Figure 1
Scout from abdominal CT
Scout from the abdominal CT, shows subtle hyperdensities projecting bilaterally over the hip joints.
Myositis ossificans of the gluteal muscles
SectionMusculoskeletal system
Case TypeClinical Cases
AuthorsPapaioannou G, Tavernaraki K, Kelekis DA
Connected authors
74 years, male
Clinical History
We present the case of a 74-year-old male patient with central paresis of the right peroneal nerve.
Imaging Findings
The patient had a history of left hemicolectomy 4 months previously due to intestinal ischemia from inferior mesenteric artery thrombosis. The severity of his post-surgical course had forced him into
prolonged immobilization during which he had suffered from multiple decubitus ulcers, mostly in the sacral region, and atrophy of the gastrocnemius and the quadriceps muscles. An EMG was performed
and revealed central paresis of the right peroneal nerve. CT examination of the abdomen performed at that time demonstrated bilateral, linear calcifications of the gluteal muscles, more prominent on
the right, adjacent to the anatomic site of the sacral nerve.
Discussion
The course of the sacral
nerve is as folows: it exits from the pelvis through the subpiriform fissure and passes from the posterior surface of the internal thyroid muscle. It consists of two major trunks, the tibial nerve
and the common peroneal nerve, which are surrounded by a common sheath, and they divide into two separate parts at a different anatomic height in each individual. In case of a division at the level
of the pelvis, the peroneal nerve exits through the piriform muscle.
Myositis ossificans (MO) is a condition characterized by focal, benign and self-limiting heterotopic bone formation typically occuring within the skeletal muscle or soft tissue with unknown
pathogenesis. It is most often caused by trauma (MO traumatica or circumscripta), or other froms of tissue injury (surgical procedures or prolonged immobility). In these cases, hematoma formation,
tissue injury and anoxia are possible predisposing factors. Sometimes MO may develop without known trauma. In addition, there is another form, Fibrodysplasia ossificans progressiva , which is a very
rare autosomal dominant genetic disorder where the ectopic ossification begins in early childhood. It is characterized by episodes of permanent heterotopic ossification of soft tissues, occurs
worldwide without racial, ethnic, or geographic predilection. There is no effective treatment, and soft-tissue trauma (eg, biopsies, surgical procedures, intramuscular injections, or mandibular
blocks for dental procedures) and viral illnesses are likely to induce episodes of rapidly progressive heterotopic ossification, with resultant permanent loss of motion in the affected area.
Favourite locations of MO development are the extremities, particularly the thigh, hip, elbow, shoulder and knee, although unusual locations such as the paravertebral muscles have been reported. The
most frequently occurring symptoms are pain, tenderness and the presence of a soft tissue mass; however the lesion may be an incidental finding. Local excision is generally curative.
On CT scans, MO usually appears as a ring-like structure with a variable degree of calcification or ossification. Its center is isodense or hypodense as compared to the surrounding muscle. The degree
of peripheral calcification continuously increases. The calcified structures may appear as being punctiform or cloudy, but are subtly radial. They may partially or completely fill the mass. There are
no specific imaging findings for MO and by using imaging alone it is usually difficult to differentiate between the different types of MO and other pathologies, such as inflammatory lesions and
neoplasms. However, the imaging history, for example a previously demonstrated hematoma on US, may indicate the traumatic form, and the presence of lesions in a child which progressively deteriorate
and expand, the heritable form.
The differential diagnosis of MO mostly includes the possibilities of extraskeletal or juxtacortical osteosarcoma but also extraskeletal osteochondroma, chondrosarcoma, reactive periostitis (when the
MO is located directly in the periosteum), tumoral calcinosis etc. Despite advances in medical imaging, it remains difficult to distinguish MO from other disorders. As a consequence, a biopsy is
frequently performed and is sometimes essential for the final diagnosis.
Differential Diagnosis List
Myositis ossificans of the gluteal muscles.
Final Diagnosis
Myositis ossificans of the gluteal muscles.
References
[1] Miller AE, Davis BA, Beckley OA. Bilateral and recurrent myositis ossificans in an athlete: a case report and review of treatment options.Arch Phys Med Rehabil. 2006 Feb;87(2):286-90.
[2] Kitterman JA et al. Iatrogenic harm caused by diagnostic errors in fibrodysplasia ossificans progressiva. Pediatrics. 2005 Nov;116(5):e654-61.
[3] Hendifar AE et al. Myositis ossificans: a case report. Arthritis Rheum. 2005 Oct 15;53(5):793-5.
[4] Saussez S et al. Non-traumatic myositis ossificans in the paraspinal muscles. Eur Arch Otorhinolaryngol. 2005 Aug 24;.
[5] Vanden Bossche L et al. Heterotopic ossification: a review. J Rehabil Med. 2005 May;37(3):129-36.
Case information
| URL: | https://www.eurorad.org/case/3091 |
| DOI: | 10.1594/EURORAD/CASE.3091 |
| ISSN: | 1563-4086 |
Figure 2
Ossifying myositis of the gluteal muscles bilaterally.
Serial axial scans at the level of the hip joints, showing coarse calcifications within the gluteus medius and minimus muscles bilaterally, especially on the right, with close proximity to the anatomic site of the sacral nerves.
Serial axial scans at the level of the hip joints, showing coarse calcifications within the gluteus medius and minimus muscles bilaterally, especially on the right, with close proximity to the anatomic site of the sacral nerves.
Serial axial scans at the level of the hip joints, showing coarse calcifications within the gluteus medius and minimus muscles bilaterally, especially on the right, with close proximity to the anatomic site of the sacral nerves.
Serial axial scans at the level of the hip joints, show coarse linear calcifications within the gluteus medius and minimus muscles bilaterally, especially on the right, with close proximity to the anatomic site of the sacral nerves.
Scout from abdominal CT
Scout from the abdominal CT, shows subtle hyperdensities projecting bilaterally over the hip joints.
Ossifying myositis of the gluteal muscles bilaterally.
Serial axial scans at the level of the hip joints, showing coarse calcifications within the gluteus medius and minimus muscles bilaterally, especially on the right, with close proximity to the anatomic site of the sacral nerves.
Serial axial scans at the level of the hip joints, showing coarse calcifications within the gluteus medius and minimus muscles bilaterally, especially on the right, with close proximity to the anatomic site of the sacral nerves.
Serial axial scans at the level of the hip joints, showing coarse calcifications within the gluteus medius and minimus muscles bilaterally, especially on the right, with close proximity to the anatomic site of the sacral nerves.
Serial axial scans at the level of the hip joints, show coarse linear calcifications within the gluteus medius and minimus muscles bilaterally, especially on the right, with close proximity to the anatomic site of the sacral nerves.