An Update on Nerve Biopsy

Abstract

Indications for nerve biopsy have decreased during the last 20 years. For the most part, this is a result of progress in the application of molecular biologic diagnostic testing for genetic peripheral neuropathies (PNs) and the increasing use of skin biopsy. The latter is primarily used to evaluate small-fiber PN, although it rarely discloses the specific etiology of a PN. Nerve biopsies are usually performed on either the sural or the superficial peroneal nerve, the latter in combination with removal of portions of the peroneus brevis muscle. The definite diagnosis of vasculitic lesions can be readily established on small paraffin-embedded nerve biopsy samples, although in some cases, the characteristic lesions are only apparent in muscle specimens. Other nerve specimens are routinely fixed in buffered glutaraldehyde and prepared for semithin sections and electron microscopy; frozen specimens are used for immunofluorescence studies. Electron microscopy is of great value in some cases of chronic inflammatory demyelinating polyneuropathies, monoclonal gammopathy, and storage diseases. Because more than 30 genes may be involved in genetic PNs, analysis of nerve lesions can direct the search for mutations in specific genes. Electron microscopy immunocytochemistry is mandatory in some cases of monoclonal dysglobulinemia. Thus, nerve biopsy is still of value in specific circumstances when it is performed by trained physicians and examined in a laboratory with expertise in nerve pathology.

CNTNAP1 mutations cause CNS hypomyelination and neuropathy with or without arthrogryposis

“…As described elsewhere, 9 samples of sciatic nerves were fixed for 3 hours in 2.5% glutaraldehyde in Sorensen buffer and osmificated for 1 hour in 1% OsO4. Afterward, they were rinsed in Sorensen buffer, dehydrated in graded acetone, and embedded in Epon.…”

Polyneuropathy associated with a monoclonal gammopathy

“…Many reports have confirmed monoclonal proteins localized in the myelin sheaths [28,[31][32][33][34]35]. Immunohistochemical analysis of sural nerve cross-sections reveals anti-MAG IgM antibody deposits on both large and small myelinated nerve fibers derived from patients with anti-MAG neuropathy (Fig.…”

“…The ultrastructural hallmark of anti-MAG neuropathy is the presence of fibers with widely spaced myelin (WSM) (Fig. 31.2B) in which the distance between neighboring intraperiod lines is increased [31,32] (Fig. 31.2C).…”

The Wide Range of Clinical Manifestations in Leprous Neuropathy: Two Case Reports

“…Tissue analysis is helpful and is often necessary to confirm and classify the disease. Histological diagnosis can be made on tissue from skin lesions in some cases (as in Case 2), but nerve biopsy is often required and can reveal this diagnosis in an apparently idiopathic peripheral neuropathy (8,9). Indeed, nerve biopsy is requisite to confirm the diagnosis of leprosy in patients without skin lesion as in Case 1.…”