Best Post of May 2013: Angulated intramitochondrial inclusions in the left leg of a man with a left-sided limp

Here's the next in our Best of the Month Series. No definitive diagnosis has been suggested since the original post on May 9, 2014:

A 59-year-old male with a one-year history of limping as well as pain, weakness, and paresthesia of the left lower extremity who underwent lumbar microdiscectomy with cord decompression. Although the patient's pain subsided post-operatively, his other symptoms persisted. Since his CPK levels were chronically elevated (around the 500's), biopsies were later performed on the quadriceps bilaterally. Light microscopic examination was underwhelming except for some denervation effect on the left. However, subsarcolemmal clumping was evident with NADH histochemisty on both the right and left. This clumping prompted me to perform an ultrastructural examination, which revealed the following angulated intramitochondrial inclusions IN THE WEAK LEG ONLY:

These inclusions were present in about 5% of mitochondria.  I reported out my findings in a descriptive manner, not certain of their significance. If anyone has seen such intramitochondrial inclusions in a specimen, please comment. As of now, the patient has no definitive diagnosis.