Histopathological, Ultrastructural, and Immunohistochemical Findings in MYH11-Variant Visceral Myopathy. (January 2023)

• Record Type: Journal Article
• Authors: Kapur, Raj P.
• Is Part Of: Pediatric and developmental pathology. Volume 26:Number 1(2023)
• Page Start: 39
• Page End: 51
• Publication Date: 2023-01
• Subjects: myosin heavy chain -- visceral myopathy -- intestinal pseudo-obstruction -- MYH11 -- megacystis microcolon intestinal hypoperistalsis syndrome -- immunohistochemistry; Pediatric pathology -- Periodicals; Children -- Diseases -- Periodicals; Diagnosis, Laboratory -- Periodicals; Abnormalities, Human -- Periodicals; Child development -- Periodicals; Pediatrics -- Periodicals; 616.07
• DOI: 10.1177/10935266221128133
• Languages: English
• ISSNs: 1093-5266

Abstract

Background: Pathogenic mutations in the smooth muscle myosin heavy chain gene, MYH11, cause megacystis megacolon intestinal hypoperistalsis syndrome and other forms of chronic intestinal pseudo-obstruction. Evaluation of intestinal tissues from affected patients is often performed before mutational analysis, but the pathological findings of MYH11 -variant visceral myopathy have not been well defined. Methods: Light microscopic, immunohistochemical, and ultrastructural findings from multiple intestinal samples from 2 patients with MYH11-variant visceral myopathy were reviewed, including MYH11-specific immunohistochemistry. The findings were compared with intestinal samples from patients with gamma-smooth muscle actin ( ACTG2 )-variant visceral myopathy and non-pseudo-obstruction controls. Results: Apart from non-specific changes (e.g., muscle hypertrophy and distension-related muscularis propria necrosis), no alterations were identified by routine histopathological evaluation or electron microscopy. Immunohistochemistry with antibodies against a battery of smooth muscle proteins, including MYH11, revealed indistinguishable patterns of immunoreactivity in the muscularis propria of both patients and controls. Conclusions: Myopathic morphological or immunohistochemical changes may not be present in intestinal specimens from patients with MYH11 -variant visceral myopathy. Molecular genetic studies should be considered for patients with chronic intestinal pseudo-obstruction and normal or non-specific pathology findings.