Scanning electron microscopy of dermatofibroma

Abstract

Dermatofibroma is a proliferation of spindle cells located in the dermis. We used scanning electron microscopy to examine two histologically confirmed lesions and observed preserved collagen bundles in the perilesional area. In the lesional area, the collagen was denser, without formation of bundles. Higher magnification showed collagen with mesh-like appearance similar to stretched tufts of cotton. Very high magnification evidenced the tufts of cotton and spindle cells measuring 2 to 12 microns.

Figure 1

Light Microscopy - A - Collagen homogenization with cell proliferation (asterisks) with normal collagen in the lower portion (NC) (hematoxylin & eosin, x150). B - similar aspect in the lesion border, with involvement of the papillary dermis (hematoxylin & eosin, x150). C - detail of the fusiform cells (arrows) (hematoxylin & eosin, x400). D - diminished elastic fibers in the homogenous area, with clear demarcation of normal elastic tissue (arrows) in the lower portion (Weigert’s stain, x150)

Figure 2

Scanning electron microscopy. A - Low magnification of the perilesional area with normal collagen bundles (x450). B - High er magnification of normal collagen bundles (x1.700). C - Low mag nification of the lesional area with compact tufted collagen (x450). D - Higher magnification of affected compacted collagen (x2.000)

Figure 3

Scanning electron microscopy. A - Detail of the affected area with tufted collagen without bundle formation (x3.000). B e C - Detail of fusiform cells, measuring 2 to 12 microns (x7,000 and x8,000)