Salivary duct carcinoma. Clinicopathologic and immunohistochemical review of 26 cases.

BACKGROUND: Salivary duct carcinoma (SDC) is a high grade aggressive malignancy of the major salivary glands. Clinical and pathologic features that may be predictive of survival are not well delineated. The microscopic features of SDC are remarkably similar to those of mammary ductal carcinoma, raising the question of whether these tumors share antigenic or hormonal features.

METHODS: We reviewed the clinical and pathologic characteristics of 26 cases of SDC treated at the Mayo Clinic from 1960 to 1989. Immunoperoxidase studies and flow cytometry were performed in 25 and 24 cases, respectively.

RESULTS: The study population consisted of 22 men and 4 women (mean age, 66 years). The parotid gland was involved in 23 patients and the submaxillary gland in 3. Five of 24 tumors studied were diploid (21%), and 19 (79%) were nondiploid. Nine tumors (35%) recurred locally and 16 (62%) metastasized distantly; 20 patients (77%) died of disease at a mean interval of 3 years after diagnosis. Female sex was the only significant negative prognostic factor analyzed, but positive nodal status approached significance. Paraffin-section immunostaining showed positive reactions for epithelial membrane antigen (100%), keratin (AE1/AE3) (88%), alpha-lactalbumin (88%), GCDFP-15 (76%), and carcinoembryonic antigen (72%); S-100 protein was rarely detected (4%). Stains for estrogen receptor were uniformly negative, but one tumor was positive for progesterone receptors.

CONCLUSIONS: The prognosis for SDC is dismal, and clinically useful prognostic factors were not found. Our results do not confirm hormonal concordance between SDC and breast carcinoma.