DIFFERENTIAL-DIAGNOSIS OF SQUAMOUS-CELL C ARCINOMA OF THE SALIVARY-GLANDS

Primary squamous cell carcinomas (SCC) of the salivary glands are loca lized predominantly in the major salivary glands and must be distingui shed from metastases of extraglandular SCC of the skin,especially the head and neck area. Squamous cell metaplasia in non-tumourous diseases of the salivary gland (e.g. necrotizing sialometaplasia) as well as i n benign or malignant salivary gland tumours (e.g., metaplastic Warthi n tumour) can simulate SCC. Other differential diagnostic problems are the structural variants of SCC which develop predominantly in the min or salivary glands, but not in the major salivary glands. Special type s include the very rare adenoid SCC with pseudoglandular structures as the result of acantholysis, the biphasic adenosquamous carcinoma with differentiation as SCC and adenocarcinoma, the biphasic basaloid squa mous carcinoma with a structure as SCC and solid basaloid carcinoma (a nalogous to the solid type of adenoid-cystic carcinoma) and the poorly differentiated mucoepidermoid carcinoma (grade III) with biphasic str ucture of undifferentiated epidermoid and intermediate cells as well a s inclusion of small groups of mucous-producing goblet cells. The diff erential diagnostic criteria are analysed concerning prognosis and tre atment.