Clear cell hidradenoma: An unusual tumor of the oral cavity
A 67-year-old, well-oriented, otherwise normal, female patient presented with an asymptomatic swelling in her left cheek of 5-month duration. Intra-oral examination revealed a solitary, well-defined, submucosal nodule measuring around 2 × 2 cm, with intact mucosa unattached to the lesion. This led to the clinical diagnosis of a lipoma. Other differential diagnoses included fibroma and cysticercus cellulose owing to the details of regular use of ham in diet history.\nA firm nodule was surgically excised under local anaesthesia in toto. Macroscopic examination showed, an oval shaped solitary lesion, whitish in color, firm in consistency, measuring around 1.5 × 1 cm. The lesion was cystic and filled with yellow, viscous, odorless fluid with white flecks []. Cystic fluid was smeared on glass slide and stained with H and E, which revealed epidermoid cells on a background of eosinophillic fibrillar material similar to keratin.\nMicroscopic evaluation of H and E stained slides revealed cystic lesion showing well defined tumor lobule composed of cellular masses separated by collagenous stroma. The tumor was made up of two type of cell population []. The predominant type of cell was epidermoid with faintly eosinophillic granular cytoplasm and round nucleus. The other type of cell was a large round clear cell with small dark nuclei, found along with duct like spaces []. Cystic areas at few places were lined by 1-3 layer of flat to cuboidal epithelium []. Few areas in the stroma showed chronic inflammatory cells and melanin pigment []. The sections stained with Periodic Acid Schiff [PAS] showed clear cells positive for the stain. All these above features were suggestive of a benign CCH.