[Osteoclast-type giant cell tumor of the parotid gland]

Osteoclast-type giant cell tumors of the salivary gland are extremely rare; only 23 cases have been reported. Two presentations were observed: isolated tumor or tumor associated with a carcinomatous contingent.

A 51-year-old female patient consulted for a painless left retro-angulo-mandibular swelling having appeared 2 years before. This was a 2 cm parotid mass without facial nerve palsy or cervical lymphadenopathy. The patient underwent a superficial parotidectomy to remove the nodule. The direct microscopic examination revealed an osteoclastic giant cell tumor without any carcinomatous contingent. At immunohistochemistry, mononuclear cells were diffusely and intensely stained by anti-pancytokeratin, while multinucleated cells were totally negative and CD68 positive. The patient was not given any complementary treatment. She was followed-up 23 months later and did not present any signs of recurrence or metastasis.

The histogenesis and nosology of osteoclastic giant cell are currently unknown. Although this entity was not integrated into the latest WHO classification, most authors consider it as a variant of carcinoma. Published data on the epithelial or histiocytic nature of multinucleated cells is not consensual. Our case presentation supports the hypothesis of a histiocytic differentiation of giant cells and epithelial mononuclear cells.