Chondrolipoangioma. A cartilage-containing benign mesenchymoma of soft tissue. The clinical and pathologic features of four cases of benign mesenchymoma in which mature cartilage represented the predominant component are reported. The distinctive histologic feature in all four cases was a lobular proliferation of cartilaginous tissue exhibiting a spectrum of hyaline cartilage, fibrocartilage, myxoid cartilage, and cartilage with ossification and even bone marrow formation, intimately associated with mature adipose tissue and vascular elements. The localization of these tumors was in the proximity of a bone, but not attached to the periosteum or in continuity with a joint. Because these lesions may be mistaken for other cartilaginous neoplasms of soft tissue, recognition of this entity has potentially important diagnostic and therapeutic implications in that mutilating surgery may be avoided. 