This 50-year-old patient presented with a one yearhistory of of persistent muscle weakness. They also had shortness of breath with exertion. Their past medical history is significant for seropositive rheumatoid arthritis which has been well-managed symptomatically for several years with hydroxychloroquine. Laboratory studies showed elevated CPK (1000-1600 range), positive rheumatoid factor (>120), ANA (1:120), positive SSA/SSB, and negative/normal myositis specific autoantibody panel, CCP, dsDNA, Scl-70, Smith/RNP, smooth muscle and ANCA autoantibodies. Electrodiagnostic studies (EMG/NCS) showed features of a chronic active distal symmetric length dependent axonal polyneuropathy. The patient’s home medication list also included CellCept and prednisone. Simvastatin had been previously discontinued without significant improvement in the patient’s symptoms. On physical examination the patient was noted to have weakness involving both lower legs. What is your diagnosis based on clinical history, light microscopy and electron microscopy? #NeuroNotes #neuropath #pathology #neuromuscularpath

The patient is a 69-year-old male who presented with complaints of proximal lower extremity muscle weakness and BMI of 37. His home medication list includes atorvastatin. Bilateral thigh biopsies were performed to evaluate for myopathy. The significant finding can be seen in all of the following, except: A.SLONM B. ACTA1 mutations C.HIV D.Duchenne muscular dystrophy #NeuroNotes #neuropath #pathology #neuromuscularpath

This 45-year-old patient underwent sural nerve biopsy to evaluate for potential etiologies of their progressive sensorimotor predominantly axonal polyneuropathy. An extensive clinical workup did not identify a clinical cause for the patient’s neuropathy (i.e. idiopathic). What descriptive pathologic diagnosis would you use for the provided toluidine blue-stained thick section (prepared from glutaraldehyde-fixed EPON embedded tissue block)? An images of more normal appearing nerve fascicles is also provided. #NeuroNotes #neuropath #pathology #neuromuscularpath