CASE REPORT

Basal Cell Adenoma of Hard Involving Maxillary Alveolus Manas Bajpai, Nilesh Pardhe, Betina Chandolia and Manika Arora

ABSTRACT Basal cell adenomas (BCA) are unusual benign tumors of salivary glands and are most often located in the . Minor salivary glands are relatively rare location for these tumors. Microscopically, they are composed of isomorphic cells, similar to basaloid cells with palisading arrangement and distinctive basement membrane like material. Herein, we report a case of BCA presenting as a soft tissue growth of left hard palate involving maxillary alveolus of a 41-year male.

Key Words: Basal cell adenoma. Palate. Monomorphic adenoma. Minor salivary gland.

INTRODUCTION reddish patches and the base was covered by yellowish Basal cell adenoma (BCA), classified as part of the crust (Figure 1a). Radiographic examination showed category of monomorphic adenomas, was first that the swelling was not associated with alveolar bone. described and adequately documented as a distinct On palpation the growth was found to be firm. General clinico-pathological entity by Kleinsasser and Klein in and family history was non-contributory to the present 1967.1 BCA as defined by WHO, is a distinctive benign swelling. neoplasm composed of basaloid cells organized with a Based on above features, a provisional diagnosis of prominent basal cell layer and distinct basement was made with the differential membrane-like material and no myxochondroid stromal diagnoses of fibroma and peripheral giant cell component as seen in pleomorphic adenomas.2 The granuloma. Surgical excision of the lesion was done most common site of occurrence is parotid gland under local anesthesia and tissue was sent to the followed by upper , palate, buccal mucosa and lower department of Oral and Maxillofacial Pathology, NIMS lip.3 Clinically, they present as slow growing, movable, Dental College, Jaipur for histopathological evaluation round or oval masses.4 Histologically, they are divided (Figure 1b). Histopathological examination of the into four subtypes; solid, tubular, membranous and specimen revealed solid nests of isomorphic basaloid trabecular.4,5 cells, separated by basement membrane like material. Intraorally, palate is one of the rarest site for BCA; an exhaustive review of English literature could reveal only six cases of palatal BCA. The case is being presented here because of its rare location.

CASE REPORT A 41-year male presented to the Department of Oral Medicine and Radiology, NIMS Dental College, Jaipur, Figure 1: (a) Clinical picture of the lesion, (b) Gross specimen. India, for the evaluation of a painless soft tissue growth on right side of his hard palate for 4 months. The swelling was asymptomatic and not associated with any systemic changes. Intraoral examination exhibited an oval soft tissue growth extending from the left side of hard palate to the alveolar ridge with relation to the distal aspect of the maxillary right second molar, measuring about 2 x 2 cm. The swelling was pink in color with few

Department of Oral and Maxillofacial Pathology, NIMS Dental College, Jaipur, India. Correspondence: Dr. Manas Bajpai, Associate Professor, Department of Oral and Maxillofacial Pathology, NIMS Dental Figure 2: (a) Nests of isomorphic cells separated by basement membrane College, Jaipur, India. like material with prominent vascular channels lined by endothelial cells E-mail: [email protected] (Hematoxylin and Eosin stain X20). (b) High power view shows monomorphic basaloid cells with round hyperchromatic nuclei arranged in a palisading Received: June 20, 2016; Accepted: June 05, 2017. pattern. (Hematoxylin and Eosin stain X 40).

S108 Journal of the College of Physicians and Surgeons Pakistan 2017, Vol. 27 (Special Supplement 2 of Case Reports): S108-S109 Basal cell adenoma of hard palate involving maxillary alveolus

The stroma showed vascular channels lined by endothelial complete surgical removal of the tumor is mandatory. cells (Figure 2a). The basaloid cells contained round and The same treatment approach was performed in the hyperchromatic nuclei and showed a palisaded present case; and 1-year follow-up of the patient was arrangement (Figure 2b). On the basis of histo- uneventful. pathological features, a final diagnosis of BCA was BCA of minor salivary glands is a rare tumor; and rendered. One year follow-up of the patient was because of its rare occurrence, careful differentiation of uneventful. this tumor from malignant tumors like is necessary before treatment. A complete DISCUSSION surgical excision and a careful follow-up are mandatory because of high recurrence rate. Although it is a rare Salivary gland tumors arising intraorally are unusual and tumor of palate, it needs to be kept in the differential constitute 2 - 6.5% of all head and neck neoplasms.6 diagnosis of palatal swellings. BCAs, once considered as a type of monomorphic adenoma; but as per revised WHO classification of salivary gland tumors (1991), are now included in the REFERENCES benign salivary gland neoplasm with the exclusion of 1. Bajpai M. Canalicular adenoma arising in buccal mucosa. word monomorphic.2 They account for 1-3% of all J Coll Physicians Surg Pak 2016; 26:946. epithelial salivary gland neoplasms.1 They are most 2. Gardner DG, Daley TD. The use of the terms monomorphic often located in the parotid gland (superficial lobe).7 The adenoma, basal cell adenoma, and canalicular adenoma as minor salivary glands are a relatively rare location for applied to salivary gland tumors. Oral Surg Oral Med Oral Pathol these tumors and in minor salivary glands, upper lip is 1983; 56:608-615. the commonest site.2,3 The present case is very rare and 3. Hemachandran M, Lal A, Vaiphei K. Basal cell adenoma – an only the 7th reported case of BCA, located on the palate. unusual presentation. Ann Diagn Pathol 2003; 7:292-5. BCA shows a slight female predilection and the mean 4. Esteves AR, Dib LL, de Carvalho LV. Basal cell adenoma: age of occurrence is 57.7 years.4 However, the present a case report. J Oral Maxillofac Surg 1997; 55:1323-5. case was contrary, as it was reported in a 41-year male. 5. Gupta N, Jadhav K, Ahmed MB, Amberkar VS. Basal cell adenoma in a relatively rare site. J Oral MaxillofacPathol. 2009; Histologically, it has four variants; solid, tubular, 13:101-4. trabecular, and membranous; solid being the most 3 6. Jang M, Park D, Lee SR. Basal cell adenoma in the parotid common, but each tumor has combination type. In spite gland: CT and MR findings. Am J Neuroradiol. 2004; 25:631-5. of specific histological features, other primary tumors 7. Fantasia JE, Neville BW. Basal cell adenomas of the minor like adenoid cystic carcinoma and pleomorphic salivary glands. A clinicopathologic study of seventeen new adenoma may masquerade as BCA. The recurrence casesand a review of the literature. Oral Surg Oral Med Oral rate of membranous variant of BCA is 25 - 37%.2 The Pathol 1980; 50:433-40. tumor does not undergo malignant transformation; 8. Nagao T, Sugano I, Ishida Y, Matsuzaki O, Konno A, Kondo Y, although one case of BCA that underwent malignant et al. Carcinoma in basal cell adenoma of the parotid gland. transformation, has been reported in the literature.8 A Pathol Res Pract 1997; 193:171-8.

Journal of the College of Physicians and Surgeons Pakistan 2017, Vol. 27 (Special Supplement 2 of Case Reports): S108-S109 S109