Fingerprint inclusions and circular structures in the muscle. Report of a case.

Fingerprint inclusions, circular structures of unknown origin, mitochondrial changes, dilatation of the sarcoplasmic reticulum, rods of Z-line material, elongated T-systems, honeycombs, and myelin figures were present in some damaged muscle fibres. Many damaged fibres showed loss of myofilaments and groups of atrophied fibres occurred. The muscle biopsy was from the left biceps brachii and presented also the changes of polymyositis. The patient had muscle weakness, malignant hypertension, alcoholism, polyarthropathy, and evidence of mild peripheral neuropathy.