Mixed Tumor of the Skin: Clinicopathological Study of Seven Cases

ABSTRACT

BACKGROUND: Mixed tumor of the skin or chondroid syringoma is a benign neoplasm characterized by histological features of a mixture of epithelial and mesenchymal components. It is a rare and benign appendageal tumor, found mostly on the head and neck, and present as an asymptomatic, firm, subcutaneous nodule. There have only been a few reported cases in Korea. OBJECTIVES: This study was aimed to characterize the clinical and histopathlological features of mixed tumor of the skin. METHODS: We reviewed the clinical data and histologic slides of seven patients who have been diagnosed with mixed tumor of the skin by histopathological examination. RESULTS: There were six male patients and only one female. Age of onset of mixed tumor of the skin varied from 26 to 65 years. A11 patients had the lesion on the head perioral area (3 cases), nose (2 cases), cheek (1 case), and temple area (1 case). Each tumor was a solitary, asymptomatic, and firm, about 0.5-1.5 cm sized, subcutaneous nodule. Histopathologically, all 7 cases presented apocrine differentiation. Two cases showed follicular differentiation, and 2 cases showed sebaceous differentiation. Every tumor showed myxoid stroma except two with typical chondroid matrix. Adipose metaplasia of the matrix was present in 2 cases. In 3 cases, the so-called hyaline cells were rich in the stroma. CONCLUSION: Mixed tumor of the skin was most commonly seen as an asymptomatic, firm subcutaneous nodule on the head. Tumors showing apocrine differentiation were more common than that of eccrine differentiation, All 7 cases presented apocrine differentiation. Follicular and sebaceous differentiation might occur in apocrine type of mixed tumors of the skin. The stroma of mixed tumor of the skin might be myxoid, chondroid, or adipose.