SCLEROSING POLYCYSTIC ADENOSIS OF MAJOR SALIVARY-GLANDS - A CLINICOPATHOLOGICAL ANALYSIS OF 9 CASES

We describe nine cases of a histologically distinct and previously unr eported lesion of the major salivary glands. The patients ranged in ag e from 12 to 63 years and included four males, five females. The lesio ns were slow-growing masses in the parotid gland (eight cases) and sub mandibular gland (one case). The clinical impression in each case was a benign salivary gland tumor. Grossly, the lesions were discrete, pal e, rubbery nodules embedded within the salivary gland parenchyma. Micr oscopically, the lesions were unencapsulated, circumscribed masses of sclerotic and hyalinized collagenous tissue. Irregularly distributed t hroughout the collagenous tissue in a vaguely lobular pattern were hyp erplastic ductal and acinar elements that were usually accompanied by cystically ectatic ducts. The dilated ducts frequently showed apocrine -like metaplasia and epithelial hyperplasia, which often formed transl uminal bridges in a cribriform pattern. This epithelial hyperplasia so metimes surrounded eosinophilic globules as seen in so-called collagen ous spherulosis. The combination of fibrosis, epithelial hyperplasia, and cystic changes were reminiscent of fibrocystic changes of the brea st. Focally, acinar elements contained large, intensely eosinophilic, periodic acid-Schiff's-positive, intracytoplasmic granules believed to represent altered zymogen granules. A sparse to focally intense lymph ocytic infiltrate accompanied the epithelial proliferations. Previous interpretations of these masses have included mucoepidermoid carcinoma , low-grade adenocarcinoma, benign adenoma, and mixed tumor. The limit ed available follow-up suggests that this process has a favorable prog nosis despite recurrences in two cases. It is postulated that these le sions represent a pseudoneoplastic condition that results in both fibr osis and epithelial proliferation. We suggest the term sclerosing poly cystic adenosis for these rare lesions.