Cystadenoma Arising from the Retromolar Region: a Case Report

Cystadenoma Arising from the Retromolar Region: A Case Report

Yoshihiro Takahashi1, Kenji Kawano1, Shigetaka Yanagisawa1 and Shigeo Yokoyama2

1Department of Oncological science (Oral and Maxillofacial Surgery), Faculty of Medicine, Oita University 2Department of oncological science (Pathology), Faculty of Medicine, Oita University

Abstract: Cystadenoma is an uncommon benign epithelial neoplasm. Cystadenoma usually occurs on the palatal and buccal mucosa, but is less commonly found in the retromolar regions. A 43-year-old male patient noticed a swelling on his gingiva distal to the right mandibular second molar. Physical examination showed a diffuse poorly circumscribed swelling extending from the lingual gingiva distal to the right mandibular second molar to the floor of the mouth and pharynx. The tumor size was 20 × 27 mm. The surface mucosa was purply-blue in parts. About 4 ml of pale yellow serous fluid was aspirated. The tumor was surrounded by a capsule and was excised successfully above the periosteum, incorporating a 2 mm safety margin including the surface mucosa. The tumor consisted of a fibrous capsule with multiple cystic cavities of various sizes. The cysts were lined by a layer of columnar epithelium, with intracystic papillary proliferation in some areas. No cytologic atypia or invasion of the surrounding tissues were observed. There is no evidence of recurrence ten years after excision, suggesting that complete excision is sufficient treatment in such cases.

Key words: cystadenoma, minor salivary gland, retromolar region, serous ﬂuid

Introduction Case Report Cystadenoma is an uncommon benign epithelial A 43-year-old male patient with no contributing neoplasm that can exhibit unilocular or multilocu- medical or family history noticed a swelling on his lar cystic proliferation with intracystic papilla- gingiva distal to the right mandibular second tions. molar in August 199X. He was referred by his Cystadenoma occurs commonly in the parotide. dentist to our institution on September 199X. In the minor salivary glands, cystadenoma are Physical examination showed a diffuse poorly cir- located in the lip and buccal mucosa, but is less cumscribed swelling extending from the lingual commonly found in the retromolar regions. We gingiva distal to the right mandibular second report a case of a cystadenoma arising from the molar to the ﬂoor of the mouth and pharynx (Fig. retromolar region. 1). The tumor size was 20 × 27 mm. The surface mucosa was purply-blue in parts. It was elastic, Received 8/29/06; revised 3/14/08; accepted 3/21/08. soft and ﬂuctuant. There was no induration of the Requests for reprints: Yoshihiro Takahashi, Department of Oncological Science (Oral and Maxillofacial Surgery), Faculty of surrounding tissues. Medicine, Oita University, 1–1 Idaigaoka, Hasama-mach, Yufu-city, No evidence of morphological change in the bone Oita, Japan, Phone: +81–97–586–6702, Fax: +81–97–549–2838, E- mail: [email protected] was observed upon simple radiographic and CT 62 Oral Science International Vol. 5, No. 1

Fig. 1 Clinical appearance of the tumor in the retromolar region.

examinations. A clinical diagnosis of the benign tumor or cyst was made, and a puncture aspiration was performed during the first visit. About 4 ml of pale yellow serous fluid was aspirated. A biopsy was performed on the same day. Histopathologically, the biopsy revealed a ductal structure with papillary proliferation, lined by cuboidal or columnar epithelium without atypia. A pathological diagnosis of monomorphic adenoma was made. The patient was admitted to our hospital on October 199X, and five days later the right mandibular third molar was extracted and the tumor was excised. The tumor was surrounded by a capsule and was excised successfully above the periosteum, incorporating a 2 mm safety margin including the surface mucosa. Since slight bone resorp- tion was observed on the surface of the cortical bone induced by the pressure of the tumor, the surface of the bone was removed with a round bur. Fig. 2 Histopathological findings of cystadenoma. The tumor consisted of a fibrous capsule with (a) The tumor consisted of a fibrous capsule with multiple cystic cavities of various sizes multiple cystic cavities of various sizes (Fig. 2a). (hematoxylin and eosin stain loupe view- The cysts were lined by a layer of columnar epi- ing). (b) The tumor was composed of several large cystic spaces (hematoxylin and eosin thelium, with intracystic papillary proliferation in stain, original magnification ×40). (c) The some areas (Fig. 2b, c). No cytologic atypia or columnar epithelium showed a papillary invasion of the surrounding tissues were observed. form in the cystic spaces with limited in- traluminal growth (hematoxylin and eosin The postoperative histopathological diagnosis was stain, original magnification ×200). cystadenoma. There has been no evidence of recurrence ten years after excision. exhibiting intracystic papillary proliferation1,2. Discussion Chaudhry et al. (1984) reported having observed Cystadenoma arising from an intraoral minor four cases of the tumor (7.6%) among 189 intraoral salivary gland is an uncommon benign neoplasm minor salivary gland tumors3. Waldron et al. May, 2008 Cystadenoma Arising from the Retromolar Region 63

