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Case 28 - Discussion

Surgical Pathology Case

EM EM
EM EM
EM EM
   
 

Immunostaining:
Vimentin        -       positive
CD56            -       positive
CKAE1/3     -       negative
Desmin         -       negative
SMA            -       negative
CD57           -       negative
S100            -       negative
CD68          -       weak focal positivity

 

Microscopic Description
The tumor is present in the vicinity of several large nerves. It is composed of spindle cells that are arranged in densely packed short fascicles or loosely arranged within fibrous stroma or within myxoid background. Extreme pleomorphism is noted focally and the tumor cells have giant hyperchromatic nuclei. Geographic necrosis is present.

 

Electron Microscopy

Ultrastructurally, the tumor cells are spindle-shaped, some of which show long, intertwining cell processes. There is focal basal lamina formation. The nuclei are pleomorphic with many indentations; generally one large nucleolus is seen within the tumor cells. The nuclear to cytoplasmic ratio is high. the cytoplasm contains abundant rough endoplasmic reticulum, and some mitochondria and lysosomes.

 

Diagnosis:

High grade sarcoma, consistent with malignant peripheral nerve sheath tumor
Histopathologic grade: 3/3 (FNCLCC grading system)