Chronic denervation usually results in atrophy of muscular tissue. Nevertheless, it may rarely result in muscle pseudohypertrophy, an entity which has been reported in patients with chronic radiculopathy, peripheral nerve injury, poliomyelitis, neurinoma, anterior horn-cell diseases and tethered cord syndrome.1,2,3,4,5 The aim of our study is to evaluate the ability of MRI in diagnosing calf pseudohypertophy.

Five patients (6-58 years) with unilateral painless calf enlargement underwent MRI in order to rule out tumor. Two patients had a history of remote trauma, one patient had a history of poliomyelitis, and two patients had a history of chronic radiculopathy. None of them had a history of primary muscle disease. MRI images of the affected muscles were obtained before and after intravenous administration of gadolinium. In all patients diagnosis was confirmed by biopsy. Additionally, three patients underwent MRI of the lumbar spine. Electromyography was...

MR imaging studies revealed unilateral enlargement of the calf muscles with lipomatous replacement of muscular tissue in three of the patients and the presence of fat interspersed among muscle fibers in the other two. There was no disturbance of the normal architecture of the affected muscles and in all patients except one there was no pathologic enhancement. The histopathologic results of all patients were negative for malignancy and disclosed atrophy of muscular fibers with variable amounts of fat. In two patients with a history of...

In cases of painless calf enlargement the demonstration on MRI of fat deposition without disturbance of the muscles architecture is highly suggestive of neurogenic pseudohypertrophy.

1. Gobbelé R, Schoen SW, Schröeder JM, Vorwek D, Schwarz M. S-1 radiculopathy as a possible predisposing factor in focal myositis with unilateral hypertrophy of the calf muscles. J Neurol Sci 1999 Nov 15;170:64-68. 2. Swartz KR, Fee DB, Trost GR, Waclawik AJ. Unilateral Calf Hypertophy Seen in Lumbosacral Stenosis. Spine 2002 Sep 15;27(18): E406-9. 3. Coles A, Dick D. Unilateral calf hypertrophy. J Neurol Neurosurg Psychiatry 2004 Nov;75(11):1606. 4. Bertorini TE, Igarashi M. Postpoliomyelitis muscle pseudohypertrophy. Muscle Nerve 1985 Oct;8(8):644-649. 5. de Visser M,...

All authors: Athens Medical Center CT and MR Department Distomou 5-7, Maroussi, 15125 Athens, Greece email addresses: J. Pantazis: [email protected] G. Michailidis: [email protected]