Neural and mesenchymal tumours

J. Albores-Saavedra H.R. Menck

J.C. Scoazec N. Soehendra

C. Wittekind P.V.J. Sriram B. Sripa

Paraganglioma

This benign tumour is composed of chief cells and sustentacular cells arranged in a nesting or zellballen pattern. The chief cells are argyrophilic and stain for neuron-specific enolase and chromogranin. The sustentacular cells are S-100 protein positive. The tumour is located in either the subserosa or muscular wall of the gallbladder and apparently arises from normal paraganglia. This rare and small tumour is usually an incidental finding in cholecystectomy specimens. Paragan-gliomas also occur in the extrahepatic bile ducts, where they may be symptomatic.

Granular cell tumour

Granular cell tumours are the most common benign non-epithelial tumours of the extrahepatic biliary tract. They are more common in the bile ducts than in the gallbladder. Although usually single, granu lar cell tumours may be multicentric or may coexist with one or more granular cell tumours in other sites, especially the skin.

Ganglioneuromatosis

Ganglioneuromatosis of the gallbladder is a component of the type Ilb multiple endocrine neoplasia syndrome. The histological changes consist of Schwann cell and ganglion cell proliferation in the lamina propria as well as enlarged and distorted nerves in the muscle layer and subserosa. Neurofibromatosis is exceedingly rare in the gallbladder but has been reported in association with multiple neu-rofibromatosis.

Embryonal rhabdomyosarcoma ('sarcoma botryoides') is the most common malignant neoplasm of the biliary tract in childhood. It occurs more frequently in the bile ducts than in the gallbladder. Kaposi sarcoma of the extrahepatic bil iary tract is an incidental autopsy finding in the acquired immune deficiency syndrome. The haemorrhagic lesions are usually located in the subserosa or muscular wall of the gallbladder or in the periductal connective tissue of the bile ducts. Other malignant non-epithelial tumours are leiomyosarcoma, malignant fibrous histiocytoma and angiosarcoma. Leiomyoma, lipoma, haemangioma, and lymphangioma have been described. A benign stromal tumour of the gallbladder with interstitial cells of Cajal phenotype has been reported recently {35}.

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