Imaging of Marfans syndrome

Clinical History

18-year-old male patient with a h/o breathlessness for 6 months was referred to us for chest X-ray. There was also a history of chronic lower back pain. In addition to breathlessness and low back pain the patient also had a history of numbness in both legs.

Imaging Findings

X-ray chest showed levoscoliosis (Fig. 1). X-ray of both hands revealed long metacarpals (Metacarpal index 9.4) s/o arachnodactyly (Fig. 2). MRI spine showed ductal ectasia which is defined as ballooning or widening of the dural sac (Fig. 3). Computed Tomography chest was done which showed annuloaortic ectasia with effacement of sino-tubular junction. There was also dilatation of the proximal aorta. There was no evidence of aortic dissection or coarctation (Fig. 4).

Discussion

The incidence of Marfan syndrome (MS) is 2-3 per 10000 persons [1]. It is a systemic disorder of connective tissue in which there are mutations in FBN1 gene on chromosome 15 [2]. These mutations are responsible for the production of defective extracellular matrix protein fibrillin 1. The major manifestations of Marfan syndrome involve cardiac, ocular and musculoskeletal systems. The cardiac manifestations may occur in the form of aortic root dilatation, aortic regurgitation, mitral valve prolapse and aortic dissection [3]. The musculoskeletal manifestations include tall and slender individuals having arachnodactyly, dolichostenomelia, scoliosis, pectus carinatum or pectus excavatum [4]. The ocular manifestations of MS include glaucoma, uveitis, cataract, retinal detachment and dislocation of lense [5]. Given the widespread involvement, MS cannot be diagnosed on the basis of any one pathognomic feature. Rather, the diagnosis is based upon various clinical abnormalities. Modified Ghent criterion is used for the diagnosis of Marfan syndrome. It is a scoring system where the clinical abnormalities are given certain scores and depending upon the scores a patient is labelled to be having Marfan syndrome. In this scoring system more weightage is given to ectopia lentis and aortic root dilatation [6]. Other clinical signs which are included in Ghent criteria include Walker sign, Steinberg sign, pectus abnormality, crowding of teeth and characteristic facial features [7]. The investigations include molecular genetic testing to identify defective genes as well as to screen family members of a person affected with Marfan syndrome. Imaging studies may include chest radiograph which may show scoliosis [Fig. 1], pectus excavatum or pectus carinatum. X-ray pelvis may show hip dislocation. X-ray of hands may be used to find out metacarpal index which is usually calculated by obtaining the average of the ratios of length divided by width of second to fifth metacarpals (Fig. 2). Alhough metacarpal index is a poor indicator of Marfan, it becomes significant if other features of Marfan syndrome are present [8]. MRI spine may show dural ectasia i.e. enlargement of thecal sac (Fig. 3). CT chest may show aortic root dilatation (Fig. 4). 2D Echo may demonstrate presence of mitral valve prolaps or aortic regurgitation. There is no specific treatment of Marfan syndrome. Treatment is aimed at correction of deformities and prevention of development of complications [9, 10].

Differential Diagnosis List

Final Diagnosis

Marfan syndrome

URL:	https://www.eurorad.org/case/13918
DOI:	10.1594/EURORAD/CASE.13918
ISSN:	1563-4086