Skin tumors may imitate infectious processes.

A small nodule on the middle finger of the right hand of a right-handed dentist was removed and found to be benign. The lesion recurred and showed increased collagen deposition and vascularity; it was diagnosed as a dermatofibroma. In the absence of a specific incidence of trauma, the cause of such a lesion is a matter of speculation. Such lesions can develop as local tissue reactions to wounds that are the result of routine operatory procedures. This points to the need for careful handling of sharp instruments. Because of the serious consequences of a malignancy or infection from HIV, nodules and other lesions of unknown etiology that appear suddenly should not be ignored.