Important malignant and new nail tumors.

The nail apparatus is an integral part of the functional unit of the digital tip. Although overall uncommon, all cells and tissues occurring in this area can give rise to neoplastic lesions. Given the special anatomical location, such tumors frequently show morphological and symptom-related differences compared to similar lesions located elsewhere on the skin. Though particularly threatening, there is often a substantial delay in the diagnosis of Bowen's disease, ungual squamous cell carcinoma, and melanoma. Nevertheless, local excision with sufficient surgical margins is usually sufficient and superior to amputation of the distal phalanx. In recent years, a number of nail-specific tumors have been described. Tumors such as onychomatricoma, onychocytic matricoma, onychocytic carcinoma, and onychopapilloma originate from the nail matrix. Onycholemmal cysts, onycholemmal horn, and the proliferating onycholemmal tumor are characteristic nail bed tumors. Onycholemmal carcinoma is a slowly growing low-grade malignancy. Using modern diagnostic methods, careful examination - including biopsy and histopathology - of nail changes not responding to conservative treatment will help identify nail-specific neoplasms and prevent the progression of malignant nail tumors