The biopsy specimen revealed a sharply demarcated, deeply basophilic-staining tumor mass in the upper dermis. The nodule had a surrounding fibrous capsule and was not connected to the overlying epidermis. The tumor was arranged in cords and sheets with a glandlike formation and was noted to be composed of 2 types of cells: (1) small, dark basaloid cells with compact nuclei at the periphery, and (2) larger cells with pale nuclei at the center. The findings were most consistent with a diagnosis of eccrine spiradenoma.
Papular Lesion of the Proximal Nail Fold—Diagnosis. Arch Dermatol. 2004;140(8):1003-1008. doi:10.1001/archderm.140.8.1003-b