A Case Report of Locally Advanced Anal Cancer with Solitary Cutaneous Nodular Metastasis in the Ipsilateral Labia Majora Treated with Definitive Chemoradiotherapy

Cutaneous metastasis from anal cancer is rare at the initial diagnosis. There is a dearth of information on definitive treatment for anal cancer with cutaneous metastasis. We report the case of a 63-year-old female with locally advanced anal cancer and solitary cutaneous nodular metastasis in the right labia majora identified at the initial diagnosis that was successfully treated with definitive chemoradiotherapy. She arrived at our hospital with complaints of an enlarging perineal itching nodule. Genital and rectal examination detected an anal tumor with perineal and rectal invasion. The biopsy specimen indicated it was a squamous cell carcinoma that was accompanied by right inguinal and external iliac lymph nodal metastases and solitary cutaneous nodular metastasis in the ipsilateral labia majora. She was diagnosed with anal cancer, clinical T3N1M1, stage IV (UICC-TNM 7th). She had good performance status and effective organ function. She received definitive chemoradiotherapy with irradiation fields that included the primary tumor, pelvic lymph nodal metastases, and solitary cutaneous genital metastasis. After completing the planned treatment, all tumors vanished without recurrences at 42 months after treatment. In conclusion, patients with locally advanced anal cancer may suffer genital cutaneous metastasis that develops with lymphatic drainage from the anus to the inguinal lymph nodes. Anal cancer with solitary genital cutaneous nodular metastasis can be considered as a local-regional disease and can be treated with chemoradiotherapy. Chemoradiotherapy achieved a cure in our case.