Recurrent Vulvar Melanoma – a Case Report

Abstract

Abstract Melanoma rarely develops in the genital area. It is responsible for 5% of all vulvar malignancies. Postmenopausal women are usually more affected and the main differential diagnosis is vulvar melanosis and vulvar nevi. There are limited numbers of studies on dermoscopic features of mucosal melanoma, particularly early-stage lesions. Dermoscopic criteria have been described for the diagnosis of vulvar melanosis, and observational studies have been conducted to define the dermoscopic features of nevi and melanoma on the vulva. We are presenting the case of a 69-year old female with suspected recurrence of vulvar melanoma who previously had surgical removal of mucosal lentiginous melanoma on the left labia minor in June 2017. Five months after the primary melanoma surgery, the patient noticed de novo pigmentation at the left and right labia minor and urethral opening. On clinical examination, irregular light-brown pigmentation with ill-defined borders was evident on the labia minora of the vulva and around the external urethral orifice. On dermoscopy, irregular pigmented network, with white scar-like and structureless pinkish areas was evident. Incisional biopsy of the vulvar mucosa revealed melanoma in situ, confirming the local recurrence. CT scans of the head, thorax, abdomen and pelvis and gynaecological examination revealed no secondary deposits. Ultrasound of the regional inguinal lymph nodes revealed enlarged suspected pathologic involvement of the lymph nodes in both inguinal regions. Lymph node fine needle aspiration of lymph nodes in the left and right inguinal area revealed pleomorphic infiltrate of lymphoid cells with hemosiderin or melanoma pigment in the cytoplasm. Cystoscopic findings were within normal range. Interdisciplinary tumour board indicated wide excision of melanoma with margins of 1 cm and resection of the urethra, as well as biopsy of the enlarged left inguinal lymph node. Histopathological analysis of the resected mucosa revealed lentiginous spread of melanocytes showing moderate atypia, with focal pagetoid spread, without mitoses and ulceration and without invasion of lamina propria. The resection margins were tumour-free. Non-specific lymphadenitis was diagnosed on lymph node histopathological analysis. The patient was regularly monitored by a dermatologist and urologist, and had no recurrence. The accurate and prompt diagnosis is essential in the case of the vulvar melanoma which has unfavourable and unpredictable prognosis, with a tendency of local recurrences and regional and distant metastases in the case of invasive melanoma. In order not to miss early mucosal melanoma, dermatologists and gynaecologists should not avoid biopsy of lesions that demonstrate any clinical or dermoscopic feature of atypical melanocytic lesion, especially in case of the development of irregular pigmentation that expands and changes over time, the appearance of a solitary amelanotic papule or nodule requires excision or, in case of large diameter lesions, incision biopsies. Larger studies are needed to define more rigorously clinical and dermoscopic criteria that accurately distinguish early mucosal melanomas from benign skin lesions.