UPMC Case:

-- 59-year-old man, left chest wall/axilla mass, with history of chest wall  tumor,  US-guided FNA was performed.

 The final diagnosis is parachordoma.

Parachordoma:

-- rare soft-tissue tumor resembling extraskeletal myxoid chondrosarcoma and chordoma

-- age from 7 to 62 years (mean, 35 years)

-- Sites: subfascial masses of the thigh, arm, chest wall, and buttocks 

-- Histopath: large, rounded eosinophilic cells embedded in a matrix that varied from myxoid to densely hyaline and multivacuolated (physaliferouslike)

 cells

-- Special stains: matrix stained with Alcian blue (ph2.0)

-- IHC: 

* strongly expressed CK 8/18, but not the others 

* also positive for: expressed EMA, S-100, and vimentin

-- D/Dx: 

* chordoma --> Positive for CK 8/18 (15 of 15) and CK 1/10

* extraskeletal myxoid chondrosarcoma --> consistently lacked CK

强子, thanks for your help. 

 Additional informtion of Case 1:
The immunohistochemical studies show the neoplastic cells are positive for EMA, S-100, Vimentin, CK8/18 but negative for CK19.

What is the most possible diagnosis (please think out side the box)?