Examination showed a non tender swelling with variegated consistency in parotid region raising the ear lobule. Overlying skin showed dilated veins. The swelling was partly fixed to underlying structures and clinically there was no evidence of facial nerve involvement. There were no palpable cervical lymph nodes and haematological and biochemical investigation were within normal limits. A fine needle aspiration cytology (FNAC) was carried out which was suggestive of pleomorphic adenoma. With a diagnosis of pleomorphic adenoma patient underwent parotidectomy.

On gross examination the parotidectomy specimen measured 7 × 5 × 2 cm with irregular and nodular surface. Cut section showed grey white appearance with cystic spaces and foci of haemorrhage and calcification. Microscopic examination of the sections from salivary gland revealed partially circumscribed neoplasm (Figure ​(Figure1)1) composed of numerous duct like structures and cystic spaces lined by flat to cuboidal epithelium and filled with keratin flakes intricately mixed with lymphoid stroma showing follicular formation in areas (Figure ​(Figure2).2). Duct like space were lined by outer basaloid cells and inner mature sebaceous cells were present (Figure ​(Figure3)3) focal squamous and mucinous metaplasia of lining epithelium was also seen along with areas of fibrosis and calcification. In one area neoplasm was seen to arise from lining epithelium of duct like spaces composed of polygonal cells with moderate cytoplasm and hyperchromatic pleomorphic nuclei, arranged in sheets, nests and group foci of keratinsation seen in between cell groups (Figure ​(Figure4).4). A diagnosis of sebaceous lymphadenoma with moderately differentiated squamous carcinoma was made.

Microscopy in sebaceous lymphadenoma show variable sized sebaceous glands admixed with salivary ducts surrounded by dense lymphoid stroma. Lymphoid background has well developed germinal centres. Histiocytes, foreign body giant cell and inflammatory reaction are seen. Focal necrosis can be observed occasionally [2,3]

Histogenesis of Sebaceous lymphadenoma is unclear. Possible theories are that it develops within the ectopic salivary gland in intraparotid lymph node [1] or may arise due to sebaceous differentiation in other tumours [1,4]. Other tumours to consider with similar histological characteristic include tumours with focal sebaceous differentiation, Warthin's tumour, mucoepidermoid carcinoma, pleomorphic adenoma (malignant), adenoid cystic carcinoma, benign oncocytoma and basal cell adenoma. [5,6]

Malignant transformation of the sebaceous lymphadenoma, although rare, should be considered along with possibility of a synchronous second primary malignant neoplasm in enlarging, locally invasive parotid lesions, considering that clinical behaviour and prognosis will be determined by the nature of the malignant component [7-9].