Histopathologic aspects of cutaneous metastatic disease.

In cutaneous metastatic disease the histologic pattern may be specific or nonspecific. Carcinoma cutis most often shows only the nonspecific pattern of an adenocarcinoma, a squamous cell carcinoma, or an undifferentiated metastatic tumor. However, certain clinical and histologic characteristics may suggest a primary tumor site and type. In addition, special histologic stains and the use of immunohistochemical and electronmicroscopic techniques may also prove valuable in the diagnosis of carcinoma cutis and other cutaneous metastatic diseases.