To highlight an unusual presentation of sporadic late onset nemaline myopathy (SLONM) initially manifesting with cranial mononeuropathies.

SLONM is a rare muscle disease presenting in adulthood with progressive muscle weakness. Histopathologically, it is marked by the presence of nemaline rods in muscle fibers, with minimal to no inflammation. SLONM can present with a wide variety of manifestations, including bulbar, axial and proximal weakness. Severe neck or back pain at onset is relatively common in SLONM. However, cranial mononeuropathies as an initial presentation have not yet been reported.

The first patient was a 49-year-old female who presented with a 3-year history of left-followed-by-right sided facial numbness and burning sensation, primarily affecting the V1 and V2 distributions, and dysgeusia. One year later, she developed progressive lower followed by upper limb weakness, dyspnea, and dysphagia. Examination showed bulbar and proximal limb weakness, severe bilateral facial sensory loss, and mild length-dependent sensory deficits. The second patient was a 75-year-old female who presented with one-year history of left-more-than-right sided facial numbness, and dysgeusia, followed by mild dysphagia and head drop. Examination showed left hemiface numbness, tongue weakness, and head drop without limb weakness. EMG in both patients demonstrated bilateral trigeminal neuropathies and a myopathy with fibrillation potentials. Both patients had an IgG monoclonal protein and normal creatine kinase levels. HIV testing was negative in both. Diagnosis of SLONM was established by muscle histopathology demonstrating the accumulation of nemaline rods in mostly atrophic muscle fibers. First patient is being treated with IVIG. The second was treated with lenalidomide with partial improvement in her weakness and facial numbness.

Herein, we underscore the rare occurrence of cranial neuropathies at presentation in patients with SLONM, expanding the clinical spectrum of this condition.