Primary malignant melanomas of the female lower genital tract: clinicopathological characteristics and management

Abstract

The female lower genital tract melanomas mainly include vulvar, vaginal and cervical melanoma. There is little clinical data on the melanomas thus making them highly lethal with their prognosis being worse than for cutaneous melanoma and other gynecological malignancies. Surgery is still the primary treatment for gynecological melanomas with wide local resection (WLE) of tumors with adequate margins being preferred for early-stage vulvar melanoma while complete resection of the primary tumor is the standard treatment for early-stage cervical and vaginal melanoma. Sentinel lymph node biopsy seems to avoid unnecessary complete regional lymphadenectomy. However, it should be chosen cautiously. Recently discovered molecular changes have provided new hopes for effective systemic treatment of female genital tract melanomas. In this review, we summarize the pathogenesis and clinicopathological characteristics of these rare melanomas with particular emphasis on new therapies and clinical management methods that may affect prognosis. The review aims to provide a viable direction for clinicians to diagnose and treat female lower genital tract melanomas.

Keywords: Vulva; cervix; diagnosis; malignant melanoma; prognosis; target therapy; vagina.

Figure 1

Two digital pictures of the gross specimens of cervical melanoma. The first patient was a 54-year-old postmenopausal woman, and the lesions had infiltrated the full thickness of the cervix and vagina. Because vaginal malignant melanoma often occurs in the anterior wall of the distal end of the vagina, this patient was diagnosed with primary malignant melanoma of the cervix infiltrating the vagina (A). The second patient was 75 years old, and a cauliflower-like mass could be seen on the cervix, approximately 2 cm in size. Also, there is a small black mass at the external cervix (B).

Figure 2

Schematic representation of normal female lower genital tract and mucosal melanoma tissue structure. The drawing shows the normal anatomy of the female genital tract, including the vulva, vagina, and cervix. The pullout shows a close-up view of the squamous cell and basal cell layers of the cervix. Melanocytes can be seen in the normal squamous cells which form the origin of melanoma. The basement membrane is between the epidermis and dermis. Melanin is shown in the cells.

Figure 3

Pathological characteristics of cervical malignant melanoma. (A) Spindle tumor cells and melanin granules are visible in the cytoplasm (A1, H&E staining, 100×). The tumor cell morphology is irregular and mainly polygonal. The nucleoli are enlarged, with abundant acidophil cytoplasm. Melanin granules are visible in some cytoplasm (A2 & A3, H&E staining, 200× & 400×). (B) The tumor cells were positive for S-100 (B1, 200×), Melan-A (B2, 200×) and HMB 45 (B3, 200×).

Figure 4

Schematic diagram of vulvar melanoma management. The revised AJCC 2017 melanoma staging system based on the current information on vulvar cancer and standard treatment of cutaneous melanoma is recommended for vulvar melanoma. WLE = wide local excision. SLNB = sentinel lymph node biopsy.

Figure 5

Schematic diagram showing the management strategies for vaginal melanoma. The revised AJCC 2017 melanoma staging system is based on the current information on vaginal cancer and standard treatment of mucosal melanoma. WLE = wide local excision. SLNB = sentinel lymph node biopsy.

Figure 6

Schematic diagram of cervical melanoma management. The FIGO staging system is recommended for cervical melanoma, based on the current information on cervical cancer. WLE = wide local excision. SLNB = sentinel lymph node biopsy.