A Rare Case of Cutaneous Metastasis of Unresectable Rectal Adenocarcinoma

Colorectal cancer (CRC) is the third most common malignancy. Common metastatic sites for colorectal carcinoma are the lung and liver while cutaneous metastases are extremely rare. Skin metastasis may be an early manifestation of metastatic disease and represents a poor prognosis. Here we present a case of metachronous skin metastasis during chemoradiation treatment in a patient with locally advanced rectal cancer. A young boy aged 19 years presented to our hospital with radiological TNM staging of T3c N1 M0 with circumferential resection margin (CRM) involved. The treatment plan was defunctioning colostomy with neoadjuvant chemotherapy and radiotherapy with a later plan for surgery. Seven months later, there is a focal skin nodule in the nape of the neck. A core biopsy of this cutaneous nodule was done and proved metastatic. Surgery for the primary tumor and oligometastatic site was planned but due to extensive primary tumor, surgery was terminated and continues with chemotherapy and reassessment.