Diagnosis of Inflammatory Myopathy by Percutaneous Needle Biopsy with Demonstration of the Focal Nature of Myositis

Abstract

Inflammatory myopathies are a group of acquired disorders with histologic features of inflammation and nonspecific myopathic changes in the muscle fibers. Up to 25% of patients with clinical features of polymyositis reportedly have no inflammatory changes in their muscle biopsy specimens, but the absence of inflammatory infiltrates does not exclude an inflammatory myopathy. However, whether the lack of inflammation is caused by sampling variation or by a total lack of demonstrable inflammation in a particular patient has been unclear in the literature. The authors diagnosed polymyositis in six patients who underwent percutaneous muscle biopsy using a Bergstrom needle. Through one skin incision, the needle was inserted into different areas within the muscle compartment, obtaining three or four concurrent specimens from each patient. In all cases of needle biopsy, adequate tissue was obtained for histochemical and electron microscopic examination. All patients tolerated the procedure well and resumed normal daily activities the morning after biopsy. Although we saw inflammatory changes in at least one biopsy specimen from each patient, one or more of the remaining specimens contained no evidence of inflammation. This illustrates that inflammatory infiltrates can be focal in polymyositis. Because a specific diagnosis of inflammatory myopathy cannot be made in the absence of demonstrable inflammation, the diagnostic yield of multiple percutaneous needle biopsy specimen is potentially higher than that of the traditional single biopsy specimen obtained with the open surgical method.

Percutaneous needle muscle biopsy in the evaluation of patients with suspected inflammatory myopathy

“…Because of the patchy nature of IIM, some authors suggest that NMB has a higher yield than open biopsy, since more samples can be taken from the same muscle (9). In addition, it is easier to sample more than 1 muscle in an office visit with this method of percutaneous NMB than with other methods.…”

“…However, most NMB techniques require a skin incision that leaves a small scar (6,7), and require large bore tubes that utilize suction to deliver the muscle into the tube before it is guillotined (5, 8,9). A technique using a spring-activated 14-gauge needle is minimally traumatic and may be capable of obtaining diagnostic results historically comparable with more invasive techniques (10).…”

Utility of magnetic resonance imaging in the evaluation of patients with inflammatory myopathies

“…Needle biopsies of muscle are often less costly than open surgical biopsies, and the use of MRI to localize the needle placement site may improve the accuracy of the biopsy results [10,55]. Depending on the institution, even needle biopsy with related costs for pathology services may be considerably more expensive than the MRI.…”

Diagnosis of idiopathic myositis: value of 99m technetium pyrophosphate muscle scintigraphy and magnetic resonance imaging in targeted muscle biopsy

“…Even though diagnostic criteria for polymyositis and dermatomyositis have been developed [4,15,16], particularly in less defined inflammatory muscle diseases, typical histopathologic changes are generally considered as the diagnostic centerpiece. Due to the often patchy [23] and sometimes asymmetric [3,19] nature of idiopathic muscle inflammation, sampling errors may occur leading to false negative biopsy results. The present study therefore focused on the evaluation of diagnostic procedures that are able to detect areas of muscle inflammation and thus might increase the accuracy of muscle biopsy.…”