(1988) reported the occurrence of 20 cases out of intraductal papilloma. Warthin's tumor consists 426 intraoral minor salivary gland tumors4. This of an oncocytic epithelial component and a lym- translates to 4.7% of the total number of minor phoid component. Papillations are lined by a dou- salivary gland tumors and 8.1% of the benign ble layer of columnar and cuboidal cells with minor salivary gland tumors. Crocker et al. (1970) eosinophilic cytoplasm. This epithelium is charac- diagnosed two cases of the tumor (7.7%) out of 26 terized by its prominent lymphoid infiltrate in the intraoral minor salivary gland tumors5. Morimoto subepithelial regions2,9–11. We found no prolifera- et al. (1977) reported one case of the tumor among tion of lymphoid cells in our case. 57 benign minor salivary gland tumors in Japan6. Intraductal papilloma is a tumor originating Waldron et al. (1988) noted that the mean age from a salivary gland duct, with a characteristic for patients with papillary cystadenoma in their unilocular appearance. This is in contrast to cys- study was 63.7 years, with a 3:1 majority of tadenoma, which has small cystic cavities and dis- females. They observed lesions on the buccal plays multilocular cystic proliferation, as we found mucosa (7), palate (4), floor of the mouth (3), and in our case. This characteristic is said to be the lower lip (3), but none in the molar regions4. most important in differential diagnosis. Further- Our review of the Japanese literature revealed more, it is important to differentiate low-grade 23 cases of papillary cystadenoma, including our cystadenocarcinoma from cystadenoma. This dis- case. The youngest and oldest patients were 42 tinction can sometimes be difficult because this and 80 years, respectively, and the average age neoplasm shows little cytological atypia2,9–11. In was 58 years. Nine patients were male and 13 our case, the differential diagnosis was made on patients were female. The lesions arose from the the basis of the presence or absence of invasion of buccal mucosa (5), hard palate (5), and retromolar the surrounding tissues. Cystadenoma is sur- region (4). In Japan, 5 out of 23 cases (21.7%) rounded by a fibrous capsule. The tumor gener- involved the retromolar region including our ally does not show evidence of invasion of sur- report. These results indicate a higher rate of rounding tissues, just intracystic proliferation. occurrence in the molar region in Japan compared Because of its frequent recurrence years after with reports from other countries. Most of the surgery, cystadenoma has been presumed to be a reported cases consisted of tumors that were elas- low-grade malignancy. Nevertheless, there is no tic, soft painless masses. The size of the tumors locally destructive behavior in this tumor8–10. His- varied from 0.3 to 3.0 cm. A clear viscous fluid tologically, cellular atypia and mitotic figures are was present in the cysts of two reported cases, and absent. In addition, there have been no reports of in our case the cyst was found to contain a pale metastasis. Alexis et al. (1995) suggested that yellow serous fluid. incomplete excision of this tumor could result in Histopathologically, the tumor often is sur- recurrence11. In our case, the tumor was excised rounded by a fibrous capsule containing cystic with extraction of the third molar and the removal spaces of various sizes. In addition, the tumor is of the surface bone below the tumor. Since neither characterized by intracystic papillary prolifera- cellular atypia nor mitotic figures were observed, tion. The tumor cells have eosinophilic cytoplasm, we did not undertake any postoperative treat- and goblet cells may be present. Mucous cells are ment. There is no evidence of recurrence ten rarely observed. The cystic cavities are lined by years after excision, suggesting that complete columnar epithelium, with some mucous cells in excision is sufficient treatment in such cases. our case. Periodic Acid-Schiff (PAS) or Alcian Blue stain may be performed to confirm the existence of References 8–10 mucus-producing cells . So far, no unique mark- 1. Skalova A., and MIchal M.: Pathology and Genetics of ers have been found. Head and Neck Tuours. World Health Organization Clas- The most important tumors in the differential sification of Tumours; IARC Press, Lyon 2005, pp273–274. diagnosis of cystadenoma are Warthin's tumor and 2. Ellis G.L., and Auclair P.L.: Tumors of the salivary gland. 64 Oral Science International Vol. 5, No. 1

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