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Age / Sex : /
Age / Sex : 74 / M
Chief complaint : Slowly growing mass
Past History : Fall down injury, 40 years ago
1) What is your impression?
Two weeks later, you can see the final diagnosis with a brief discussion of this case.
* Send Application Answers to Ja-Young Choi, MD ([email protected])
Courtesy : Wan Tae Kim, MD., Seoul Veterans Hospital.
Diagnosis: calcific myonecrosis
Discussion
Findings:
Radiographs show a fusiform soft tissue mass with peripherally oriented plaque like amorphous calcifications. MRI shows a well-circumscribed mass with heterogenous signal on T2-weighted sequences and a homogenous high signal throughout the central fluid lesion on T1-weighted images. On T1-weighted images the mass shows a thick nodular dark rim corresponding to the distribution of the calcification. The liquid center has a high signal on T2-weighted sequences. The mass does not show enhancement after gadolinium administration, presumably secondary to extensive necrosis.
Differential Diagnosis:
Hematoma Myositis ossificans Diabetic myonecrosis Synovial sarcoma Epithelioid sarcoma Soft tissue osteosarcoma
Diagnosis: Calcific Myonecrosis
Discussion:
Calcific myonecrosis is a rare complication that may occur several decades after trauma of the limb. It may be associated with a compartment syndrome or nerve injury. The clinical presentation is typically a painless, enlarging soft tissue mass in the lower leg. Radiographs reveal a fusiform mass with peripherally oriented plaquelike amorphous calcifications. The calcifications are usually linear in orientation and sheetlike, and they present within the entire muscle or compartment. The MRI signal characteristics reflect the pathologic nature of this disease entity, The mass is hyperintense on both T1- and T2-weighted images, consistent with blood or proteninaceous material. The lack of flow voids or enhancement reflects the avascular nature of the mass. Biopsy should be avoided because of the high risk of complications and the possibility for conversion of sterile necrotic tissue into an abscess. The treatment of calcific myonecrosis involves complete surgical excision if the condition is symptomatic.
References:
1. O’Dwyer HM, Al-Nakshabandi NA, Al-Muzahmi K, et al. Calcific myonecrosis: keys to recognition and manangement, AJR Am J Roentgenol 2006;187(1):W67-76
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