Why does it take months to get the results on a muscle biopsy?

Result of biopsy: It does not take months to get result of muscle biopsy or any other biopsy, but some pathologist in difficlt cases send the tissue to another expert pathologist in that field and that can delay the result.

Muscle biopsy: Muscle biopsies are more complicated than many other types of biopsies. they are processsed in a special way, with many stains that are specific to muscle disease. electron microscopic evaluation will usually be done, which is highly complex and not often done on other types of more routine biopsies. Only specialized labs can do these tests, and it does take longer (but weeks, not months)