Case 6: Diagnostic case presentation

A 45-year-old female presented with a two-year history of slowly progressive paresthesias beginning with the 1^st, 4^th, and 5^th digits of her left hand and later involving the right forearm and lateral surfaces of her ankles. She endorsed a history of morning stiffness, joint pain and swelling. She had skin changes including hyperpigmented brown macules of the anterior neck and midline chest as well as erythematous changes to the malar region. A neurological examination revealed reduced sensation to pinprick and vibration in the areas of paresthesias. Nerve conduction studies showed evidence of an asymmetric multifocal large fiber sensorimotor neuropathy with prominent axonal features and mild demyelinating features. Laboratory investigations revealed an elevated Rheumatoid factor. Magnetic resonance imaging of the head and spine showed no significant abnormalities. The clinical impression was that of mononeuritis multiplex. A sural nerve biopsy was requested to investigate for vasculitis secondary to rheumatoid arthritis.

Questions

Probable diagnosis?

Diagnostic tests?

Materials submitted:

One H&E stained slide of sural nerve.