9/27/2005 Case 3: Extensive myopathy with deg/reg fibers and marked interstitial fibrosis

Clinical History:

This biopsy was from a 56 year old man who was referred to a rheumatologist for rigidity and stone-hard muscle allover his body. He gave a history of a flu-like syndrome in November 2004, after which he had a kidney problem (not otherwise described) requiring several weeks of hospitalization. After that he had progressive difficulty in walking and became more and more rigid over a time course of several months.

Diagnostic Notes:

The circulated H&E-stained slide showed muscle with extensive fibrosis. There were no other specific features, and the usual special stains were not indicative of any specific process. There were clearly degenerating and regenerating myofibers as well as an interstitial (endomysial) fibrosis. A diagnosis of Fibrosing Myopathy associated with renal failure, as described by our colleague Dr Lavi, was proposed during the case discussion. This was stated to be allied to "Sclerosing Dermopathy" in chronic renal failure. It was also mentioned that Dr Hays with Dr Treiburg had described some cases like this among a series of patients with Cri tical Illness Myopathy. Some in the group speculated about an episode of rhabdomyolysis leading to myoglobinuria as a cause of the renal failure as well as an initiating event for the muscle damage. The official NJMS diagnosis was one of Extensive Myopathy with Degenerating/Regenerating Fibers and Marked Interstitial Fibrosis.

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