Case Author(s): Stephanie P.F. Yen, M.D. and Keith Fischer, M.D. , 07/25/97 . Rating: #D5, #Q5

Diagnosis: Mazabraud Syndrome

Brief history:

72-year-old female with left lower extremity pain.

Images:

Anterior and posterior whole body scintigrams are shown.

View main image(bs) in a separate image viewer

View second image(xr). Anteroposterior view of the left tibia and fibula.

View third image(mr). Coronal T1, proton density, and T2-weighted images of the bilateral lower extremities.

View fourth image(mr). Axial T1 and T2-weighted FSE images of the left hip.

Full history/Diagnosis is available below

Diagnosis: Mazabraud Syndrome

Full history:

72-year-old female with history of a prior bone tumor removed from her left femur approximately 25 years ago with bone graft placement. The patient is recently status post surgery for removal of a soft tissue tumor from her left thigh which on histology was consistent with a soft tissue myxoma. She presents with left leg pain.

Radiopharmaceutical:

20.0 mCi Tc-99m MDP, intravenously

Findings:

The whole-body delayed scintigram demonstrates several foci of abnormally increased radiopharmaceutical uptake in the left lower extremity. Specifically, areas of increased activity involve the left superior pubic ramus/medial acetabulum, the proximal and mid-shaft of the femur, and the distal medial femoral condyle. More linear-appearing foci of activity are noted in the mid and distal left femur. Several foci of increased radiopharmaceutical uptake are seen in the left tibia. No abnormal activity is identified in the right lower extremity. Minimal diffuse activity is noted in the soft tissues of the lateral left thigh, likely post-operative in nature.

Discussion:

Mazabraud syndrome is a rare syndrome characterized by the presence of fibrous dysplasia and intramuscular myxomas. The syndrome was first described in 1957 by Mazabraud and Girard. Such an association between these two benign entities was first recognized in 1926 by Henschen. The underlying etiology accounting for this association is unknown. A review of the literature by Fujii et al. documents 26 reported cases. Of these 26 cases, 5 were monostotic fibrous dysplasia and 21 represented polyostotic fibrous dysplasia. Fifteen cases showed unilateral involvement of fibrous dysplasia, and ipsilateral intramuscular myxomas were found in 13 of these cases. While intramuscular myxomas are typically solitary, the majority of the reported cases of Mazabraud syndrome have demonstrated multiple intramuscular myxomas. Intramuscular myxomas are most commonly found in the thigh, shoulder, and buttocks. The intramuscular myxomas tend to be diagnosed many years following the diagnosis of fibrous dysplasia.

References: 1. Fujii K, Inoue M, Araki Y, et al. Multiple intramuscular myxomas associated with polyostotic fibrous dysplasia. Eur J of Rad. (1996) 22: 152-154. 2. Gober GA and Nicholas RW. Case report 800: Skeletal fibrous dysplasia associated with intramuscular myxoma (Mazabraud's syndrome). Skeletal Radiol (1993) 22: 452-455. 3. Prayson MA and Leeson MC. Soft-tissue myxomas and fibrous dysplasia of bone. A case report and review of the literature. Clinical Orthopaedics & Related Research. (1993) 291: 222-228.

Followup:

The areas of increased radiopharmaceutical uptake in the left lower extremity correspond to areas of radiographic abnormality in the left tibia and fibula as well as in the pelvis (not shown). Additionally, these osseous lesions demonstrate hypointensity on the T1-weighted images and hyperintensity on the T2-weighted sequence. The unilateral involvement and the radiographic characteristics of these osseous lesions favor polyostotic fibrous dysplasia.

The MRI study also demonstrates two soft tissue masses, one centered in the left iliopsoas muscle and the second in the left mid thigh in the vastus lateralis (not shown). Both these masses demonstrate hypointense T1 and hyperintense T2 signal. While non-specific, the signal characteristics are compatible with intramuscular myxomas.

ACR Codes and Keywords:

References and General Discussion of Bone Scintigraphy (Anatomic field:Skeletal System, Category:Misc)

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Case number: bs080

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