Pitfalls in diagnosing a small cystic insulinoma: a case report

Abstract

Insulinoma is a rare pancreatic endocrine tumour and is typically sporadic and solitary. Over 90% of all insulinomas are benign. Cystic insulinomas are also rare. It is not difficult to determine the site of such neoplasm, as cystic insulinomas are usually 4-10 cm in diameter. We present the case of a patient with a histologically confirmed cystic insulinoma diagnosed after approximately 10 years of hypoglycaemia symptoms. This case is unique because of the small size (2.2 cm) of the tumour. Endoscopic ultrasound (EUS) was useful for localizing this tumour.

Figure 1

Endoscopic ultrasonography showing a cystic tumour in the pancreatic body (Olympus GIF-130 video echo-endoscope with 7.5/12 MHz switchable radial probe).

Figure 2

Postoperative finding: 2.5 × 2 × 2 cm well bounded tumour, weighing 4 grams, cystic formation of 8 mm in diameter in the middle of the tumour.

Figure 3

Insulinoma. Acini of exocrine pancreas (in the upper left corner), Haematoxylin-eosin, 60× (A). Insulinoma. Chromogranin A, 200× (Mild to moderate immunopositivity generally and scattered cells with intense immunopositivity. Strongly immunopositive cells of islet of Langerhans in the surrounding tissues) (B).