Pancreatic schwannoma mimicking pancreatic cystadenoma: A case report and literature review of the imaging features

Abstract

Introduction: Schwannomas, also known as neurilemmoma, are benign neoplasms that originating from Schwann cells in peripheral nerve sheaths. The head, neck, and extremities are the most common sites; however, pancreatic schwannomas are rare neoplasms. Accurate preoperative diagnosis of these tumors is very tough because of pancreatic schwannomas usually mimicking other cystic tumors. Here we present a case of pancreatic schwannoma misdiagnosed as pancreatic cystadenoma.

Patient concerns: We presented a rare case of a 55-year-old female admitted to our hospital for abdominal distension. The physical examination and results of laboratory testing reveal no abnormalities.

Diagnosis: A computed tomography (CT) scan detected a hypodense 2.4 cm × 2.6 cm mass with a clear margin at the neck of the pancreas. Pancreatic cystadenoma was strongly suspected.

Interventions: The patient underwent robotic distal pancreatectomy with splenectomy. The gross specimen showed a pale and solid mass with a capsule.

Outcomes: Histological examination of the surgical specimen demonstrated a pancreatic schwannoma. Immunohistochemistry results were as follows: S-100 (+), CD117 (-), SMA (-), and Desmin (-). She was discharged on postoperative day 6 and no recurrence of the tumor happened during the 12-month follow-up.

Conclusion: Precise preoperative diagnosis of pancreatic schwannomas is very difficult despite the application of multiple imaging modalities. Surgery is the most effective treatment for this rare disease and the final diagnosis usually relies on pathology. Following complete tumor removal, patients with pancreatic schwannomas generally have a good prognosis.

Figure 1

The 3.1 × 2.0 cm hypoechoic lesion with morphological rules and border clear at pancreatic body (A) without clear blood flow inside the signal (B).

Figure 2

There was a 2.4 cm × 2.6 cm lesion with low density located at the neck of the pancreas on enhanced scan (A). Pancreatic duct showed no obvious expansion. Venous phase also manifested no obvious abnormalities (B).

Figure 3

Photomicrograph showed spindle cells arranged in fascicular or whorled patterns. There was hypercellular and characterized by closely packed spindle cells with occasional nuclear palisading (A 100×). S-100 stain was positive (B 100×). The section of the tumor was pale and solid, and the tissue had clear boundary with capsule (C, D).