SALIVARY DUCT CARCINOMA - A HIGHLY AGGRESSIVE SALIVARY-GLAND TUMOR WITH OVEREXPRESSION OF C-ERBB-2

The clinicopathological and immunocytochemical features of nine cases of salivary duct carcinoma are described. This relatively rare tumour, which only recently has been widely recognized as a separate entity, is highly malignant and caused the death in eight of the patients. The tumour cells are arranged in cribriform and solid growth patterns, wh ere the solid tumour nests frequently have comedo necrosis, and a fibr ous, often sclerotic, stroma is present. The infiltrating desmoplasmic component and the diffuse invasive growth into adjacent adipose parot id tissue have similarities to ductal breast carcinoma. Immunocytochem ical investigation of salivary duct carcinoma showed constant overexpr ession of c-erbB-2 as detected by membrane accentuation, and high prol iferative activity as detected by nuclear positivity for MIB 1 (Ki-67) . Changes in the expression of p53 and retinoblastoma gene product do not constitute a constant event in salivary duct carcinoma. A few of t he tumours showed scattered cells with distinct nuclear positivity for both progesterone and oestrogen receptors. We emphasize that this hig hly malignant salivary gland tumour has a characteristic morphology, m ay not be as rare as previously considered, and that prompt and aggres sive therapy is needed.