ORIGINAL ARTICLE Sclerosing Polycystic Adenosis of the Salivary Gland A Report of 16 Cases Douglas R. Gnepp, MD,* Li J. Wang, MD, PhD,* Margaret Brandwein-Gensler, MD,† Pieter Slootweg, MD,‡ Melissa Gill, MD, k and Jos Hille, DDS, MDent, FCPath (SA)§ Abstract: Sclerosing polycystic adenosis is a recently described, extremely rare, reactive, sclerosing, inflammatory process somewhat similar to fibrocystic changes and adenosis tumor of the breast. To date, there have been 22 cases described in the literature. Because of the infrequency of this lesion, we describe our combined experience with 16 cases, 1 of which has been previously reported. Thirteen tu- mors arose in the parotid gland, two involved the submandibular gland, and one arose in the buccal mucosa. There were 9 men and 7 women. Patients ranged in age from 9 to 75 years. Fourteen patients presented with a primary mass. Two were incidental findings in patients with a mixed tumor and an oncocytoma. Tumors ranged in size from 0.3 to 6 cm in greatest dimension. They are typically well circumscribed and are composed of densely sclerotic lobules with prominent cystic change. Hyperplasia of ductal and acinar elements and areas of apocrine-like metaplasia are frequent. Foci with mild ductal epithelial atypia were frequent with .50% of cases demon- strating at least focal areas of duct epithelial hyperplasia with atypia. Follow-up ranged from 1.5 to 40 years. One tumor recurred twice; no patient has developed metastases or died of disease. Key Words: salivary gland, adenosis, atypia, cystic, sclerosing (Am J Surg Pathol 2006;30:154–164) S clerosing polycystic adenosis (SPA) is a recently described, rare, reactive, inflammatory process of the major or minor salivary glands that is similar to fibrocystic changes, sclerosing adenosis, and adenosis tumors of the breast. Smith et al first reported SPA in 1996. 10 They described 9 patients from the Armed Forces Institute of Pathology. Since this initial report, there have been several smaller series with a total of 22 pub- lished case reports to date. 1–3,5,8,9,10 Occasional cases demon- strate atypia, and recently several tumors with severe dysplastic change/carcinoma in situ have been reported. 8,9 Slightly less than 30% of tumors have recurred and, to date, none has behaved aggressively. 4 Because of the rarity of this lesion, we have reviewed our experience with 16 patients, the largest series in the literature to date. MATERIALS AND METHODS Archival tissue in the authors’ institutional and con- sultation files with diagnoses of SPA, sclerosing polycystic sialadenopathy, and sclerosing sialadenitis were retrieved and reviewed. Sixteen patients were identified (D.R.G. [10 cases], M.B.G. [2 cases], and P.S. [4 cases]). Hematoxylin and eosin stained slides were available on every case. Mucicarmine and PAS-stained slides with and without diastase digestion were also available in 5 and 6 cases, respectively. Standard immuno- histochemistry was performed in 7 tumors for calponin (6 cases), smooth muscle actin (7 cases), S-100 (2 cases), and muscle specific actin (1 case) to evaluate for the presence of a myoepithelial cell layer around the periphery of tumor nests. Contributors were contacted for patient follow-up information. RESULTS Clinical Features Sixteen patients with SPA were identified in the authors’ files (Table 1). The series compromised 9 men and 7 women. Thirteen tumors arose in the parotid gland, two in the sub- mandibular gland, and one in the buccal mucosa. Fifteen pa- tients ranged in age from 9 to 75 years (mean, 44.5 years) and 1 patient was ‘‘middle aged.’’ Four patients werewhite; racial information was not available in 12 patients. Fourteen patients presented with a primary lesion with histories of a slow- growing mass. Three of these patients had associated pain or tenderness, and 1 patient also had a subjacent combined se- baceous lymphadenoma and Warthin tumor.Two patients had incidental lesions: one was associated with a recurrent benign mixed tumor and the other with an oncocytoma. The latter patient also had a benign mixed tumor in the adjacent sub- mandibular gland. Patients were treated with parotidectomy (11 patients) or submandibular gland excision (2 patients); two parotid tumors and the buccal mucosa lesion were locally excised. Follow-up information ranging from 1.5 to 40 years (mean, 8.5 years) was available in 15 patients. One was a recent case. One patient, treated with local excision, developed 2 recurrences From *Brown University School of Medicine, Rhode Island Hospital, Prov- idence, RI; †Montefiore Medical Center, Moses Division, Albert Einstein College of Medicine, Bronx, NY; ‡Department of Pathology, Radboud University Medical Center, Nijmegen, the Netherlands; §University of the Western Cape/National Health Laboratory Services, Cape Town, South Africa; and k Weil Cornell Medical Center, New York, NY. Reprints: Douglas R. Gnepp, MD, Rhode Island Hospital, Department of Pathology, APC 12, 593 Eddy St., Providence, RI 02903 (e-mail: DGnepp@Lifespan.org). Copyright Ó 2006 by Lippincott Williams & Wilkins 154 Am J Surg Pathol  Volume 30, Number 2, February 2006 Copyright ' Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.