A huge intra‐abdominal mass in a young man

Clinical presentation

A 19‐year‐old man presented to our department because of a 3‐year history of left upper abdominal distention. He had no notable past medical history such as abdominal trauma or pancreatitis. On physical examination, a huge elastic hard mass was palpable in the left abdomen, but he did not complain of tenderness. Laboratory data on admission were unremarkable, including normal values for white blood cell count, C‐reactive protein, pancreatic enzymes (pancreatic amylase and lipase) and tumour markers (CEA and CA19‐9). IV contrast‐enhanced abdominal computed tomography showed a cystic lesion 21 cm in diameter located mainly in the left upper abdomen (fig 1, 2). A well‐enhanced crescent‐shaped structure was also noted adjacent to the cyst (fig 1). Endoscopic retrograde pancreatography revealed no abnormal findings apart from leakage of contrast medium into a cystic lesion at the tail of the pancreas (fig 3).

Figure 1 Computed tomography scan on admission (axial image).

Figure 2 Computed tomography scan on admission (coronal reformatted image). S, spleen.

Figure 3 Endoscopic retrograde pancreatography reveals extravasation of the contrast medium into the cystic lesion at the tail of the pancreas.

Question

What is the diagnosis of the cystic lesion?

See page 1393 for answer