Salivary duct carcinoma. Part I. A clinicopathologic evaluation and DNA image analysis of 13 cases with review of the literature.

Salivary duct carcinoma is an uncommon and relatively unknown clinically aggressive adenocarcinoma of salivary origin that histologically demonstrates a remarkable resemblance to invasive carcinoma of the breast. We report the clinicopathologic features of 13 cases that were also examined by image analysis for DNA ploidy. The results were then analyzed collectively with the less than 100 cases of salivary duct carcinoma reported in the English-language literature to define the characteristics of this unusual neoplasm. The 12 men and one woman averaged 68 years of age (range, 49 to 90 years). All tumors arose in the parotid (10 cases) or submandibular glands (three cases). Nine tumors were aneuploid, three diploid, and one was indeterminate because of insufficient tissue. Follow-up (median, 24 months) was available in 12 cases: three patients died of disease, six were alive without disease, and three died of other causes. Combining our cases with those in the literature, a total of 104 cases, confirms that salivary duct carcinoma is a highly malignant neoplasm with distinctive clinical and pathologic features. It arises almost exclusively in the major salivary glands (96% of cases), is three times more common in men, and usually occurs in patients over 50 years of age (range, 22 to 91 years). One-third of patients experience local recurrences, 59% develop positive regional lymph nodes, 46% have systemic metastases (lungs and bones), and 65% die of their disease, usually within 4 years of diagnosis. Determination of tumor ploidy has no prognostic significance. The presence of distant metastasis was the only clinicopathologic feature that was statistically associated with prognosis (p = 0.02); all patients with systemic metastasis died of disease.