ABSTRACT
This chapter describes the several tumors with adipocyte, myxoid, muscular, osseous, and cartilaginous features. It discusses types of tumors, including benign tumors and malignant tumors. The chapter explains the histopathology and differential diagnosis of some of the benign tumors, such as lipoma, myxoma, myxoid pseudocyst, chondroma, osteoma cutis, subungual exostosis, osteochondroma, subungual calcifications, osteoid osteoma and giant cell tumor of the bone. Three types of subungual chondroma have been observed in the tip of digits: enchondroma, parosteal chondroma, and soft tissue. The chapter also explains the histopathology and differential diagnosis of some of the malignant tumors, including leiomyosarcoma and chondrosarcoma. Palpation is rarely helpful in subungual lesions as the nail covers the tumor and does not allow exact determination of its consistency. Immunohistochemistry may be necessary to rule out a myxoid neurogenic tumor or another so-called "ancient" tumor with mucinous stroma degeneration.
