[Characterization of eosinophils in soft tissue eosinophilic granuloma]

Soft tissue eosinophilic granuloma assumes the form of a poorly-demarcated painless mass, and is characterized by marked eosinophil infiltration. Although this tumor decreases in size in response to steroid therapy, it grows again after discontinuation of it, and ultimately proves intractable to treatment. We recently attempted to characterize electron-microscopically the eosinophils in the area affected by soft tissue eosinophilic granuloma.

Needle biopsy of subauricular masses was carried out before and after steroid treatment. The collected tissue was observed under an electron microscope.

Before treatment, more than 90% of the eosinophils constituting the granulation tissue had a broken cell membrane. A number of Charcot-Leyden crystals were noted in the intercellular spaces. Following steroid treatment, more than 90% of eosinophils were intact, and Charcot-Leyden crystals were no longer observed.

These findings suggest that destruction of eosinophils within granulation tissue aggravates soft tissue eosinophilic granulom.