Sclerosing polycystic adenosis is a recently described, extremely rare, reactive sclerosing inflammatory process somewhat similar to adenosis tumor of the breast. To date, 31 cases have been described in the literature. Twenty-seven tumors involved the parotid gland, two involved the submandibular gland, and two arose within the oral cavity in minor salivary gland sites. Patients ranged in age from 9 to 80 years, with an approximate 2.5:1 female-to-male incidence. Primary tumors range in size from 1 to 7 cm in greatest dimension, are typically unencapsulated, and are composed of densely sclerotic lobules with prominent cystic change. Hyperplasia of ductal and acinar elements and areas of apocrine-like metaplasia are typical. Foci with dysplasia of ductal epithelium ranging from mild dysplasia to occasional cases with carcinoma in situ are moderately frequent. Invasive carcinoma has not been reported in these patients. Tumors in 5 (29%) of the 16 patients with follow-up have recurred. To date, no patients have developed metastases or have died from disease.