Case 106 - Discussion

Uploaded: 2007-09-29, Updated: 2007-09-29

 

 

CD99 S100
SMA Vimentin
   

Microscopic Description (WJH)
Examination of the specimen shows a 1.9 cm, well-encapsulated intramuscular mass. The tumor consists of nodules of spindle-shaped tumor cells with an overall intersecting, fascicular pattern. The tumor shows enlarged nuclei with prominent macronucleoli. The mitotic count is low, approximately 1-2 per HPF. There are no areas of necrosis, hemorrhage or lymphovascular invasion. The tumor cells demonstrate a positive immunohistochemical staining for pancytokeratin (focal), S100, vimentin, and CD99. The tumor cells are negative for melanosome, desmin, SMA, CD34, and EMA.

ELECTRON MICROSCOPY
The tumor is composed of spindle-shaped cells with long, thin intertwining processes. There is extensive basal lamina covering cell bodies. The nuclear to cytoplasmic ratio is high, with pleomorphic roughly oval- to spindle-shaped nuclei with indentations. Most nuclei are euchromatinic with single, large nucleoli. The cytoplasm contains a moderate amount of mitochondria and rough endoplasmic reticulum. Definite long-spacing collagen is not seen. Rare secondary lysosomes are present. (WJH and SR)

CYTOGENETICS REPORT
Normal male chromosome complement: 46,XY[17]
Cytogenetic analysis did not reveal any evidence of a consistent detectable numerical or structural chromosomal anomaly at this band level.
 

  Malignant peripheral nerve sheath tumor
CLINICAL FEATURES
   
GROSS FINDINGS
   
MICROSCOPIC FINDINGS
   
SUBTYPES
   
DIFFERENTIAL DIAGNOSES
   
IMMUNOHISTOCHEMISTRY AND SPECIAL STAINS
   
ELECTRON MICROSCOPIC FINDINGS
   
CYTOGENETIC STUDIES
   
TREATMENT AND PROGNOSIS
   
REFERENCES