Histopathology of Skeletal Muscle in Experimental Chagas' Disease

I. Alterations in Acute Trypanosoma cruzi Infection

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Summary and Conclusions

Histological skeletal muscle lesions found in the acute stage of Chagas' disease were studied in mice.

Almost all the mice infected with Trypanosoma cruzi developed a “polymyositis” with interstitial and parenchymatous lesions. The complete histological picture of the myositis was characterized by mononuclear cell infiltration of the perimysium, waxy degeneration of fiber segments, the presence of pseudocysts and granulomatoid foci in the muscle fibers, panarteritis of small intramuscular vessels, and regeneration of the muscle fibers. The infiltrates and the phenomena of waxy degeneration were the changes most constantly seen. Not all of the damaged muscles showed a florid histological picture. In many instances there was a non-specific myositis without pseudocysts and granulomatoid foci. The waxy degeneration and the interstitial infiltration very often presented no direct relationship to the presence of parasites. In the differential diagnosis of chagasic myositis, other necrobiotic and parasitic myosites must be considered.

Author Notes

Laboratory of Neuropathology and Department of Pathologic Anatomy of the University of Recife Medical School.

Department of Pathologic Anatomy of the University of Recife Medical School.

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