Figure 1
Teaching Case
SectionChest imaging
Case TypeClinical Cases
AuthorsFabiano S, Ciancarella P, Bindi A, Funel V, Liberto V, Simonetti G
Connected authors
33 years, male
A 33-year-old male patient with a previous diagnosis of McCune-Albright syndrome (MAS) presented with respiratory distress that limited his daily activities. His medical history included hyperprolactinaemia due to pituitary adenoma, several previous fractures of the extremities and reconstructive surgery for craniofacial deformities.
Respiratory failure due to restrictive lung disease in MAS
Simple polyostotic fibrous dysplasia
Neurofibromatosis type I
Enchondromatosis
Paget disease
Physical examination showed the characteristic signs of MAS with extensive facial and extremities bone deformities, cafè au lait cutaneous spots, walking difficulty and dyspnoea.
Blood gas analysis demonstrated a mild respiratory acidosis, hypoxaemia and hypercapnia.
Cardiological evaluation presented a chronic pulmonary heart disease with dilatation of right cardiac ventricle and atrium, right ventricular dysfunction and pulmonary artery hypertension.
Chest plain radiography showed severe deformity of the chest wall due to abnormal proliferation of soft tissues with the involvement of ribs, both clavicles and humerus, enlargement of cardiac silhouette with severe decrease of lung volumes.
A computed tomography (CT) examination with multiplanar and volume rendering reconstructions demonstrated diffuse developmental anomalies of chest bone components, characterized by abnormal hypodense fibrous tissue associated with diffuse thinning of bone cortex, which compressed the lung parenchyma and reduced its volume as a result. Pleural effusion was also present at the bases. No lung consolidations were seen.
Blood gas analysis demonstrated a mild respiratory acidosis, hypoxaemia and hypercapnia.
Cardiological evaluation presented a chronic pulmonary heart disease with dilatation of right cardiac ventricle and atrium, right ventricular dysfunction and pulmonary artery hypertension.
Chest plain radiography showed severe deformity of the chest wall due to abnormal proliferation of soft tissues with the involvement of ribs, both clavicles and humerus, enlargement of cardiac silhouette with severe decrease of lung volumes.
A computed tomography (CT) examination with multiplanar and volume rendering reconstructions demonstrated diffuse developmental anomalies of chest bone components, characterized by abnormal hypodense fibrous tissue associated with diffuse thinning of bone cortex, which compressed the lung parenchyma and reduced its volume as a result. Pleural effusion was also present at the bases. No lung consolidations were seen.
MAS is a genetic, non-inheritable disease characterized by the association of polyostotic fibrous dysplasia (FD), cafè au lait spots (typically located on the same side as the bone lesions) and endocrine dysfunctions [1, 2]. It represents less than 5% of patients with FD, while the monostotic form represents 60% of patients with FD. The prevalence of FD and MAS is unknown, but it has been estimated around 1 in 30,000. MAS is ten times more common in women [3].
MAS is caused by a somatic postzygotic mis-sense mutation in the GNAS1 gene encoding the subunit of the signal-transducing G-protein.
This mutation generates autonomous fibroblast proliferation, defective osteoblast differentiation, increased bone resorption and hormonal hypersecretion, responsible for corresponding clinical features [4].
Endocrine tumours may coexist and include pituitary, adrenal, testicular, thyroid localizations [5].
Bone involvement in MAS is typically polyostotic. Upper and lower extremities are commonly affected together with pelvis and craniofacial locations, but every bone segment may be involved. Lesions expand typically from the medulla to the cortex and the surrounding cortical bone is thinned. Calcifications can be observed if a nucleus of cartilage is present.
Radiological findings depend on the degree of ossification of bone lesions, showing an increased bone radiolucency in plain radiography, well demonstrated with CT as a mild density abnormal tissue replacing bone marrow, associated with reduction of bone cortex.
The deep remodelling of woven bone and the development of abnormal tissue with poor mechanical strength cause several complications. Bone pain, usually spontaneous or after a mild trauma, often represents the first symptom of FD and MAS and reveals the presence of a pathological complete or incomplete fracture.
Malignant degeneration is rare. The most common malignancy, in order of frequency, is osteosarcoma followed by fibrosarcoma and chondrosarcoma [6, 7]. In these cases CT and MRI are necessary to confirm clinical diagnosis.
Medical therapy includes the use of bisphosphonates to improve function, decrease pain, and lower fracture risk. Surgery is indicated for confirmatory biopsy, correction of bone deformity, prevention of pathologic fracture, and eradication of symptomatic lesions [8, 9].
The involvement of ribs and chest cage is not rare in patient with MAS, but the development of respiratory failure with a restrictive pattern, pulmonary heart disease and right ventricular failure have been described only in few cases in the literature [10 -12]. In these patients surgical resection should be performed to relieve respiratory failure and improve quality of life [10, 11].
MAS is caused by a somatic postzygotic mis-sense mutation in the GNAS1 gene encoding the subunit of the signal-transducing G-protein.
