Merkel cell carcinoma--a problem with microscopically controlled surgery.

Trabecular cell carcinoma, originally described by Toker, is a malignant skin tumor, probably of Merkel cell origin. These tumors are locally aggressive and may metastasize. Prompt surgical removal is mandatory. The clinical features are often not diagnostic, and diagnosis is primarily by histologic examination. Special studies, especially electron microscopy, may be required to differentiate this tumor from others. During surgery, particularly with Mohs microscopically controlled excision, provision must be made for proper handling of the specimen so that these special studies can be carried out.