Orthopedics

Radiologic Case Study 

Your Diagnosis?

Maxime Freire, MD; Priya S. Simonelli, DC, MS III

  • Orthopedics. 2010;33(7)
  • Posted July 1, 2010

Abstract

A 45-year-old woman presented with a left leg mass and medical history of tibia and fibula fracture due to a motor vehicle accident and multiple surgeries 30 years prior.

For answer click here.

Figure 1 shows a large fusiform-shaped area of calcification overlying the anterior compartment of the left leg extending from just below the proximal tibiofibular articulation to the level of the distal shaft of the fibula. Magnetic resonance imaging (MRI) showed extensive replacement of the lateral compartment muscles by a central high and peripheral low T1 signal and diffuse low T2 signal tissue (Figures 2, 3). Computed tomography (CT) performed for better characterization of the calcification pattern and distribution demonstrated predominantly peripheral distribution of the calcifications in the muscles of the lateral compartment (Figures 4, 5).

The patient presented here had a history of prior motor vehicle accident and multiple surgeries, and the imaging findings are consistent with calcific myonecrosis, particularly in view of an unequivocal history of previous trauma.

Calcific myonecrosis is a rare clinical entity occurring as a late consequence of trauma, usually in the lower limb,1 although there is at least 1 case report of this entity in the shoulder.2 It is characterized by the replacement of muscle in 1 or more compartments with a fusiform mass or masses showing peripheral calcification and central liquefaction.3 Reported cases are related to previous trauma1-4 except 1 that occurred in a patient with dermatomyositis.3 Patients usually report pain, and biopsy is not recommended due to the high risk of infection.4 The treatment for these lesions is complete excision.

The radiographic findings are characteristic in showing defined heavily mineralized fusiform masses replacing musculature.1,2 The 2 main differential diagnoses are sarcomas and myositis ossificans. Sarcomas are aggressive and do not respect compartments. Myositis ossificans presents with a different calcification pattern and ossification over time.4 Typically when heterotopic posttraumatic ossification develops in a hematoma, it shows a characteristic peripheral mineralization and is unlikely to be confused with calcific myonecrosis.

In the leg, calcific myonecrosis has a predilection for the anterior compartment. Unlike traumatic heterotopic ossification, the pattern of calcification in myonecrosis is linear and sheetlike and typically occupies the entire muscle or compartment. Magnetic resonance imaging may show fluid-filled cystic areas that should not be mistaken for abscesses or necrosis within a heavily mineralized sarcoma.

The proper recognition of calcific myonecrosis is based on the characteristic sheetlike calcification occupying an entire muscle or compartment with areas of central liquefaction, and it is almost always preceded by a remote significant traumatic event.

Drs Freire and Simonelli are from the Imaging Institute, Cleveland Clinic, Cleveland, Ohio.

Drs Freire and Simonelli have no relevant financial relationships to disclose.

Correspondence should be addressed to: Maxime Freire, MD, 9500 Euclid Ave, A21, Cleveland, OH 44195 (freirem@ccf.org).

doi: 10.3928/01477447-20100526-29 …

The Case:

A 45-year-old woman presented with a left leg mass and medical history of tibia and fibula fracture due to a motor vehicle accident and multiple surgeries 30 years prior.

Figure A: Radiograph of the left leg Figure B: Radiograph of the left leg
Figure: Lateral (A) and AP (B) radiographs of the left leg.

Your Diagnosis?

For answer click here.















Diagnosis:

Calcific Myonecrosis

Figure 1 shows a large fusiform-shaped area of calcification overlying the anterior compartment of the left leg extending from just below the proximal tibiofibular articulation to the level of the distal shaft of the fibula. Magnetic resonance imaging (MRI) showed extensive replacement of the lateral compartment muscles by a central high and peripheral low T1 signal and diffuse low T2 signal tissue (Figures 2, 3). Computed tomography (CT) performed for better characterization of the calcification pattern and distribution demonstrated predominantly peripheral distribution of the calcifications in the muscles of the lateral compartment (Figures 4, 5).

Figure 1A: A large fusiform-shaped area of calcification Figure 1B: A large fusiform-shaped area of calcification
Figure 1: Lateral (A) and AP (B) radiographs showing a large fusiform-shaped area of calcification overlying the anterior compartment of the left leg.