This mutation generates autonomous fibroblast proliferation, defective osteoblast differentiation, increased bone resorption and hormonal hypersecretion, responsible for corresponding clinical features [4].
Endocrine tumours may coexist and include pituitary, adrenal, testicular, thyroid localizations [5].
Bone involvement in MAS is typically polyostotic. Upper and lower extremities are commonly affected together with pelvis and craniofacial locations, but every bone segment may be involved. Lesions expand typically from the medulla to the cortex and the surrounding cortical bone is thinned. Calcifications can be observed if a nucleus of cartilage is present.
Radiological findings depend on the degree of ossification of bone lesions, showing an increased bone radiolucency in plain radiography, well demonstrated with CT as a mild density abnormal tissue replacing bone marrow, associated with reduction of bone cortex.
The deep remodelling of woven bone and the development of abnormal tissue with poor mechanical strength cause several complications. Bone pain, usually spontaneous or after a mild trauma, often represents the first symptom of FD and MAS and reveals the presence of a pathological complete or incomplete fracture.
Malignant degeneration is rare. The most common malignancy, in order of frequency, is osteosarcoma followed by fibrosarcoma and chondrosarcoma [6, 7]. In these cases CT and MRI are necessary to confirm clinical diagnosis.
Medical therapy includes the use of bisphosphonates to improve function, decrease pain, and lower fracture risk. Surgery is indicated for confirmatory biopsy, correction of bone deformity, prevention of pathologic fracture, and eradication of symptomatic lesions [8, 9].
The involvement of ribs and chest cage is not rare in patient with MAS, but the development of respiratory failure with a restrictive pattern, pulmonary heart disease and right ventricular failure have been described only in few cases in the literature [10 -12]. In these patients surgical resection should be performed to relieve respiratory failure and improve quality of life [10, 11].
References
[1] McCune DJ (1936) Osteitis fibrosa cystica: the case of of a nine year old girl who also exhibits precocious puberty, multiple pigmentations of the skin and hyperthyroidism. American Journal of Diseases of Children 52:743-744
[2] Albright F, Butler AM, Hampton AO & Smith (1937) Syndrome characterized by osteitis fibrosa disseminate, areas of pigmentation and endocrine dysfunction, with precocious puberty in females. The New England Journal of Medicine 216: 727-746
[3] Roland D. Chapurlat, Philippe Orcel (2008) Fibrous dysplasia of bone and McCune–Albright syndrome. Best Practice & Research Clinical Rheumatology 22(1):55-69. (PMID: 18328981)
[4] Kaushik S, Montileone M, Yarlagadda A (2004) Albright\'s Fibrous Dysplasia. Encyclopedia of Endocrine Diseases Pages 147-150
[5] Shenker A, Weinstein LS, Moran A, et al. (1993) Severe endocrine and non endocrine manifestations of the McCune–Albright syndrome associated with activating mutations of stimulatory G protein GS. The Journal of Pediatrics 123:509–518 (PMID: 8410501)
[6] Yabut SM Jr, Kenan S, Sissons HA, Lewis MM (1988) Malignant transformation of fibrous dysplasia: a case report and review of the literature. Clinical Orthopaedics 228:281–289 (PMID: 3277758)
[7] Ruggieri P, Sim FH, Bond JR, Unni KK (1994) Malignancies in fibrous dysplasia. Cancer 73:1411–1424 (PMID: 8111708)
[8] Arabella I. Leet, Michael T. Collins (2007) Current approach to fibrous dysplasia of bone and McCune–Albright syndrome. Journal of Children’s Orthopaedics 1(1): 3–17. (PMID: 19308500)
[9] Matthew R. DiCaprio, William F. Enneking (2005) Fibrous Dysplasia: Pathophysiology, Evaluation, and Treatment. J Bone Joint Surg Am 87(8):1848-1864 (PMID: 16085630)
[10] R Michael King, W Spencer Payne, Snorri Olafsson, Krishnan K Unni (1985) Surgical palliation of respiratory insufficiency secondary to massive exuberant polyostotic fibrous dysplasia of the ribs. Annals Thor Surg 39;185–187 (PMID: 2578778)
[11] O\'Connor B, Collins FJ (2009) The management of chest wall resection in a patient with polyostotic fibrous dysplasia and respiratory failure. J Cardiothorac Vasc Anesth 23(4):518-21 (PMID: 19054694)
[12] Narayan RL, Maldjian PD (2009) Restrictive lung disease and cor pulmonale secondary to polyostotic fibrous dysplasia. Int J Cardiol 131(2):e48-50 (PMID: 17719106)
Case information
| URL: | https://www.eurorad.org/case/11638 |
| DOI: | 10.1594/EURORAD/CASE.11638 |
| ISSN: | 1563-4086 |
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Figure 1
Fabiano S, Department of Radiology, Tor Vergata University, Rome, Italy
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Fabiano S, Department of Radiology, Tor Vergata University, Rome, Italy
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Fabiano S, Department of Radiology, Tor Vergata University, Rome, Italy