Combined Merkel cell carcinoma and atypical fibroxanthoma.
BACKGROUND
Although there are reports of squamous cell carcinoma arising within and adjacent to Merkel cell carcinoma, and one report of an atypical fibroxanthoma-like tumor arising in an irradiated recurrent Merkel cell carcinoma, there have previously been no reports of an immunohistochemically verified atypical fibroxanthoma occurring in conjunction with a Merkel cell carcinoma.


OBJECTIVE
We report on a neoplasm with distinct features of both Merkel cell carcinoma and atypical fibroxanthoma.


METHODS
Histologic and immunohistochemical evaluations were performed.


RESULTS
Our results verify the finding of a combined Merkel cell carcinoma and atypical fibroxanthoma.


CONCLUSIONS
This case is an interesting and unusual combination of tumors. The origin of the Merkel cell carcinoma is revisited. Debated origins include neuroendocrine, epithelial, and pleuripotent stem cell.
Youker
Summer R
SR
Department of Dermatology, St. Louis University, St. Louis, Missouri 63104, USA. sumyou@hotmail.com
Billingsley
Elizabeth M
EM
D000368:Aged; D000369:Aged, 80 and over; D015266:Carcinoma, Merkel Cell / Q000175:diagnosis* / Q000628:therapy; D003937:Diagnosis, Differential; D017809:Fatal Outcome; D051677:Histiocytoma, Malignant Fibrous / Q000175:diagnosis* / Q000628:therapy; D006801:Humans; D007150:Immunohistochemistry; D008048:Lip Neoplasms / Q000175:diagnosis* / Q000628:therapy; D008297:Male