Pathology | Retroperitoneum II - [click on image(s) below]
Neurilemmoma (Schwannoma)
Clinical: by definition, the solitary neurofibroma occurs in patients without neurofibromatosis I (NF-1).; this is the most common type (90%), male = female; 20-30 years; tend to be superficial; slow painless growth
Gross: expand the nerve in a fusiform fashion
Histologic features:
interlacing bundles of elongated cells with wavy nuclei
cells are usually intimately associated with densely eosinophilic collagen strands
there may be a moderate amount of mucoid material that separates the cells from the collagen, lending an overall “blue-ish” appearance to the tumor at low power.
stroma often contains mast cells, lymphocytes, and occasional xanthoma cells (lipid-laden histiocytes)
Immunohistochemistry: S-100 is positive, but not nearly as strong as is seen in schwannoma.
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