Nemaline bodies

What it means

Nemaline rods are abnormal bodies that can occur in skeletal muscle fibers. The rods can be observed on histological analysis of muscle biopsy tissue or upon electron microscopy, where they appear either as extensions of sarcomeric Z-lines, in random array without obvious attachment to Z-lines (often in areas devoid of sarcomeres) or in large clusters localized at the sarcolemma or intermyofibrillar spaces.

This finding can be demonstrated by muscle biopsy, which shows nemaline bodies (rods) on Gomori trichrome staining. Rod bodies characteristically stain red with MGT. The rods are delicate and accumulate subsarcolemmaly. They stain negative with ATPase, NADH and SDH as they lack myosin and mitochondria. Rods are characteristic of nemaline myopathy but also seen in central core disease and various other diseases which include neurogenic disorders (amyotrophic lateral sclerosis, spinal muscular atrophy, undefined), inflammatory myopathies (dermatomyositis, polymyositis, periarteritis nodosa), metabolic myopathy (mitochondrial myopathy), muscular dystrophy (LGMD) and some undefined myopathies (Liouet al; Diagnostic role of nemaline rod in neuromuscular disease. Acta Neurol Sinica 1992;1: 218-23).

Rare diseases that can present with this10

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category

Also called: Nemaline rods