Primary malignant melanoma at unusual sites: an institutional experience with review of literature.

Apart from the skin and choroid plexus, primary malignant melanoma is rare at the other sites and lacks organized documentation. Here, we have tried to enumerate the primary malignant melanomas at various atypical sites, supported by literature review. Seventeen cases were identified from our records of the past 5 years, which had detailed clinical work-up to exclude a possibility of a metastasis. A clear female predominance with involvement of the lower genitourinary tract was identified. In addition to three cases from the vagina, two cases each from the cervix, ovary and urethra, respectively, such cases were also identified in cerebral cortex (frontal and fronto-parietal area), rectum, nasal cavity, tongue, breast and tonsillar fossa. Although many were amelanotic, no specific histology was noted. In conclusion, malignant melanomas can arise in unconventional areas. Gross tumor appearance and the unavailability of an immunohistochemical panel, may result in their misdiagnosis as primary epithelial malignancies. A possible metastasis should always be ruled out.