Case 130 - Discussion

Uploaded: 2007-10-26, Updated: 2007-10-26

 

 

   
   
   
 

Microscopic Description (JW, CD)
Microscopic examination shows that the mass is capsulated. The tumor cells have abundant pink, pale blue cytoplasm and oval or spindle nuclei. Some cells have a predominant basophilic nucleolus. There are no nuclear polymorphism and mitosis. Immunohistochemical stains show that the tumor cells are positive for S-100, negative for desmin, SMA, CD117 and CD44. Both the morphology and immunophenotypes support a diagnosis of granular cell tumor.
 

 

Granular Cell Tumor

The Key Features

  • Fine granular eosinophilic or amphophilic cytoplasm;

  • S100+;

  • Cytoplasmic lysosomes under EM.

CLINICAL FEATURES

 
  • 2nd most common stromal tumor of the esophagus, usually in the distal esophagus;

  • M>F, average age 40-50 years;

  • Excellent prognosis

GROSS FINDINGS

 

MICROSCOPIC FINDINGS

 
  • Tumor cells arranged in nests or clusters separated by collagenous fibrous;

  • Granular cells: polyherdral, round, spindle, or epithelioid cells; nuclei, from small/dark to large/vesicular chromatin;

  • Abundant eosinophilic or amphophilic (not bright red as seen in oncocytes) granular cytoplasm, mostly small and regular, occasionally larger round homogenous eosinophilic droplets;

  • Pseudoepitheliomatous hyperplasia of overlying squamous epithelium, may mimic SCC;

  • Close association between granular cells and peripheral nerve;

  • Malignant features: atypical mitosis, necrosis, pleomorphism and ulceration of overlying epithelium. However, mild to moderate atypia do not indicate malignancy.

DIFFERENTIAL DIAGNOSES

 
  • Leiomyoma: bright pink cytoplasm, no granular pattern;

  • Rhabdomyoma: contains cross-striation and glycogen;

  • GIST: no granular cytoplasm, CD117+;

  • SCC: marked acanthosis of overlying epithelium of granular cell tumor may mimic SCC.

IMMUNOHISTOCHEMISTRY AND SPECIAL STAINS

 

ELECTRON MICROSCOPIC FINDINGS

 

TREATMENT AND PROGNOSIS

 
  • Excellent prognosis

REFERENCES

 
  • AFIP Atlas of Tumor Pathology - Fourth Series. Nonmelanocytic Tumors of the skin;

  • Rosai and Ackerman's Surgical Pathology. 9th Edition;

  • Enzinger and Weiss's Soft Tissue Tumors, 4th Edition. By Drs. Sharon Weiss and John Goldblum.

  • http://www.emedicine.com/med/topic2493.htm