CASE N°01 – Ewing/PNET

Clinical History:

Age: 25

Sex:  male

Pericardial effusion. Thorax TAC:  big mediastinal neoplasia (diameter 14×9 cm.) involving pulmonary veins & pericardial extensions.

 Cytological Images:

Cytological material: FNA mediastinal mass

PAP 100X

PAP 200X

PAP 600X

H/E 200X

H/E 600X

 Cytological Report:

Presence of isolated, rounded, small-medium sized atypical cells. No necrosis, evidence of mitotic activity. Suspicious Small Round Cell Tumor Type.

 Histological Images:

Hystological material: FNAB Lung nodules

H/E 200X                         H/E 200X

CD56 +                              CD99 +

CKPool –                           Synaptofisin –

 Histological Report:

Malignant small cells Neoplasia Compatible with Ewing/PNET. Immunohystochemistry: CD99+, CKpool-, CK34BE12-, p63-, CD5-, S100-, CD56+, Synaptofisin-.

  1. Hello,
    I’m a new guest at your site. And I find it really helpfull and interesting. I’m just learning, preparing to be a veterinary pathologist. Could you tell me why do you find these cells round? For me they are much more fusiform than round…


    • you’re right. it is because this type of tumor is classified under the so called “little blue round tumors”. bytheway a little bit of pleomorphism it is possible and the cells are ovoidal. Another fact that can cause the cells appears fusiform is because of the smearing artifacts. thank you for this.


  2. Is this because of their nuclei? Which are rather round, not oval…


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: