Imaging findings of mucopolysaccharidoses: a pictorial review

Abstract

IntroductionMucopolysaccharidosis (MPS) represent a heterogeneous group of inheritable lysosomal storage diseases in which the accumulation of undegraded glycosaminoglycans (GAGs) leads to progressive damage of affected tissues. The typical symptoms include organomegaly, dysostosis multiplex, mental retardation and developmental delay. Definitive diagnosis is usually possible through enzymatic assays of the defective enzyme in cultured fibroblasts or leukocytes.Imaging findingsRadiological and neuroradiological findings are reported. The most important neuroradiological features include abnormal signal intensity in the white matter, dilatation of periventricular spaces, widening of cortical sulci, brain atrophy, enlargement of extraventricular spaces and spinal cord compression. With reference to the skeletal system, most important radiological findings include multiplex dysostosis, which is represented by several bone malformations found in the skull, hands, legs, arms and column. The abnormal storage of GAGs leads to liver and spleen enlargement; it also damages cartilage layers and synovial recesses in the joints.ConclusionThe aim of this pictorial essay is to describe the imaging findings of MPS, represented by skeletal and neurological features; skeletal X-ray and MR allow an assessment of the severity of disease, to plan medical and surgical therapy and to evaluate response to treatment.Teaching Points• To describe the imaging findings common to different types of MPS.• To describe multiplex dysostosis encountered in the axial and appendicular skeleton.• To evaluate neuroradiological features of MPS, including brain abnormal signal intensity and atrophy.• To evaluate important otorhinolaryngological problems, such as otitis media and airways obstruction.

Rare cases of classical Hurler-Scheie syndrome

“…Roentgenological examination usually shows 'J' shaped sella turcica, thickened cranial vault, hypoplastic epiphysis, distally curved and shortened diaphysis, notched proximal part of humerus, long and narrow femoral neck, round iliac wings often with inferior tapering, paddle or oar shaped ribs and flattened vertebrae. 10 Dental abnormalities may be present in MPS-I including caries, delayed eruption, high arched palate and open bite are sometimes observed, as depicted in this report.…”

Delayed speech, hyperactivity, and coarse facies: Does Sanfilippo syndrome come to mind?

“…[6] The most common radiological findings are described as dysostosis multiplex. [7] This comprises enlarged skulls thoracolumbar kyphosis, abnormally shaped vertebrae and ribs, spatulate ribs, hypoplastic epiphyses, thickened diaphyses, and bullet-shaped metacarpals.…”

Pathogenesis and treatment of spine disease in the mucopolysaccharidoses

“…Case reports frequently describe the “scalloped” appearance of vertebrae in MPS patients, referring to the pronounced rounded appearance of the peripheral regions of these bones in the lateral and coronal aspects [124, 125]. Post mortem histological examination of vertebral tissue from a 19-year-old MPS VII patient revealed cartilaginous lesions in the peripheral regions, potentially accounting for the scalloped appearance observed radiographically [8].…”