Unusual Case of Solitary Perineal Subcutaneous Metastasis From Sigmoid Colon Cancer

Subcutaneous metastasis from colorectal cancer is an unusual presentation. Most perineal subcutaneous metastases are found in extensive involvements of multiorgan metastases or local recurrences of rectal cancer. Subcutaneous metastasis from colon cancer is considered as a distant metastasis with poor prognosis. We report an unusual case of solitary subcutaneous metastasis beneath the perineum without solid organ involvement after a curative anterior resection for sigmoid colon cancer. The patient underwent a perineal resection, and chemotherapy with the FOLFOX (fluorouracil, leucovorin, and oxaliplatin) regimen was instituted. Eight months later, multiple lung metastases were found, and chemotherapy was restarted with the FOLFIRI (fluorouracil, leucovorin, and irinotecan) regimen. However, lung metastases progressed, and new metastases appeared at the adrenal glands, the kidneys and the cerebellum. The patient died 30 months after the diagnosis of perineal subcutaneous metastasis. He lived relatively long in comparison with patients in previous reports.