S. Ihrler et al., HIV-ASSOCIATED CYSTS OF THE PAROTID-GLAND S - A STUDY WITH HISTOMORPHOLOGY AND MAGNETIC-RESONANCE-IMAGING ADDRESSED TO FORMAL PATHOGENESIS, Laryngo-, Rhino-, Otologie, 75(11), 1996, pp. 671-676
Background: Multiple and bilateral parotid Lymphoepithelial cysts (LEC
) are encountered in 3-6% of HIV-infected patients. The formal pathoge
nesis of LEC is controversial. They are thought to develop from embryo
logical salivary gland inclusions in intraparotid lymphnodes. Methods:
Seventeen operative parotid specimens from HIV-infected patients were
examined histologically and immunohistologically. Findings of magneti
c resonance imaging (MRI) were correlated with the histological result
s. 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 dilatat
ion up to large ductal cysts (diameter up to 3.5 cm) with high-grade p
arenchymal atrophy. The ductal and cystic lesions demonstrate an inten
se basal cell hyperplasia without participation of myoepithelial cells
. The MRI findings indicate involvement of the entire tissue of both p
arotid glands. Conclusions: The prefered hypothesis of a development o
f HIV-associated Lymphoepithelial cysts from preexisting salivary lymp
hnode inclusions cannot be verified. Our results demonstrate a continu
ous development of the cysts from a Sjogren-like cystic lymphoepitheli
al lesion of parotid glands. The enormous cystic dilatation of the duc
t lesions presumably is a consequence of ductal obstruction through ba
sal cell hyperplasia of striated ducts and intense intraglandular lymp
hofollicular hyperplasia.