Malignant chondroid syringoma.

A case of malignant chondroid syringoma on a foot with multiple bone metastases is presented. An 18-year-old male patient first noticed a protruding mass on the plantar surface of his right foot at 9 years of age. A sweat gland tumor of a benign nature was diagnosed and excised at that time. The tumor recurred three times during the 10 years after surgery and was finally diagnosed as malignant chondroid syringoma. Multiple bone metastases involving the calcaneus, talus and fibula of the lesion side were found after extensive radiologic survey. The patient underwent below-knee amputation with total removal of the fibula. However, pelvic bone metastasis developed 1 year after the amputation. He died of this disease due to brain and diffuse bony metastasis 36 months after the amputation. This is a rare case of malignant chondroid syringoma with a long history but ominous outcome. We recommend that sweat gland tumors be carefully examined and treated more radically when there is a suspicion of malignancy.