​Dermatology - Anogenital Region Malignant Melanoma

​Dermatology - Anogenital Region Malignant Melanoma
Although malignant melanoma of the anogenital region is uncommon, the prognosis is unfavorable due to early metastasis through lymphatic veins. Moreover, due to the lack of regular examination of the anogenital region for precancerous and cancerous abnormalities, the diagnosis is frequently delayed until the disease has progressed significantly.
The presence of macules or papules displaying a mixture of brown-black color, uneven boundaries, and frequently accompanied by raised papular elevation or ulceration. In males, lesions are predominantly found on the glans (67%), prepuce (13%), urethral meatus (10%), penile shaft (7%), and coronal sulcus (3%). In females, lesions are primarily seen on the labia minora and clitoris.


The diagnosis is established through clinical examination and further validated by doing a biopsy of the affected area. Complete excisional biopsy with limited margins is the most favorable approach, while incisional or punch biopsy is acceptable in cases where complete excisional biopsy is not feasible. Avoid utilizing shave biopsy since it does not accurately indicate the extent of invasion. The possible causes for the condition are genital lentiginosis, old fixed drug eruption, squamous cell carcinoma (SCC), hemangioma, and intraepithelial neoplasia (Bowenoid papulosis).

The treatment involves the complete removal of tissue down to the fascia. When dealing with lesions that are less than 1 mm thick, it is important to have margins of 1 cm from the edges of the lesion. Biopsy of lymph nodes should only be done if the nodes can be felt. For lesions that are larger than 1 mm in thickness, it is important to have a margin of 2 cm and do a biopsy of the sentinel lymph nodes. Proceed with excision followed by immediate closure or repair using skin grafts. Perform lymphadenectomy exclusively for nodal basins exhibiting occult tumor cells or in cases where nodes are clinically palpable and display suspicious characteristics indicative of tumor presence. Adjuvant therapy should be considered in cases where there is a danger of recurrence, such as when there are positive regional lymph nodes or the cancer is in an advanced stage.