Journal of Electron Microscopy Advance Access originally published online on May 2, 2006
Journal of Electron Microscopy 2006 55(2):89-95; doi:10.1093/jmicro/dfl009
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Application of a quick-freezing and deep-etching method to pathological diagnosis: a case of elastofibroma
1 Department of Pathology, Nihon University Nerima Hikarigaoka Hospital 2-11-1 Hikarigaoka, Nerima, Tokyo 179-0072, Japan
2 Department of Pathology, Nihon University School of Medicine 30-1 Oyaguchi Kamimachi, Itabashi, Tokyo 173-8610, Japan
3 Department of Anatomy, Interdisciplinary Graduate School of Medicine, University of Yamanashi 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan
*To whom correspondence should be addressed. E-mail: ahemmi{at}med.nihon-u.ac.jp
A case of elastofibroma in a middle-aged Japanese woman was examined by the quick-freezing and deep-etching (QF-DE) method, as well as by immunohistochemistry and conventional electron microscopy. The slowly growing tumor developed at the right scapular region and was composed of fibrous connective tissue with unique elastic materials called elastofibroma fibers. A normal elastic fiber consists of a central core and peripheral zone, in which the latter has small aggregates of 10 nm microfibrils. By the QF-DE method, globular structures consisting of numerous fibrils (5–20 nm in width) were observed between the collagen bundles. We could confirm that they were microfibril-rich peripheral zones of elastofibroma fibers by comparing the replica membrane and conventional electron microscopy. One of the characteristics of elastofibroma fibers is that they are assumed to contain numerous microfibrils. Immunohistochemically, spindle tumor cells showed positive immunoreaction for vimentin, whereas alpha-smooth muscle actin, desmin, S-100 protein and CD34 showed negative immunoreaction. By conventional electron microscopy, the tumor cell had thin cytoplasmic processes, pinocytotic vesicles and prominent rough endoplasmic reticulum. Abundant intracytoplasmic filaments were observed in some tumor cells. Thick lamina-like structures along with their inner nuclear membrane were often observed in the tumor cell nuclei. The whole image of the tumor cell was considered to be a periosteal-derived cell, which would produce numerous microfibrils in the peripheral zone of elastofibroma fibers. This study indicated that the QF-DE method could be applied to the pathological diagnosis and analysis of pathomechanism, even for surgical specimens obtained from a patient.
Keywords benign tumor, elastofibroma, quick-freezing, deep-etching, electron microscopy, immunohistochemistry
Received 12 January 2006, accepted 22 March 2006