Epidermoid Cyst in an Intrapancreatic Accessory Spleen Complicating Clinical Decision-Making: A Case Report With Characteristic Imaging Findings.

Epidermoid cyst in intrapancreatic accessory spleen (ECIPAS) is a rare benign condition that occasionally mimic malignant pancreatic neoplasms. We present a case of ECIPAS in a 53-year-old asymptomatic male, initially discovered incidentally during imaging for a suspected hepatic hemangioma. The lesion, located in the pancreatic tail, demonstrated characteristic imaging features on contrast-enhanced computed tomography and superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance imaging (MRI), including a cystic component with peripheral solid tissue exhibiting splenic enhancement patterns. Despite these typical ECIPAS findings, the lesion increased in size from 38 × 33 mm to 50 × 45 mm over 12 months, accompanied by a significant rise in serum carbohydrate antigen 19-9 (CA19-9) from 21 to 330 U/mL. This clinical progression raised concerns about potential malignancy, leading to a robot-assisted spleen-preserving distal pancreatectomy. Histopathological examination confirmed the diagnosis of ECIPAS. Postoperatively, the patient's serum CA19-9 levels normalized. This case highlights that ECIPAS can complicate clinical decision-making through size increase and CA19-9 elevation, complicating preoperative diagnosis. However, careful analysis of imaging characteristics, particularly on SPIO-enhanced MRI, can aid in accurate diagnosis.
Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. The Research Ethics Committee of the University of Tokyo issued approval 2561-(23). Written informed consent was waived due to the retrospective noninvasive nature of the study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.
(Copyright © 2024, Tsujimoto et al.)