Benign schwannoma in the porta hepatis

Neurilemmoma Mimicking a Multilocular Cystic Lesion of the Liver

Neurilemmomas are benign tumors arising from the sheaths of peripheral nerves. They appear rarely in the abdominal cavity. We herein report an 80-year-old man with a multilocular cystic neurilemmoma mimicking a liver lesion. Preoperative images showed a lesion in the porta hepatis. Although a preoperative diagnosis was difficult, surgery was undertaken because of the possibility of malignancy. Histologically, the tumor consisted of spindle-shaped cells with positivity for S-100 protein. The final diagnosis was a neurilemmoma. Porta hepatic neurilemmomas are rare. When we encounter a multilocular cystic lesion of the liver, neurilemmoma should be considered in the differential diagnosis.

Porta hepatic schwannoma: case report and a 30-year review of the literature yielding 15 cases

Background

Schwannomas located in the periportal region are extremely rare. Only 14 cases have been reported in the medical literature worldwide. Cases of porta hepatic schwannomas reported in the literature worldwide were reviewed. As a result, it is very challenging for surgeons to make a preoperative diagnosis due to its rarity and nonspecific imaging manifestations.

Case Presentation

A 57-year-old Chinese female was admitted to our institution with complaint of upper abdominal distension and the abdominal CT in the local hospital revealed a hypodense mass in the porta hepatis. A fine needle aspiration (FNA) was made to confirm the diagnosis, but the result was just suggestive of spindle cell neoplasia. Eventually, the patient underwent surgery and postoperative pathology confirmed schwannoma in porta hepatis. The patient recovered uneventfully with no evidence of recurrence after a follow-up period of 41 months.

Conclusions

It is essential for the final diagnosis of porta hepatic schwannomas to combine histological examination with immunohistochemistry after surgery. The main treatment of porta hepatic schwannomas is complete excision with free margins and no lymph node dissection. In some cases, biliary reconstruction or the proper hepatic and the gastroduodenal artery resection was performed because the tumor was inseparably attached to the extrahepatic bile duct or the proper hepatic and the gastroduodenal artery. Malignant transformation of schwannomas is very rare and the overall prognosis is satisfactory.

Imaging of the porta hepatis: spectrum of disease

A wide array of pathologic conditions can arise within the porta hepatis, which encompasses the portal triad (the main portal vein, common hepatic artery, and common bile ducts), lymphatics, nerves, and connective tissue. Major vascular diseases of the portal triad include thrombosis, stenosis, and aneurysm. Portal vein thrombosis can complicate liver cirrhosis and hepatocellular carcinoma and has important therapeutic implications. Hepatic artery thrombosis and stenosis require immediate attention to reduce graft loss in liver transplant recipients. Congenital (eg, choledochal cyst) and acquired (benign and malignant) diseases of the biliary system can manifest as mass lesions in the porta hepatis. Lymphadenopathy can arise from neoplastic and nonneoplastic entities. Uncommon causes of mass lesions arise from nerves (eg, neurofibroma, neurofibrosarcoma) and connective tissue (sarcomas) and are rare. The hepatoduodenal ligament is a peritoneal reflection at the porta hepatis and is an important route for the spread of pancreatic and gastrointestinal cancers. Imaging plays a major role in diagnosis and enables appropriate management. Ultrasonography accurately demonstrates anatomic variations and pathologic conditions and is the initial modality of choice for detection of vascular and biliary lesions. Multidetector computed tomography and magnetic resonance imaging allow characterization and differentiation of various masses in the porta hepatis. Imaging-guided interventions, including embolization and stent placement, also play a key role in disease management.

Isolated duodenal duplication cyst presenting as a complex solid and cystic mass in the upper abdomen

Duodenal duplication cysts are a rare subtype of gastrointestinal duplications cysts. Approximately 5% of gastrointestinal duplication cysts occur in the duodenum. An 18-year-old woman presented with epigastric pain and a subjective abdominal bulge. A computed tomography scan was subsequently performed and showed a solid and cystic mass with wall calcifications in the lesser sac of the upper abdomen. A duodenal duplication cyst was found unexpectedly on histopathologic analysis. This was also an unusual case as there was no evidence of malignancy. Four years after surgery, the patient remains asymptomatic. We present a brief literature review on duodenal duplication cysts and discuss its differential diagnosis.

Primary hepatic benign schwannoma

Schwannoma is predominantly a benign neoplasm of the Schwann cells in the neural sheath of the peripheral nerves. Occurrence of schwannoma in parenchymatous organs, such as liver, is extremely rare. A 64-year-old man without neurofibromatosis was observed to have a space-occupying lesion of 23mm diameter in the liver during follow-up examination for a previously resected gastrointestinal stromal tumor (GIST) in the small intestine. He underwent lateral segmentectomy of the liver under a provisional diagnosis of hepatic metastatic recurrence of the GIST. Histological examination confirmed the diagnosis of a benign schwannoma, confirmed by characteristic pathological findings and positive immunoreactions with the neurogenic marker S-100 protein, but negative for c-kit, or CD34. The tumor was the smallest among the reported cases. When the primary hepatic schwannoma is small in size, preoperative clinical diagnosis is difficult. Therefore, this disease should be listed as differential diagnosis for liver tumor with clinically benign characteristics.

Liver schwannoma: findings on MRI

Magnetic resonance imaging features of benign liver schwannoma in a 52-year-old woman are described. An oval shaped, 4.4x3.6x2.9-cm lesion was located in Segment 7 of the right hepatic lobe. The lesion was hypointense on T(1)-weighted images and mixed hypo- and hyperintense on T(2)-weighted images. On serial contrast-enhanced images, the lesion revealed gradually increasing centrilobular enhancement. The tumor was surgically removed thereafter.