Sarcoid polyneuropathy masquerading as chronic inflammatory demyelinating polyneuropathy.

INTRODUCTION: Sarcoid polyneuropathy is a rare and clinically heterogeneous disorder that may be the initial presentation of sarcoidosis. METHODS: We report the clinical, electrophysiological, and pathological findings of a patient who carried a diagnosis of sensory-predominant chronic inflammatory demyelinating polyneuropathy (CIDP) for over a decade but was ultimately found to have sarcoid polyneuropathy. RESULTS: A 36-year-old man presented with a several-week history of gait difficulty and muscle cramps. He had a diagnosis of CIDP but had not received lasting benefit from steroid-sparing immunosuppressive drugs. Electrodiagnostic studies were consistent with a chronic demyelinating polyradiculoneuropathy with conduction blocks. After he developed systemic symptoms, tissue biopsies revealed granulomatous disease. Symptoms improved with steroid therapy. CONCLUSIONS: Sarcoid polyneuropathy presents a diagnostic challenge, but, in patients with atypical neuropathy, characteristic systemic symptoms, or a poor response to standard treatment, nerve and muscle biopsies can help diagnose this treatable disorder.

Amyloid polyneuropathy caused by wild-type transthyretin.

INTRODUCTION: Amyloidosis derived from transthyretin (TTR) molecules is typically caused by mutations of the TTR gene. METHODS: We describe an elderly patient with a severe length-dependent polyneuropathy that unexpectedly proved to be caused by wild-type transthyretin amyloidosis. RESULTS: The diagnosis was made by muscle biopsy, because no amyloid deposits were found in the biopsied nerve segment. Most cases of wild-type transthyretin amyloidosis occur in elderly patients with cardiomyopathy, but a few cases of polyneuropathy have been reported. CONCLUSIONS: This entity is especially noteworthy in light of emerging treatment options for hereditary transthyretin amyloidosis, which are likely to also be beneficial in wild-type disease.

Adult nemaline myopathy with trabecular muscle fibers.

The term "trabecular myopathy" has been used to designate a syndrome resembling limb-girdle muscular dystrophy in which the predominant pathological feature is an abundance of lobulated or trabecular muscle fibers. However, the validity of this nosological entity has not been verified. Herein we describe a 63-year-old man with a severe, progressive myopathy who exhibited the typical pathological features of both trabecular myopathy and nemaline myopathy in association with a biclonal gammopathy. In this case, adult-onset nemaline myopathy was probably the primary disease process. The diagnostic significance of trabecular muscle fibers remains uncertain.

Myasthenia gravis and Lambert-Eaton myasthenic syndrome in the same patient.

An 18-year-old-woman developed symptoms of generalized myasthenia gravis (MG). Antibodies to the acetylcholine receptor were found in her serum, but electrodiagnostic testing showed abnormalities typical of the Lambert-Eaton myasthenic syndrome (LEMS). Following thymectomy, the thymus gland showed thymic hyperplasia typical of MG, and the patient responded to treatment with 3,4-diaminopyridine and pyridostigmine. There have been few reports in the literature of MG and LEMS coexisting in the same patient. In this case, electrodiagnostic tests, antibody studies, thymus pathology, and response to treatment suggest that both disorders contributed to the patient's symptoms. Thymic hyperplasia, so far only known to be associated with MG, provides strong evidence that both diseases were symptomatic.