Morphological and histochemical studies on the collagen in neurinomas, neurofibromas, and fibromas.

The collagen in neurinomas, neurofibromas was studied by optical and electron microscopy. Neurinomas were shown to be composed mainly of thin argyrophilic, weakly birefringent fibers formed by thin collagen fibrils. Fibromas presented only thick, non-argyrophilic, strongly birefringent fibers composed of thick collagen fibrils. Neurofibromas showed populations of the two above-mentioned types of fibers occupying different areas of their parenchyma. These results suggest that the collagen of neurinomas is mainly of type III, while fibromas present collagen type I, and neurofibromas are composed of both types of collagen.