Calcific myonecrosis: a report of ten new cases with an emphasis on MR imaging

Abstract

The aim of this study is to report the typical radiographic and MR imaging features of calcific myonecrosis, which help to distinguish this rare entity from other causes of a calcifying calf mass. Ten patients with a final diagnosis of calcific myonecrosis were referred to a specialist orthopaedic oncology service in a 5-year period with the presumptive diagnosis of malignancy based on recent clinical presentation and imaging findings. Radiographs were available for retrospective review in all ten cases and MR imaging in six. All patients presented with a slow-growing painless calf mass. All gave a history of major trauma to the lower leg many years before, but in only two cases did the referring clinician query whether trauma might be a contributory factor. Radiographs showed well-defined fusiform mineralised masses up to 25 cm in length arising within the calf. The calcification was consistently peripheral and plaque-like. Ossification was not present. MR imaging showed the anterior compartment to be involved in four cases and all compartments in two. T1- and T2-weighted images showed peripheral low signal intensity, more prominent on the T2-weighted images, because of the peripheral mineralization. The contents of the masses were variable on T1-weighted images depending on the differing amounts of blood breakdown products and were heterogeneous on T2-weighted images. The latter may be explained by a combination of the mineralisation and T2 shortening due to blood breakdown products. A gadolinium chelate, administered in two cases, failed to show any appreciable enhancement. Calcific myonecrosis has characteristic clinical, radiographic and MR features that should make the condition easy to recognise. Despite its rarity, it should be included in the differential diagnosis of focal mineralisation of the calf.

Skeletal muscle metastases: primary tumours, prevalence, and radiological features

“…In addition, MO occurs predominantly in the muscles of the extremities, although other localisations, such as paravertebral musculature are also known [55]. Other causes of muscle calcifications, such as calcific tendinitis, angiomatosis, systemic sclerosis, and calcific myonecrosis must also be considered [56][57][58][59]. Finally, 2.5% of SMM presented as local or diffuse intramuscular bleeding.…”

Calcific Myonecrosis of the Upper Extremity: Case Report

“…3,[5][6][7] The initial injury is usually a crush, fracture, or blunt trauma that caused vascular compromise or an untreated compartment syndrome 10 to 64 years before the presentation of the mass (average, 51 y after injury). 2,4 There is one report of calcific myonecrosis in a patient with a history of juvenile dermatomyositis and no history of trauma. 8 It is thought that neurovascular compromise leads to muscle necrosis and subsequent liquefaction and calcification of muscle tissue.…”

“…5 Observation, therefore, is becoming the preferred method of treatment for asymptomatic calcific myonecrosis, given a better understanding of the natural history of the disease and improving imaging techniques that allow for better visualization and characterization of calcific lesions. [3][4][5][6]32 Surgery might be indicated when (1) there is an infection or draining sinus that requires incision and drainage, (2) the patient's history and advanced imaging do not provide a clear diagnosis of calcific myone-FIGURE 2: Restricted motion limited conventional positioning of the arm for imaging. A Anteroposterior and B lateral plain radiographs show a fusiform, densely calcified mass in a severely atrophied forearm.…”

“…2,3,5,6,32 Calcific myonecrosis can be confidently diagnosed on radiographic and MRI studies due to its unique imaging characteristics. 4,7,9,32 Calcific myonecrosis is usually first identified on plain radiographs as a fusiform mass, with its long axis paralleling the extremity and containing plaque-like, linear, or amorphous calcifications within an atrophied muscular compartment. A CT can be used to evaluate these features in finer detail to confirm muscular atrophy and the lack of aggressiveappearing mineralized matrix.…”

Orthopaedic Case of the Month: Painful Lower-leg Mass in a 76-year-old Man

“…Occasionally, adjacent bony erosions with smooth contour can be present. MRI will show heterogeneous intensity on T1-and T2-weighted images owing to subacute hemorrhage and proteinaceous contents without enhancement after gadolinium administration [5].…”