A 65-year-old male patient noticed a mass about 2 cm in diameter in the right axillary region in 2008. He consulted a local dermatologist and the mass was diagnosed as benign. In May 2010, after follow-up of 2 years, the mass began to enlarge at a discernible rate, with the presence of tenderness. There was no history of fever, cough, weight loss, decreased appetite, altered bowel habits, melena, or rectal bleeding. He was transferred to the surgical department of an academic medical center for further treatment. At the initial visit, physical examination revealed an elastic hard, nonmobile mass measuring 5.5 cm, with tenderness to palpation in the right axilla. Part of the skin covering the mass was reddish. There was no significant enlargement of other superficial lymph nodes. Both breasts were normal on palpation. Physical examination was otherwise unremarkable.