Mazabraud's syndrome: case report and literature review
A 54-year-old woman was referred to our clinic with a complaint of pain in her right gluteal region with radiation to her foot that had been present for 2 months. The pain was most pronounced during sitting and jogging, and a physiotherapist detected a mass in the proximal right semitendinosus muscle. She had no history of trauma and was otherwise healthy. However, she had a previous history of breast fibroadenomatosis, carcinoma in situ of the uterine cervix, and uterine fibroma.\nConventional X-rays of the right femur demonstrated a 9.5 × 3.3 cm intra-osseous cystic lesion with sclerotic margins at the right femoral neck in the subtrochanteric and metaphyseal region (Fig. a). A similar lesion was observed within the right ileum above the acetabulum (Fig. b). The lesions were interpreted as being consistent with fibrous dysplasia. Ultrasonography of the right gluteal region revealed a 3 × 4.2 × 4.5 cm hypoechoic soft tissue mass located in the musculature below the ischial tuberosity (not shown). There was no involvement of the adjacent bone. Moreover, the patient underwent magnetic resonance imaging (MRI) of her pelvis and right thigh with and without intravenous administration of a gadolinium-containing contrast agent. The examination showed multiple cystic and solid tumor-like lesions within the bones and muscles. The largest of the soft tissue masses was located in the proximal right adductor magnus muscle and measured 5.5 × 4.4 × 2.9 cm. Two similar lesions were observed in the proximal right adductor brevis muscle with diameters of 1.4 and 1 cm, respectively, and a lesion extending 1.3 cm was located in the rectus femoris muscle. The muscle masses showed low signal intensity on T1-weighted images and high signal intensity on T2-weighted images and short T1 inversion recovery (STIR) images. The signal intensity increased after contrast injection. Skeletal changes related to fibrous dysplasia were evident within the right ilium and in the proximal diaphysis of the right femur measuring 7 and 8 cm, respectively. The bone lesions demonstrated a slight thinning of the cortical bone but no real destruction. The bony lesions were typical of fibrous dysplasia, but the diagnosis of the soft tissue lesions was uncertain, including differentials such as soft tissue sarcoma, lymphoma, and neurofibroma (Fig. ).\nUltimately, the patient underwent an 18F-FDG PET/CT of the neck, chest, abdomen, and thighs at our clinic. The patient received an intravenous injection of 370 MBq of 18F-FDG at rest in dimmed ambient light with minimal background noise. The patient was asked to fast for 6 h before the bolus injection of FDG (water only). One hour after the injection, the PET/CT scan was performed under standard resting condition using a 64-channel PET/CT scanner (Discovery VCT, GE Healthcare, Milwaukee, WI, USA). Images were acquired for 2.5 min in three-dimensional (3D) mode and were filtered and reconstructed using standard techniques. The examination demonstrated a slightly increased FDG uptake (standardized uptake value [SUV] max 2.1) within the solid-appearing regions of the intramuscular lesions in the right hip and thigh and the findings were interpreted as intramuscular myxomas. Moreover, we observed moderately to highly increased tracer uptake (SUVmax 7.0) within the right ilium and the proximal diaphysis of the right femur that was consistent with fibrous dysplasia. The accompanying CT findings were concordant, demonstrating multiloculated and expansive intramedullary lesions with areas of both thickening and thinning of the cortical bone but without cortical destruction. The areas with FDG-uptake on the PET/CT also showed contrast enhancement on the MRI with intravenous gadolinium (Figs. and ). The scan showed no signs of malignancy; thus, enlarged lymph nodes or FDG uptake in lymph nodes was not observed in the neck, chest, and abdomen. The spleen was of normal volume, homogeneous and without focal changes or uptake of FDG. The bone marrow had no signs of lymphomatous infiltration. Overall, the PET/CT findings were interpreted as consistent with Mazabraud's syndrome.\nAfter the scans, the intramuscular mass located in the proximal right adductor magnus muscle was excised. It had well-defined borders and measured 6 × 5 × 3 cm. Histological examination of the lesion supported the radiological diagnosis of myxoma (Fig. ).