A case of cellular myxoid neurothekeoma with unusual clinicopathologic features.

Cellular neurothekeoma is a benign cutaneous soft tissue neoplasm that usually arises in the upper parts of the body and affects mainly young individuals with a female predominance. This type of tumor shows a spectrum of atypical or "unusual" pathologic features that challenge pathologists in making a correct diagnosis. Herein, we present a case of cellular neurothekeoma with prominent myxoid features and dense interstitial chronic inflammatory cell infiltrate arising in a 28-year-old female as a nodule in the left popliteal fossa. Following a thorough literature search, this case is considered to be the first report of a cellular neurothekeoma arising in the popliteal fossa. The data presented in this case expand our knowledge of the diverse anatomical distributions and wide pathologic spectrum of cellular neurothekeomas.