Emergency Cholecystectomy for Gangrenous Acute Cholecystitis with Profound Thrombocytopenia: Immune Thrombocytopenia Diagnosed Postoperatively.

INTRODUCTION: The optimal source-control strategy for gangrenous acute cholecystitis in patients with profound thrombocytopenia remains unclear. Moreover, infection-associated and immune thrombocytopenia may be difficult to distinguish during the acute phase. CASE PRESENTATION: A 76-year-old man with hypertension, diabetes mellitus, and a history of open distal gastrectomy for gastric cancer presented with gangrenous acute cholecystitis and profound thrombocytopenia (2000/μL). Infection-associated consumptive thrombocytopenia was initially considered, and emergency open cholecystectomy was performed following platelet transfusion. Thrombocytopenia persisted despite source control, and the response to platelet transfusion was suboptimal. The overall clinical course, exclusion of alternative causes, and preserved trilineage hematopoiesis on bone marrow examination supported a clinical diagnosis of immune thrombocytopenia. Treatment with dexamethasone, Helicobacter pylori eradication therapy, prednisolone, and rituximab resulted in platelet recovery. The patient was discharged on POD 16. CONCLUSIONS: This case highlights the necessity of balancing urgent source control against substantial bleeding risk in gangrenous acute cholecystitis with profound thrombocytopenia. Persistent thrombocytopenia following surgical source control, particularly with a suboptimal response to platelet transfusion, should prompt reassessment of the underlying etiology, including immune thrombocytopenia.