Malignant Oncocytoma of a Minor Salivary Gland: An Unusual Presentation at the Base of the Tongue

Abstract

In contrast to malignant oncocytomas of the parotid gland, malignant oncocytomas arising from minor extraparotid glandular tissue are rare. The latter may display a locally aggressive behaviour as well as a variable tendency to develop secondary cervical lymph nodes. We report a new case of malignant oncocytoma in a 43-year-old man presenting with greatly enlarged cervical lymph nodes accompanied by a poorly defined swelling at the base of the tongue microscopically identified as a malignant oncocytoma. The diagnosis was strongly supported by the ultrastructural features of the cells almost completely filled with mitochondria. The cervical mass was excised, and the patient has suffered no recurrence for nearly 2 years after surgical treatment.

Nonparotid parapharyngeal oncocytoma: A case report and literature review

“…It is a tumor usually seen in older persons and with no predilection for either sex 1. They are most commonly found in the superficial lobe of the parotid,1 but have been reported not only in the submandibular gland2 but also in minor salivary gland tissues of the larynx,3–5 oral cavity,6–8 palate,9, 10 base of tongue,11, 12 nasal cavity,13, 14 paranasal sinuses,15, 16 and masseter 17…”

Oncocytoma of Oral Cavity Mimicking as Jaw Tumor

“…Although oncocytic tumorigenesis secondary to acquired mitochondrial dysfunction is a plausible mechanism, few of these tumors actually harbor mtDNA alterations within the control region [8]. Malignant extra parotid minor salivary gland tumours as compared to parotid malignant oncocytomas present aggressively with multiple cervical lymph node metastasis and cellular ultrastructure had cells filled with mitochondria [9]. Oncocytic adenocarcinoma of parotid gland is more common in the 6th decade of life and later, and those less than 2 cm in size at the initial surgical procedure showed better prognosis [10].…”

Pedunculated oncocytic carcinoma in buccal mucosa: immunohistochemical and ultrastructural studies

“…This cellular change may result from compensation for defects in cellular respiration and other metabolic pathways (Hartwick and Batsakis, 1990) or from mitochondrial division (Tremblay and Pearse, 1959). Mitochondrial oxidative enzymes, such as succinate dehydrogenase (SDH) (Damiani et al , 1998), are highly active in oncocytic cells and stain positive immunohistochemically for CK (Tatemoto et al , 1987; Ruby and Kish, 1996; Gavilanes et al , 2000) and EMA (Tatemoto et al , 1987; Ruby and Kish, 1996), and negatively for S‐100 protein (Sugimoto et al , 1993; Ruby and Kish, 1996; Coli et al , 1998; Gavilanes et al , 2000) and HHF35 (Sugimoto et al , 1993). Ductal cells in normal salivary glands have SDH activity and stain positively for CKs (Tremblay and Pearse, 1959).…”

“…Carlsöö et al (1979) proposed as a diagnostic standard for oncocytoma that mitochondria occupy 60% of the total area of the cytoplasm. Other ultrastructural features of malignant oncocytic cells have been reported including microvilli (Tatemoto et al , 1987), desmosomes (Jalisi, 1968; Gavilanes et al , 2000), lipid droplets, lysosomes (Sugimoto et al , 1993) and chromatin accumulation in the nuclei (Gavilanes et al , 2000). In the present case, the tumor cells had spherical swollen mitochondria with frequently broken cristae that could be found evenly dispersed over more than 60% of the total area of the cytoplasm.…”

“…Only four cases of malignant oncocytoma have been reported in the minor salivary glands (Briggs and Evans, 1967; Goode and Corio, 1988; Ruby and Kish, 1996; Gavilanes et al , 2000), while 51 cases of OC have been reported in the major gland (Coli et al , 1998). Here we report for the first time a pedunculated OC in the buccal mucosa, along with an immunohistochemical and ultrastructural description of the tumor.…”