Nodular melanosis due to epithelial neoplasms: a finding not restricted to regressed melanomas.

Nodular or tumoral melanosis consists of nodular or sheetlike deposits of melanophages in the dermis. When nodular melanosis is present, a completely regressed malignant melanoma is a major diagnostic consideration. We present a case of nodular melanosis due to regression of a pigmented basal cell carcinoma with pilar differentiation. In addition to this case, we present five additional cases of epithelial neoplasms with melanin deposition in the stroma. In each case, the source of the melanin was non-neoplastic dendritic melanocytes intermingled among the tumor cells. Therefore, if nodular melanosis is found, pigmented epithelial neoplasms should also be considered in the differential diagnosis.