Ecchordosis physaliphora

Case contributed by Frank Gaillard

Selected images from digitized printed film demonstrate a small high T2 lesion in the rostral clivus with minor enhancement. The patient was asymptomatic, but went on to have surgery. Preoperative differential was between a chordoma and ecchordosis physaliphora



Sections show a fragments of tissue in which there is a diffuse sheeted arrangement of epithelioid cells. These have small hyperchromatic nuclei, a large amount of cytoplasm containing
myxoid/mucinous material and well-defined cell borders and are set within a myxoid stroma.  No well formed cords or solid aggregates of these cells are seen. There are no mitoses and no necrosis is identified.  There is a background inflammatory cell component comprising CD3 positive T cells, CD20 positive B cells and CD68 positive macrophages and neutrophils. Fragments of mature lamellar bone are present with no bone destruction identified.

Immunohistochemistry shows the epithelioid cells to be CAM 5.2+, EMA+, S100 focal +

Double-labeling immunohistochemistry shows positive staining for topoisomerase in a moderate number of the background inflammatory cells. Only scattered lesional epithelioid cells show nuclear staining (proliferation index approximately 1%).

DIAGNOSIS: The histological and immunohistochemical features are those of a
notochordal lesion favoring ecchordosis physaliphora. However, chordoma cannot be absolutely excluded and close patient follow-up is recommended.

Case Discussion

The hardest thing about ecchordosis physaliphora is remembering how to say and spell them. Other than that, they are hard to distinguish from chordomas. Small, indolent, asymptomatic, non-enhancing are the best clues. 

In some ways it is best to not biopsy them as the histology is also difficult to distinguish from the more aggressive chordoma. 

The patient has been followed up for over 5 years and remains well. 

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