The surface epithelium was irregularly acanthotic, with extensive proliferation of atypical melanocytic cells at the dermoepidermal junction, and there were foci of junctional nest formation. Also, nests of elongated, spindle-shaped melanocytic cells extended from the dermoepidermal junction to the reticular dermis. Immunohistochemical studies revealed strong S100 protein expression of the tumor cells.
The patient was treated with amputation at the proximal interphalangeal joint of the thumb and has been without recurrence or metastasis during 1 year of follow-up.
Erythematous Nodule on the Nail Bed. Arch Dermatol. 1999;135(9):1113-a-1118. doi:10-1001/pubs.Arch Dermatol.-ISSN-0003-987x-135-9-dof0999