Granular Cell Tumor

 Most common nonepithelial tumor of extrahepatic bile ducts






Clinical Issues




• Occur most often in young African American women
image Mean age: 34.7 years

• Most frequent location is common bile duct

• Often discovered incidentally

• Cured by adequate surgical excision
image Excellent prognosis

image Malignant granular cell tumors (GCTs) not reported in biliary tract


Macroscopic




• Often grows concentrically around bile duct, compressing lumen

• Usually < 3 cm in greatest dimension


Microscopic




• Nests or sheets of infiltrating cells
image Cells may be separated by collagenous bands

image Oval to polygonal cells

image Abundant pink granular cytoplasm with small hyperchromatic nuclei

• Can be associated with marked atypia of overlying biliary surface epithelium
image May mimic malignancy

image Important to recognize underlying GCT


Ancillary Tests




• Strong diffuse immunopositivity with S100

image
Concentric Growth Pattern
This granular cell tumor is growing concentrically around the common bile duct, compressing the lumen. The tumor cells can have a very infiltrative growth pattern and may surround small peribiliary glands image .


image
Granular Cytoplasm
The tumor cells have abundant pink granular cytoplasm and small hyperchromatic nuclei.

image
Interspersed Collagen Bands
The granular, pink, polygonal tumor cells are often interspersed with bands of collagen.

image
S100
S100 is strongly and diffusely positive within tumor cells. (Courtesy J. McKenney, MD.)


TERMINOLOGY


Abbreviations




• Granular cell tumor (GCT)


Synonyms




• Granular cell myoblastoma


Definitions




• Benign tumor composed of large, granular, eosinophilic cells
image Immunohistochemistry and electron microscopy have shown schwannian differentiation

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Apr 20, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Granular Cell Tumor

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