Table 1.

Overview of immunohistochemistry and molecular findings at different pathology institutes

	Local pathology	Tertiary referral center	US institution	German institution
Diagnosis	−	MBC	central type of PNET	EFT
CD99	positive	positive	positive	positive
Vimentin	positive	positive	−	positive
Cytokeratin 7, cytokeratin 20	positive	−	−	−
Cytokeratin AE1/AE3	positive	positive	positive	positive
Synaptophysin	−	−	positive	positive
CD56	−	−	positive	−
Chromogranin A	negative	−	−	positive (single cells)
WT1	negative	−	−	negative
CA15-3, TTF1, β-hCG, CD10	negative	−	−	−
Estrogen, progesterone receptors	negative	negative	−	−
S-100	−	−	negative	negative
Desmin	−	−	negative	negative
GFAP	−	−	negative	−
CK5/14, smooth muscle actin, myogenin, 34βΕ12,
MPO, CD20, CD3	−	−	−	negative
t(11;22)	−	negative	−	negative
t(21;22)	−	negative	−	negative
t(18;X), i(12)p	−	negative	−	−

EFT, Ewing family tumors; MBC, metaplastic breast cancer; PNET, primitive neuroectodermal tumor.