Benign schwannoma of the hepatoduodenal ligament

Schwannomas are nerve sheath tumors comprised entirely of Schwann cells, which normally produce the insulating myelin sheath that covers peripheral nerves. They are usually homogeneous tumors, frequently located in the head, neck, spinal cord, and extremities, but rarely in the retroperitoneum, representing only 6 % of all retroperitoneal tumors [1]. In a recently conducted literature review, we found only two published case reports of a schwannoma of the hepatoduodenal ligament, both in female patients over the age of 40 [2] [3] [4].

We report a case of a 29-year-old man who was referred for a surgical consultation for evaluation of a pericholedochal cystic mass of uncertain nature, detected during annual ultrasound surveillance of asymptomatic vesicular polyps. No abnormalities were detected on clinical examination and in laboratory investigations. Fine needle aspiration guided by ultrasound revealed amorphous proteinaceous material with rare histiocytes, mesothelial cells, and spindle cells arranged in bundles and palisades, with no nuclear or cytoplasmic atypia, suggestive of spindle cell neoplasia or stromal tumor. Endoscopic ultrasonography was performed to clarify the nature of the mass, showing a complex cystic lesion in nature, with solid areas, measuring 45 × 29 mm in the sagittal plane, located in the subhepatic region, keeping the planes of cleavage with the liver, portal vein, and hepatic artery ([Fig. 1]). Biopsy of the mass was not possible due to vessel interposition ([Fig. 2]). Abdominal magnetic resonance imaging (MRI) showed a heterogeneous mass adjacent to the gallbladder ([Fig. 3]). The patient underwent laparotomy with removal of a multilocular cystic mass of the hepatoduodenal ligament. Histopathologic examination revealed a finely capsulated spindle cell neoplasm with whirling pattern, typical Verocay bodies, demonstrating intense and universal S100 positivity, diagnostic of a benign schwannoma ([Fig. 4]).

Fig. 1 Heterogeneous mass on endoscopic ultrasound.

Fig. 2 Vessel interposition, making mass biopsy unfeasible.

Fig. 3 a, b Magnetic resonance imaging (MRI; b: coronal plane) showing a heterogenous mass adjacent to the gallbladder.

Fig. 4 Intense and universal nuclear positivity with S100, revealing the typical cytological and architectural aspects of schwannoma.

Endoscopy_UCTN_Code_CCL_1AF_2AG_3AD

References

• 1 Lane R, Stephens D, Reiman H. Primary retroperitoneal neoplasms: CT findings in 90 cases with clinical and pathologic correlation.  AJR Am J Roentgenol. 1989;  152 83-89
• 2 Nagafuchi Y, Mitsuo H, Takeda S et al. Benign schwannoma in the hepatoduodenal ligament: report of a case.  Surg Today. 1993;  23 68-72
• 3 Fenoglio L, Severini S, Cena P et al. Common bile duct schwannoma: A case report and review of literature.  World J Gastroenterol. 2007;  13 1275-1278
• 4 Jung J, Joo K, Chae M et al. Extrahepatic biliary schwannomas: A case report.  J Korean Med Sci. 2007;  22 549-552