Management of primary anorectal mucosal melanoma during the COVID-19 pandemic

Abstract

Anorectal melanoma is a rare and difficult-to-diagnose highly malignant cancer with a poor prognosis. The treatment usually involves surgery and often includes adjuvants such as radiation therapy and immunotherapy. We present a case of a 77-year-old Peruvian who was eventually diagnosed with this cancer during the COVID-19 pandemic, which complicated her treatment and allowed the cancer to spread. Her treatment included abdominoperineal resection, bilateral pelvic lymphadenectomy, left internal iliac vein raffia and end colostomy, followed by 3D radiation therapy (50 Gy, 25 sessions) and systemic treatment with nivolumab, all of which were well tolerated. The patient was alive as of 20 August 2023, having survived for more than 3 years since the onset of symptoms.

Keywords: COVID-19; Peru; anorectal melanoma; nivolumab; radiation therapy; radiotherapy; surgery.

Figure 1.. Micrograph of the unstained tumour. Micrograph (40×) of the tumour excised during surgery; the brown colouration of some cells reveals the presence of melanin, suggesting melanoma.

Figure 2.. Micrograph of the tumour stained with haematoxylin-eosin. Micrograph (40×) of the tumour excised during surgery with haematoxylin-eosin stain. The anorectal mucosa is infiltrated by malignant epithelioid neoplastic cells with prominent nucleoli and melanin.

Figure 3.. RT planning target volume. Planning target volume of the postoperative patient is outlined in orange. The large image is along the transverse plane, whereas the top and bottom images are of the sagittal and coronal planes, respectively.

Figure 4.. Radiation planning dose. 3D pelvic cavity RT planning in the postoperative patient at a dose of 50 Gy in 25 fractions. This transverse image presents the dose distribution to the pelvic cavity.