Monomelic muscle atrophy

A case of intraneural perineurioma presenting with monomelic atrophy in a child

We report the case of an 11-year-old girl who developed slowly progressive atrophy of the left lower extremity. She suffered from mild dilated cardiomyopathy of unknown cause since 4years of age. When she was 7years old, her family noticed that her left extremity was thinner compared to the right one. Computed tomography showed atrophy and areas of low density in the left gluteus maximus, thigh, and calf muscles. The left sciatic nerve showed gadolinium enhancement on magnetic resonance imaging. A biopsy of the left sural nerve revealed pseudo-onion bulbs. Immunohistochemical staining was positive for epithelial membrane antigen and negative for S100 protein. Electron microscopy demonstrated myelinated or unmyelinated nerve fibers surrounded by concentric layers of perineurial cells. These results indicated intraneural perineurioma. The tumor was estimated at least from the nerve root to the ankle joint. The length of nerve involvement in this patient was the highest recorded in the literatures. Intraneural perineurioma is a very rare disorder, but is tend to be found in youth. This disorder should be considered when we see children with monomelic weakness and/or atrophy.

Monomelic neurogenic syndromes: a prospective study

Monomelic neurogenic syndromes are rare. Their classification and prognostic features have not been addressed in the European population. A prospective study of 17 patients with monomelic neurogenic amyotrophy, of upper or lower limb onset, with progression limited to one limb for three or more years. Clinical and neurophysiological studies were performed in the subsequent 3 or more years. Fifteen patients were of European origin and two were Asian. Those presenting with proximal monomelic weakness or with involvement of the posterior compartment of the lower leg showed no further progression after the initial period of development of the syndrome. Brisk reflexes in wasted muscles did not predict progression. Electromyographic signs of denervation in the opposite limb at presentation did not predict later progression. Transcranial magnetic stimulation (TMS) features of corticospinal dysfunction were a useful predictor of subsequent progression (p=0.01). One patient with lower limb onset developed conduction block with weakness in an upper limb nine years after presentation, and this upper limb weakness responded to IVIg therapy. This adult-onset European group of patients is different as compared with juvenile-onset Asian cases. The clinical syndromes appear heterogeneous, but neurophysiological investigations, in particular TMS, can be helpful in determining prognosis. Multifocal motor neuropathy should be considered when there is progression, even years after onset.

Diagnosis of amyotrophic lateral sclerosis

This review of the differential diagnosis of amyotrophic lateral sclerosis focuses on two themes. The first is practical, how to establish the diagnosis based primarily on clinical findings buttressed by electrodiagnosis. The main considerations are multifocal motor neuropathy and cervical spondylotic myelopathy. The second theme is the relationship of motor neuron disease to other conditions, including benign fasciculation (Denny-Brown, Foley syndrome), paraneoplastic syndromes, lymphoproliferative disease, radiation damage, monomelic amyotrophy (Hirayama syndrome), as well as an association with parkinsonism, dementia and multisystem disorders of the central nervous system.