Malignant melanoma is an unusual neoplasm affecting salivary tissue. The majority of salivary melanomas have been reported to occur as a result of metastatic lesions from cutaneous primary sites, often in the head and neck. Evidence suggesting salivary tissue as a primary site for malignant melanoma is sparse and not definitive, as these salivary neoplasms may result from occult primary extra-glandular locations. Further, metastasis from cutaneous lesions have been demonstrated following what was felt to be curative treatment of the initial primary site, leading to speculation that all salivary melanomas occur as a result of metastasis.
We report a patient with a progressively enlarging submandibular gland mass which ultimately proved to be malignant melanoma, and in whom an active primary cutaneous (or mucosal) site could not be clinically or radiographically established, despite a remote history of curatively treated melanoma in situ. This patient underwent gland removal with concurrent selective neck dissection, the pathologic findings of which demonstrated the presence of intra-glandular melanoma without involvement of any regional nodal tissue. The histopathologic findings and clinical scenario suggest that disease developed within the submandibular gland, and not through metastasis from an extra-glandular site; an example of which has not been previously described.
This presentation focuses on details of the management of this unique patient, particularly in regard to the efficacy of fine needle biopsy assisted cytopathology in securing the diagnosis, together with the implementation of appropriate multimodality treatment. A literature review assists in describing the unusual aspect of suspected primary melanoma affecting salivary tissue without demonstrable extra-glandular primary sites.