Sankar Bandyopadhyay
Penn State College Of Medicine, USA
Title: Growing challenges with phenotype-based practice, muscle biopsy in neuromuscular diseases? A few novel presentations
Biography
Biography: Sankar Bandyopadhyay
Abstract
Introduction
Phenotype-based disease-classification and fixed histology, are not infallible.
Objective
Appreciation of novel phenotypes and histological findings.
Methods
Case studies. Histology.
Results
Case 1: 45 year-old woman with 10 year of proximal lower extremity, 2 year of bilateral finger flexion weakness with supportive objective evidence. CK 734. EMG and muscle biopsies: myopathic.
Presumptive Diagnosis: Early onset Inclusion Body Myositis.
Final diagnosis: Acid maltase deficiency (Adult onset Pompe disease), after Dried blood test and GAA sequencing, with novel IBM phenotype (MUSCLE & NERVE by same author)
Case 2: 53 year man with 2 years of progressive bilateral arms, forearms and thigh weakness. Objective weakness was corresponding. Prominent contractures of bilateral hamstrings and biceps. EMG and muscle biopsy: myopathic. Ck 162.
Phenotypic diagnosis: atypical late onset Emery-Dreifuss or Bethlem Muscular dystrophy.
Final diagnosis: 2B LGMD or Miyoshi myopathy.
Novel features: contractures, normal CK, hamstring type).
Case 3: 78 year man with 18 months of proximal lower extremity and distal upper extremity weakness. CK 379. EMG myopathic. Muscle biopsy: myopathic, rimmed vacuoles PLUS C5b-9 (seen in membrane attack complex disease e.g. dermatomyositis).
Final diagnosis: Sporadic IBM with Dermatomyositis histology profile.
Novel feature: C5b-9 positive staining in IBM (MUSCLE & NERVE by author). No response to immunosuppressives.
Case 4: 77 year old with 2 years of proximal LE and Grip weakness. CK 415. EMG and muscle biopsy: myopathic with rimmed vacuoles. TDP-43 positive (Sporadic IBM). Strongly positive C5b-9.
Final diagnosis: Sporadic IBM with Dermatomyositis histology profile.
Novel features: C5b-9 in IBM. TDP43 and C5b-9 co-existence.
Conclusion
Phenotype and histology based evidences are proving inadequate in neuromuscular diagnosis with growing evidences. Genotype is still a developing concept with caveats of unknown significance of variants.