated in all patients. Given its highly aggressive nature and poor prognosis, RPC underscores the urgent need for innovative and personalized therapeutic approaches.