Subungual Exostosis

It starts up with development of tumors of the bone or an outgrowth of bone from the upper most portion of the toe or finger. It is called subungual because it happens below the nail arising on the distal phalanx. It’s very first case was of involving the thumb in a six and half year old-female child. Its cause is still unknown till now. It is necessary to perform X-rays of the lesion to know its bony origin.

It is rare case of Osteochondromas which are bone plasms & they are the commonly found tumors of the toe of foot. The growth of tumor is seen in the last part of tiny bones, known as the tip of the toe. Though it can not be noticed so easily but when treated gives a lot of pain to the patient.

It is defined Exostosis Cartilaginea due to its distinctive variety cartilaginous cap like the tumor emerges from the nails plate. It is type of a lesion which is mostly asymptomatic but sometimes can pain & ulceration of the bed of nail could occur. It normally develops during teenage & less common in males than females. Subungual exostosis cases are very minute under the age of nine years. Some factors which have been told for this exostosis are trauma, chronic infection or sometimes a genetic disorder. Etiology had also declared as congenital, but trauma looks to be commonly reported news in the famous subungual type tumor.

It can transform into a chondrosarcoma. Its transformation from benign tumor to malignant tumor had also been found, but not subungual Osteochondromas. It can be removed by surgical treatment. The lesions grow outwards up throughout the nail bed and look as strong, marble like lobulated or sometimes little translucent. As per, it’s diagnosis is mostly is made on radiographs. On radiographs, subungual exotosis appears as bony outgrowth growing from the parent bone of the toe or finger. The growth has clear cortical margins without any destruction of the parent bone. The growth of cortex and medulla are continuous with the parent bone. It’s cap is not seen as it is radiolucen and can be viewed on histopathology. By the histopathological reports, subungual exotosis resembles an osseous callus in its shape and gradations to bony trabeculae (a base of trabecular bone is lined by a cartilage cap with some ossification starting from base to cap).

Treatment options can have curettage of the lesion, allogenic bone graft, ablation and the use of cauterization. Differential checkup includes osteochondroma, enchondroma, and other malignant tumor of some cartilaginous origin or chondroblastoma. The cartilaginous part of the tumor was destroyed and reduced down to raw bone. A very high speed rotary burr was then employed to saucerize and remove the remaining bone. A curette named tool was then employed to remove any loose bone from the base of any injury or any defect. After some days of removal of the tumor, healing of the nail bed is observed. After some days of surgery nail bed re-growth takes place.