[HIV-associated cysts of the parotid glands. An histomorphologic and magnetic resonance tomography study of formal pathogenesis].

BACKGROUND

Multiple and bilateral parotid Lymphoepithelial cysts (LEC) are encountered in 3-6% of HIV-infected patients. The formal pathogenesis of LEC is controversial. They are thought to develop from embryological salivary gland inclusions in intraparotid lymphnodes.

METHODS

Seventeen operative parotid specimens from HIV-infected patients were examined histologically and immunohistologically. Findings of magnetic resonance imaging (MRI) were correlated with the histological results.

RESULTS

A continuous spectrum of a lymphoepithelial salivary gland lesion is found, developing initially from a lymphoid infiltration of salivary lobules to lymphoepithelial duct lesions with cystic dilatation up to large ductal cysts (diameter up to 3.5 cm) with highgrade parenchymal atrophy. The ductal and cystic lesions demonstrate an intense basal cell hyperplasia without participation of myoepithelial cells. The MRI findings indicate involvement of the entire tissue of both parotid glands.

CONCLUSIONS

The preferred hypothesis of a development of HIV-associated Lymphoepithelial cysts from preexisting salivary lymphnode inclusions cannot be verified. Our results demonstrate a continuous development of the cysts from a Sjögren-like cystic lymphoepithelial lesion of parotid glands. The enormous cystic dilatation of the duct lesions presumably is a consequence of ductal obstruction through basal cell hyperplasia of striated ducts and intense intraglandular lymphofollicular hyperplasia.