FIGURE 2.

Normal muscle in cryosections and salvaging biopsies from extreme ice crystal artifacts. (A) This hematoxylin and eosin photomicrograph shows the morphology of normal muscle in a biopsy that was prepared, sectioned, and stained optimally. (B, C) A muscle biopsy without diagnostic abnormality arrived with poor orientation and severe ice crystal artifacts. Thawing, reorienting, and refreezing restored the morphology, including the polygonal shapes of individual muscle fibers. (D, E) This biopsy is from a pediatric patient with autophagic vacuolar myopathy due to a mutation in VMA21 (X-linked myopathy with excess autophagy). After thawing and refreezing, the muscle fibers are rounded, but they have almost no ice crystals and small autophagic vacuoles are evident in some muscle fibers (arrows). Size scale bars: A–D = 100 µm; E = 50 µm.