Exocoelomic Cyst: Rare Benign Pancreatic Lesion Explained

Exocoelomic cysts (also called benign pancreatic cysts of coelomic origin) are rare, non-neoplastic cystic lesions arising from displaced embryonic coelomic epithelium. They account for 0.5–5.1% of all pancreatic cysts and are most frequently diagnosed in adult men (mean age 50–60).

Clinical Presentation

• Typically asymptomatic—found incidentally on abdominal imaging (CT/MRI) for unrelated reasons.
• When symptomatic: vague epigastric discomfort, dull abdominal pain, or early satiety.
• Rarely cause pancreatitis, jaundice, or obstruction.

Imaging Features

• Well-circumscribed, unilocular, thin-walled cyst.
• No communication with the pancreatic ductal system (key differentiator from IPMN/MCN).
• Fluid attenuation on CT; T2 hyperintensity on MRI.
• No enhancing solid components or septations.

Diagnosis

Definitive diagnosis requires histopathology after resection: lining by flattened to cuboidal epithelium (mesothelial-like), absence of ovarian-type stroma (unlike MCN), and no ductal connection. Preoperative diagnosis is presumptive based on imaging.

Management

• Conservative surveillance with serial imaging (MRI/MRCP) for asymptomatic, typical lesions.
• Surgical resection (distal pancreatectomy or enucleation) if:
  • Symptoms persist or worsen.
  • Size >3–4 cm or growing.
  • Atypical imaging features (thick wall, septations, enhancement).
  • Diagnostic uncertainty.

Malignant transformation is exceedingly rare. Long-term prognosis after resection is excellent. Multidisciplinary discussion (radiology, surgery, pathology) is recommended for indeterminate cases.