Neoplastic involvement of terminal digits masquerading clinically as benign disease.

Two patients with primary and four with metastatic distal phalangeal lesions in whom a wrong diagnosis of benign disease was initially made are presented with a brief review of the literature and a discussion of the clinico-radiographic features. Primary phalangeal lesions may be either epidermoid carcinoma or malignant melanoma are are often confused with paronychia, while most metastatic lesions are due to pulmonary or breast cancer and simulate a felon clinically. Primary nail bed lesions are characterized radiographically by external cortical erosions; metastatic lesions tend to show a diffuse demineralization and extensive destruction of the whole digit.