Augsburg, Lukasz

Gielen, Jan

Vanhoenacker, Filip

English

Ghent University Academic Bibliography

Case 14477 McCune Albright Syndrome (MAS) - polyostotic fibrousdysplasiaLukasz Augsburg , Filip M. Vanhoenacker , Jan Gielen1 1, 2, 3 11. University Hospital Antwerp, Department of Radiology, University Hospital Antwerp;Wilrijkstraat, 10, B- 2650 Antwerp, Belgium; Email:filip.vanhoenacker@telenet.be2. AZ Sint-Maarten Duffel-Mechelen, Department of Radiology; Leopoldstraat 2, 2800 Mechelen,Belgium3. Faculty of Medicine and Health Sciences, Ghent University, Belgium University Hospital Antwerp  Musculoskeletal System Section: 2017, Mar. 29 Published: 15 year(s), malePatient:Clinical HistoryA 15-year-old boy presented to the pediatrician with precocious puberty, hyperthyroidism,hyperprolactinemia and large, asymmetric head.Inspection of the skin showed café-au-lait" spots located mainly on the back (Fig. 1) en left buttock.Imaging FindingsConventional radiography (CR) showed multiples bone lesions with a ground glass appearance inboth femurs (Fig. 2, Fig. 3), left humerus (Fig. 4), right tibia and right talus (Fig. 5, Fig. 6). Bonescintigraphy showed multifocal tracer uptake in the axial and appendicular skeleton suggestingactive osteoblastic activity (Fig. 7).Magnetic Resonance Imaging (MRI) of the brain showed asymmetric expansion of the calvaria andfacial bones with significant bone thickening. Lesions showed predominantly low, slightlyinhomogeneous signal intensity on all pulse sequences (Fig.8, Fig.9, Fig. 10). The brain was normal(Fig. 8, Fig. 9). The orbits were small. (Fig. 10). However, there was no compression of the opticnerve (Fig. 10).DiscussionBased on the combination of clinical and imaging findings, the diagnosis of McCune-Albright syndrome (MAS) was made.MAS is a genetic disorder characterized by a typical triad of symptoms: polyostotic fibrousdysplasia (FD), skin pigmentation (café-au-lait spots) and endocrinological disorders [1]. Gonadaldysfunction is considered to be the most common endocrine defect in females, resulting inprecocious puberty and vaginal bleeding. However, Cushing syndrome, pituitary adenomas andhyperthyroidism are also reported [2]. MAS develops from activation of a post-zygotic, sporadic orsomatic mutation of the GNAS1 gene with different clinical manifestations [3]. Affected childrenusually present with skeletal deformities and short stature, resulting from premature closure of theepiphyses. FD is a tumor-like condition of the bone. Histologically it corresponds to immature bone withdelicate trabeculae and interspersed fibrous matrix [4]. This makes the bone more prone tomicrofractures, repetitive remodelling and subsequent deformation [5]. FD associated with MASusually affects multiples bones and leads more frequently to complications such as fractures,skeletal deformities or limb-length discrepancies. It affects most commonly the femora, tibiae,pelvis, skull and ribs. Imaging features of FD may vary from either completely radiolucent lesions,sclerotic delineated radiolucent lesions or lesions with a ground-glass matrix appearance. In case ofdisease progression, bowing of the proximal femora (coxa vara) may occur due to multiple fracturesen repetitive remodelling, resulting in the so-called Sheppard's crook deformity. [4, 6]. Conventional radiography (CR) is usually sufficient to make a reliable diagnosis. Bone scintigraphy may reveal increased osteoblastic activity in affected bones. It is particularlyuseful to assess multifocality. Computed tomography (CT) is usually not mandatory, but may be used to evaluate the preciseextent of FD and potential compression of adjacent structures in complex anatomical structuressuch as the facial bones, skull base and the axial skeleton. However, due to high radiation dose, theuse of CT should be considered with caution. Particularly in the pediatric population, MRI is the preferred technique for evaluation of the lesionextent in the skull bones. Bone expansion may cause compression of adjacent structures, such as theoptic nerve, resulting in visual disturbances. Osteotomy of the involved bones should be consideredin this scenario.Malignant transformation of bone lesions is rare.Paget's disease may appear similar on imaging but is seen in older patients. Association of FD andintramuscular myxoma is known as Mazabraud syndrome.Final DiagnosisPolyostotic fibrous dysplasia related to McCune-Albright SyndromeDifferential Diagnosis ListMazabraud syndrome, Sporadic fibrous dysplasia, Paget's diseaseFiguresFigure 1 Café au lait spots on the back of the patient.Irregularly delineated café-au-lait spots, resembling the coast of Maine in the United Statesof America. © Lukasz Augsburg, UZA, Antwerpen Area of Interest: Musculoskeletal system;  Imaging Technique: Plain radiographic studies;  Procedure: Education;  Special Focus: Congenital; Figure 2 Conventional radiography of the right femur (AP projection)Conventional radiography of the right femur (AP projection) shows a slightly expansilelesion (asterisk) in the proximal diaphysis with a ground-glass appearance and widening ofthe medullary cavity. Note subtle deformity of the hip (arrows). © Augsburg L, Department of Radiology, UZA, Antwerp, Belgium Area of Interest: Musculoskeletal bone;  Imaging Technique: