Primary malignant melanoma of the vagina: A case report of a rare disease that is difficult to diagnose

Rationale: Malignant melanoma is a rare cancer that accounts for approximately 1% of all cancers. Primary malignant melanoma of the female genital tract accounts for approximately 3% to 7% of all malignant melanomas, and 0.3% to 0.8% of all melanomas in women. It affects postmenopausal women ages 60 to 80 years. Various hormonal factors, including puberty, pregnancy, menopause, oral contraceptive use, and human papillomavirus infection are associated with primary malignant melanoma of the vagina. Patient concerns: Symptoms often include vaginal bleeding, discharge, and pain; however, it can also present as pigmented or nonpigmented lesions, making diagnosis challenging. Diagnoses: Diagnosis involves detailed history, physical examination, and imaging (CT, MRI, and positron emission tomography). Immunohistochemical staining for markers, such as human melanoma black-45 and Melan-A, is crucial for confirmation. The diagnosis was made through careful physical examination, imaging studies, and immunohistochemistry. Interventions: The treatment includes wide local excision, radical surgery, radiotherapy, chemotherapy, and immunotherapy. The prognosis of primary malignant melanoma of the vagina is usually poor owing to late diagnosis, and the 5-year survival rate is 5% to 25%. Outcomes and lessons: To consider the possibility of primary malignant melanoma of vagina, postmenopausal women, particularly those who with human papillomavirus infection, should be performed thorough examination regardless of symptoms of vaginal bleeding or discharge.