case_images: PMC11724029_01
case_images: Histological appearances of the muscle biopsy. (a) Occasional necrotic fibers (arrow) were noted surrounded by fibers with increased internalized nuclei (HE x 100 mag.). (b) Some fibers displayed small vacuoles (arrow, HE x 200 mag.). (c and d) Several fibers contain large subsarcolemmal vacuoles (stars, HE x 400 mag.) and occasional pale fibers are seen, consistent with degenerate fibers (arrow in D, HE x 400 mag.). (e) Acid phosphatase was focally positive, compatible with degenerate/necrotic fibers (x 200 mag.). (f) Myophosphorylase was entirely negative in the myofibres (x 200 mag.). (g) PAS histochemistry was strongly positive in sarcoplasm and vacuoles (some PAS-positive material was lost during processing) (x 200 mag.). (h) Treatment with PAS diastase reveals negative staining in sarcoplasm and vacuoles, compatible with glycogen content (x 200 mag.).
case_images: CRIRH2025-8148736.001.jpg
case_images: PMC11724029_01_CRIRH2025-8148736.001.jpg
case_images: fig1
case_images: On H&E staining, occasional necrotic fibers were noted with increases in internalized nuclei (Figure 1(a), arrow, HE x 100 mag.). Some fibers displayed small vacuoles (Figure 1(b), arrow, HE x 200 mag), while others harbored large subsarcolemmal vacuoles (Figures 1(c) and 1(d), stars, HE x 400 mag.). Occasional pale fibers were noted, which indicated degenerate fibers (Figure 1(d), arrow, HE x 400 mag.). A histochemical preparation for acid phosphatase was focally positive and compatible with degenerate/necrotic fibers (Figure 1(e)). Histochemistry for myophosphorylase was entirely negative in the myofibres (Figure 1(f)). PAS histochemistry was strongly positive in fibers and vacuoles (although some loss of PAS-positive material during processing occurred), and treatment with PAS diastase revealed negative staining, compatible with glycogen (Figure 1(h)).