Age / Sex : 78 / M

Chief complaint: Left heel mass. resently enlarged

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Courtsy: Chang Ho Kang, Korea University Anam Hospital

Ossifying fibromyxoid tumor

Discussion

Findings:

 Plain radiograph showed a soft tissue mass with amorphous calcification or ossification. Magnetic resonance imaging (MRI) revealed a well-defined subcutaneous mass. The mass exhibited low to intermediate signal intensity on T1-weighted sequences and heterogeneous high signal intensity, with foci of low signal intensity, on T2-weighted sequences. A fine low signal was observed on both T1- and T2-weighted sequences. Contrast-enhanced T1-weighted sequences demonstrated heterogenous and mild enhancement throughout the mass.

Differential Diagnosis:

 A number of benign and malignant conditions, including myositis ossificans, ossifying hematoma, extraskeletal chondroma, low-grade fibromyxoid sarcoma, synovial sarcoma and extraskeletal osteosarcoma

Discussion:

 Ossifying fibromyxoid tumor (OFMT) is a rare soft tissue tumor of uncertain differentiation with intermediate (rarely metastasizing) aggressiveness. OFMT predominantly arises in the subcutaneous tissue of extremities, and the age of presentation ranges from 14–83 years, and the median age at presentation is 49 years. Clinically, the tumor often presents as a small, slow-growing, painless, well-defined mass that displays a peripheral incomplete ring of ossification on radiography. OFMTs consist of small round cells dispersed in a myxoid matrix and contain varying amounts of bone, osteoid, and collagen. There are few reports describing the imaging features of OFMTs.

References:

1. Enzinger FM, Weiss SW, Liang CY. Ossifying fibromyxoid tumor of soft parts. A clinicopathological analysis of 59 cases. Am J Surg Pathol 1989;13(10): 817–827.


2. Ogose A, Otsuka H, Morita T, Kobayashi H, Hirata Y. Ossifying fibromyxoid tumor resembling parosteal osteosarcoma. Skelet Radiol 1998;27(10): 578–580.


3. Schaffler G, Raith J, Ranner G, Weybora W, Jeserschek R. Radiographic appearance of an ossifying fibromyxoid tumor of soft parts. Skelet Radiol 1997;26(10): 615–618.


4. Akai M, Azuma H, Ohno T, Kimura H, Sugano I, Nagao K. Case report 685: ossifying fibromyxoid tumor of the soft parts of the upper arm. Skelet Radiol 1991;20(8): 608–612.


5. Harish S, Polson A, Morris P, Malata C, Griffiths M, Bearcroft PW. Giant atypical ossifying fibromyxoid tumour of the calf. Skelet Radiol 2006;35(4): 248–253.