Sarcoplasmic hexagonally cross-linked tubular arrays immunostain for caveolin-3: an excess caveolinopathy?

Suction-modified Bergström muscle biopsy technique: experience with 13,500 procedures

INTRODUCTION

Bergström needle muscle biopsies have been used by exercise physiologists for over 35 years but have been less accepted by neuromuscular clinicians due to size concerns.

METHODS

We retrospectively reviewed over 13,500 muscle Bergström needle biopsies done over a 21-year period to determine sampling success, patient/subject experience, and complications. We compared sample yield between two different needles (Bergström vs. UCH), with and without suction modifications.

RESULTS

Needle biopsies adequate for histology and enzymology were obtainable from the vastus lateralis, deltoid, biceps brachii, soleus, and medial gastrocnemius muscles, with a success rate of >99.9% and a minor complication rate of 0.15%. Approximately 450 muscle fibers were submitted for histologic assessment; suction modification and use of the Bergström vs. UCH needle were associated with larger sample size (P < 0.05).

CONCLUSIONS

The suction-modified Bergström needle muscle biopsy technique is safe and provides an adequate sample size for histologic, ultrastructural, DNA, and enzyme analysis.

Calsequestrin and junctin immunoreactivity in hexagonally cross-linked tubular arrays myopathy

We report on a patient with muscle pain not associated with muscle weakness. Microscopic examination of the muscle biopsy revealed rod-like cytoplasmic bodies in many fast fibres. By electron microscopy these had a crystalloid structure identical to the hexagonally cross-linked caveolin 3-positive tubular arrays, previously described in patients with similarly benign myopathy. We found that these inclusions were positive for calsequestrin and for the calsequestrin-binding protein junctin, as well as for caveolin 3. However, the genes coding for these proteins were not mutated. For diagnostic purposes calsequestrin and caveolin 3 positivity should be checked when rods are encountered in muscle biopsy for mild myopathy.