Subungual Calcification and Nail Dystrophy: A Case of a Man With Subungual Calcinosis Cutis and an Associated Split Nail Plate.

A dystrophic nail is an alteration of the physical appearance and structural properties of the nail from its shape, color, and texture, which can result from multiple etiologies. Calcinosis cutis is a condition that refers to the calcium deposition in the skin and underlying tissue. A 55-year-old man who presented with a split right thumbnail associated with subungual calcinosis cutis affecting the same digit for a duration of nine years is described. He did not recall trauma to the affected area. Microscopic evaluation of the tissue specimen obtained following a biopsy of the affected digit's nail matrix showed foci of calcium in the dermis. The correlation of his clinical presentation and biopsy findings established a diagnosis of subungual calcinosis cutis. Subungual calcification has been observed in several clinical settings. In addition to subungual calcinosis cutis, it has been noted as a normal finding in elderly individuals. In addition, it has been observed in patients with scleroderma or following trauma to the site. Less commonly, subungual calcification can be associated with idiopathic conditions: calcifying aponeurotic fibroma, digital calcinosis circumscripta, subepidermal calcified nodule, and calcified subungual epidermoid inclusion.