Sural nerve biopsy
An H&E stained specimen of the sural nerve (Figs 2A & 2B) revealed non-caseating granulomas with multinucleated giant cells in the epineurium. Perivascular mononuclear inflammatory infiltrates were highlighted with an immunohistochemical marker for CD45 (Fig. 3) A trichrome stain (Fig. 4) of blood vessel wall showed that it was invaded and damaged by inflammatory cells. Nerve infarction was not identified. Axonal degeneration was detected on teased fiber preparation (Fig. 5)
Muscle biopsy H&E stained paraffin sections of a medial gastrocnemius muscle biopsy (Figs 6A & 6B) revealed multiple non-caseating granulomas with minimal extension of the inflammatory infiltrate into the surrounding muscle fibers. Fite stain (Fig. 7) revealed no microorganisms.