SWEAT GLAND CARCINOMA - A CLINICOPATHOLOGICAL ANALYSIS OF AN EXPANDEDSERIES IN A SINGLE INSTITUTION

Primary adenocarcinoma of sweat glands is a rare tumor; approximately 220 cases have been reported in the last 30 years. We reviewed the cha rts of patients with primary diagnosis of this tumor treated at the Ma yo Clinic between 1935 and 1995. We included only cases with initial h istology slides available for I e-examination. Tumors were classified into five recognizable histologic patterns (solid, ductal, mucinous, m icrocystic adnexal, and adenocystic carcinoma) and graded by the Brode r system. Statistical analysis consisted of Kaplan-Meier product limit method and Cox multiple regression test. In total, 55 patients were i dentified, and age ranged from 13 to 85 years (mean 59 years). Thirty- six patients (65 percent) presented to the Mayo Clinic for initial tre atment; all except one had disease limited to the primary site. Microc ystic adnexal carcinoma was the most frequent type, and more than 50 p ercent were grade 2 tumors. among these 36 patients, 4 had some type o f recurrence. Patients who developed metastasis had a high-grade tumor in the initial biopsy. Nineteen patients were referred with recurrenc e; 13 had local recurrence, 4 had regional diseases, and 2 had distant metastases. The histologic distribution showed 47 percent solid tumor s, and 37 percent of them were grade 3. Multiple regression analysis d id not show a difference in recurrence or survival when gender, age, t umor location, or histologic pattern was evaluated. In addition, there was no difference in the outcome between wide surgical resection and micrographic surgery. The only predictive factor for distant metastase s and/or death (p < 0.003) was histologic grade. Overall 10-year survi val rate was 86 and 60 percent for primary and referred patients, resp ectively. We conclude that histologic diagnosis of sweat gland carcino ma must be complemented by clinical examination to evaluate metastases . Clinical behavior depends on the histologic type of tumor, degree of differentiation, and clinical stage. On recurrence, the likelihood of fur ther recurrences and mortality increases dramatically. aggressive initial local ablation with tumor-free margins is recommended. In hig h-grade tumors, prophylactic regional lymph node dissection may furthe r characterize tumor aggressiveness and may justify adjuvant radiother apy as part of the primary treatment.