Figure 2A: Extensive replacement of the muscle Figure 2B: Extensive replacement of the muscle Figure 2C: Low-signal intensity
Figure 2: T1-weighted coronal image showing extensive replacement of the muscle of the lateral compartment of the leg for peripheral areas of low and central areas of high signal intensity (arrows) (A). STIR coronal demonstrating predominant low-signal intensity (arrows) (B). T2-weighted sagittal image without fat signal suppression also showing low-signal intensity (arrows) (C).

Figure 3A: Extensive replacement of the muscle Figure 3B: Low-signal intensity
Figure 3: T1-weighted axial image showing extensive replacement of the muscle of the lateral compartment of the leg for peripheral areas of low and central areas of high-signal intensity (arrows) (A). T2-weighted axial image with fat signal suppression showing low-signal intensity (arrows) (B).

Figure 4A: Predominantly peripheral calcifications Figure 4B: Predominantly peripheral calcifications Figure 5: Predominantly peripheral distribution of the calcifications
Figure 4: Coronal (A) and sagittal (B) CT reformats showing predominantly peripheral calcifications in the muscles of the lateral compartment (arrows). Figure 5: Axial CT reformat showing predominantly peripheral distribution of the calcifications in the muscles of the lateral compartment (arrows).

Discussion

The patient presented here had a history of prior motor vehicle accident and multiple surgeries, and the imaging findings are consistent with calcific myonecrosis, particularly in view of an unequivocal history of previous trauma.

Calcific myonecrosis is a rare clinical entity occurring as a late consequence of trauma, usually in the lower limb,1 although there is at least 1 case report of this entity in the shoulder.2 It is characterized by the replacement of muscle in 1 or more compartments with a fusiform mass or masses showing peripheral calcification and central liquefaction.3 Reported cases are related to previous trauma1-4 except 1 that occurred in a patient with dermatomyositis.3 Patients usually report pain, and biopsy is not recommended due to the high risk of infection.4 The treatment for these lesions is complete excision.

The radiographic findings are characteristic in showing defined heavily mineralized fusiform masses replacing musculature.1,2 The 2 main differential diagnoses are sarcomas and myositis ossificans. Sarcomas are aggressive and do not respect compartments. Myositis ossificans presents with a different calcification pattern and ossification over time.4 Typically when heterotopic posttraumatic ossification develops in a hematoma, it shows a characteristic peripheral mineralization and is unlikely to be confused with calcific myonecrosis.

In the leg, calcific myonecrosis has a predilection for the anterior compartment. Unlike traumatic heterotopic ossification, the pattern of calcification in myonecrosis is linear and sheetlike and typically occupies the entire muscle or compartment. Magnetic resonance imaging may show fluid-filled cystic areas that should not be mistaken for abscesses or necrosis within a heavily mineralized sarcoma.

The proper recognition of calcific myonecrosis is based on the characteristic sheetlike calcification occupying an entire muscle or compartment with areas of central liquefaction, and it is almost always preceded by a remote significant traumatic event.

References

  1. Wee B, Shimal A, James SL, Davies AM. Bilateral lower limb calcific myonecrosis: A case report. European Journal of Radiology Extra. 2007; 64(2):79-82.
  2. Larson RC, Sierra RJ, Sundaram M, Inwards C, Scully SP. Calcific myonecrosis: a unique presentation in the upper extremity. Skeletal Radiol. 2004; 33(5):306-309.
  3. Batz R, Sofka CM, Adler RS, Mintz DN, DiCarlo E. Dermatomyositis and calcific myonecrosis in the leg: ultrasound as an aid in management. Skeletal Radiol. 2006; 35(2):113-116.
  4. O’Dwyer HM, Al-Nakshabandi NA, Al-Muzahmi K, Ryan A, O’Connell JX, Munk PL. Calcific myonecrosis: keys to recognition and management. AJR Am J Roentgenol. 2006; 187(1):W67-76.

Authors

Drs Freire and Simonelli are from the Imaging Institute, Cleveland Clinic, Cleveland, Ohio.

Drs Freire and Simonelli have no relevant financial relationships to disclose.

Correspondence should be addressed to: Maxime Freire, MD, 9500 Euclid Ave, A21, Cleveland, OH 44195 (freirem@ccf.org).

doi: 10.3928/01477447-20100526-29

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