Skin metastases from visceral cancers are rare and the reported incidence from all visceral cancers is 1.4% to 10%. Skin metastases from colorectal cancers account for only 5% of metastatic skin cancers, among which scalp metastases are very rare. We describe a 53-year-old man with scalp metastasis derived from sigmoid colon cancer that was diagnosed and surgically resected in 2005. Metastatic lung tumors that developed thereafter were surgically resected and then chemotherapy was administered. However, metastatic brain tumors occurred in 2008, and these were treated by c-knife radiosurgery. Around the same time, a raised lesion that appeared on the scalp was diagnosed as skin metastasis and treated with best supportive care. Thereafter, the brain metastases continued to spread, and the patient died in October 2008.Key words: Skin metastasis -Colon cancer -Scalp metastasis -Brain tumor S kin metastases arising from gastrointestinal cancer are rare, and the theoretical incidence of skin metastases in colorectal cancers is less than 5%.1,2 This case report describes scalp metastasis that developed after surgery for sigmoid colon cancer.
Case ReportColonoscopy for a detailed examination of melena revealed sigmoid colon cancer in a 53-year-old man in December 2005 (Fig. 1). Preoperative blood tests revealed carcinoembryonic antigen and cancer antigen 19-9 levels of 6.7 ng/ml and 27.1 U/ml, respectively. Sigmoidectomy was performed in January 2006, and the pathologic diagnosis was well-differentiated adenocarcinoma, lymphovascular invasion (+), T3, N0, M0, stage II. Chest computed tomography (CT) and positron emission tomography imaging in September 2006 revealed an isolated lesion, 6 mm in diameter in the right lung. A metastatic lung tumor was diagnosed (Fig. 2), and in December of the same year the patient underwent thoracoscopic partial resection of the target area in the right lung. The pathologic diagnosis was metastasis from colorectal cancer. The patient received systemic chemotherapy after surgery. However, chest CT images detected tumors in the (Fig. 2), but images obtained in November of the same year revealed recurrence of this tumor and destruction of the right fifth rib. The tumor beds were irradiated with 20 Gy of X-rays to relieve pain and systemic chemotherapy was administered. In April 2008, brain metastases in the left and right frontal lobes were treated by c-knife radiosurgery with target doses of 22 Gy each (Fig. 3). A red, sessile, elastic, firm, raised lesion, 19 mm in diameter, with a glossy surface on the skin of the median area of the occipital region (Fig. 4) was confirmed as skin metastasis of the scalp. This was treated symptomatically. Thereafter, the brain metastases continued to spread, and the patient died in October 2008.
DiscussionMetastatic skin cancer is defined as skin metastases from visceral cancer, excluding primary skin cancer and hematologic malignancies. Skin metastases derived from visceral cancers are rare and the reported incidence ranges from 1.4% to 10% of all viscer...