Conventional radiography;  Procedure: Education;  Special Focus: Congenital; Figure 3 Conventional radiography of the left femur (AP projection)Conventional radiography of the left femur (AP projection) shows a ground-glass lesion inthe proximal diaphysis. Note also more subtle lesions in the middle and distal diaphysis(arrowheads). Note slight deformity of the femoral diaphysis. © Augsburg L, Department of Radiology, UZA, Antwerp, Belgium Area of Interest: Musculoskeletal bone;  Imaging Technique: Conventional radiography;  Procedure: Education;  Special Focus: Congenital; Figure 4 Conventional radiography of the right humerus (AP projection)Conventional radiography of the left humerus (AP projection) shows bone expansion of theproximal diaphysis of the left humerus with homogeneous ground-glass matrix (arrows).Note sclerotic teeth-like border with normal proximal metaphysis (arrowheads). © Augsburg L, Department of Radiology, UZA, Antwerp, Belgium Area of Interest: Musculoskeletal bone;  Imaging Technique: Conventional radiography;  Procedure: Education;  Special Focus: Congenital; Figure 5 Conventional radiography of the right foot (AP projection)Conventional radiography of the right foot (AP projection) depicts a focal radiolucent lesionwith sclerotic margin in the talar head (arrows). Note also lesions with ground-glass aspect inthe metatarsals (thick open arrows). © Augsburg L, Department of Radiology, UZA, Antwerp, Belgium Area of Interest: Musculoskeletal bone;  Imaging Technique: Conventional radiography;  Procedure: Education;  Special Focus: Congenital; Figure 6 Conventional radiography of the right foot (oblique projection)Conventional radiography of the right foot (oblique projection) depicts the ground-glassappearance in the talar body and neck (asterisk) and deformity of the head (arrowheads). © Augsburg L, Department of Radiology, UZA, Antwerp, Belgium Area of Interest: Musculoskeletal bone;  Imaging Technique: Conventional radiography;  Procedure: Education;  Special Focus: Congenital; Figure 7 Bone scintigraphyBone scintigraphy. Anterior (a) and posterior (b) projection show increased osteoblasticactivity in de skull, ribs, pelvis, left humerus, both femora, right tibia and talus. © Augsburg L, Department of Radiology, UZA, Antwerp, Belgium Area of Interest: Musculoskeletal bone;  Imaging Technique: SPECT;  Procedure: Education;  Special Focus: Metabolic disorders; Figure 8 Magnetic resonance (MR) of the brainMR of the brain. Axial T2-weighted images (a), FLAIR images (b). MR shows marked butasymmetrical thickening of the calvaria. Although the lesions are slightly inhomogeneous,the overall appearance is of predominant low signal. © Augsburg L, Department of Radiology, UZA, Antwerp, Belgium Area of Interest: Musculoskeletal joint;  Imaging Technique: MR;  Procedure: Education;  Special Focus: Congenital; Figure 9 Magnetic resonance (MR) of the brainMR of the brain. The mid-sagittal T2- weighted image demonstrate marked thickening offrontal-, occipital-, sphenoid bone and clivus. Intracranial structures are normal. © Augsburg L, Department of Radiology, UZA, Antwerp, Belgium Area of Interest: Musculoskeletal bone;  Imaging Technique: MR;  Procedure: Education;  Special Focus: Congenital; Figure 10 Magnetic resonance (MR) of the brainMR of the brain. The axial T2 weighted image (a) show narrowing of the orbit. There is nodefinite compression of the optic nerve (arrow) on the coronal image (b). © Augsburg L, Department of Radiology, UZA, Antwerp, Belgium Area of Interest: Musculoskeletal bone;  Imaging Technique: MR;  Procedure: Education;  Special Focus: Congenital; References[1] Rao S, Colaco MP, Desai MP (2003) McCune Albright Syndrome (MCAS): a case series IndianPediatr. 40(1):29-35.[2] Rubio NI, Nader Sh, Brosnan PG (2006) McCune Albright syndrome: case report and review ofliterature Int J Endocrinol Metab. 4(3):167-75[3] Diaz A, Danon M, Crawford J (2007) McCune-Albright syndrome and disorders due toactivating mutations of GNAS J Pediatr Endocrinol Metab. 20(8):853-80[4] Xavier SP, Ribeiro MC, Sicchieri LG, Brentegani LG, Lacerda SA (2008) Clinical, microscopic,and imaging findings associated to McCune-Albright syndrome: A report of two cases Braz Dent J.19: 165 - 170.[5] Martin-Carreras T, Sanchez E, Bancroft LW (2014) Polyostotic fibrous dysplasia OrthopedicsNov 1. 37(11):722-82[6] Medow JE, Agrawal BM, Resnick DK (2007) Polyostotic fibrous dysplasia of the cervicalspine: case report and review of the literature Spine J. 7: 712 - 715CitationLukasz Augsburg , Filip M. Vanhoenacker , Jan Gielen1 1, 2, 3 11. University Hospital Antwerp, Department of Radiology, University Hospital Antwerp;Wilrijkstraat, 10, B- 2650 Antwerp, Belgium; Email:filip.vanhoenacker@telenet.be2. AZ Sint-Maarten Duffel-Mechelen, Department of Radiology; Leopoldstraat 2, 2800 Mechelen,Belgium3. Faculty of Medicine and Health Sciences, Ghent University, Belgium (2017, Mar. 29)  McCune Albright Syndrome (MAS) - polyostotic fibrous dysplasia {Online}URL: http://www.eurorad.org/case.php?id=14477

McCune Albright Syndrome (MAS) : polyostotic fibrous dysplasia

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McCune Albright Syndrome (MAS) : polyostotic fibrous dysplasia

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