Progressive vertebral fusion in a girl with spinal enchondromatosis

Dysmorphic facies and diffuse posterior spine ankylosis in a patient with unusual form of spondyloenchondrodysplasia (Spranger type IV)

We describe a male patient, who was seen for the first time at the age of 8 years because of short trunk dwarfism. Spine radiographs showed platyspondyly with irregular areas of increased and decreased mineralization (irregular spotted appearance within lytic lesions located along the posterior vertebral bodies of the entire spine). Skeletal survey showed no enchondromatous lesions of the short/long tubular bones. At the age of 17, progressive spine stiffness associated with stooping posture developed. 3DCT scanning showed pathological transformation of the spinal enchondromas into generalized ossification and thickening of the posterior vertebral elements (vertebral laminae, supraspinal, and interspinal ligaments, respectively) causing effectively the development of a diffuse posterior spinal ankylosis. We report what might be a unique subtype of spondyloenchondrodysplasia (Spranger type IV).

Achondroplasia manifesting as enchondromatosis and ossification of the spinal ligaments: a case report

Introduction

A girl presented with achondroplasia manifested as mild knee pain associated with stiffness of her back. A skeletal survey showed enchondroma-like metaphyseal dysplasia and ossification of the spinal ligaments. Magnetic resonance imaging of the spine further clarified the pathological composites.

Case presentation

A 7-year-old girl presented with the classical phenotypic features of achondroplasia. Radiographic documentation showed the co-existence of metaphyseal enchondromatosis and development of spinal bony ankylosis. Magnetic resonance imaging showed extensive ossification of the anterior and posterior spinal ligaments. Additional features revealed by magnetic resonance imaging included calcification of the peripheral vertebral bodies associated with anterior end-plate irregularities.

Conclusion

Enchondromas are metabolically active and may continue to grow and evolve throughout the patient's lifetime; thus, progressive calcification over a period of years is not unusual. Ossification of the spinal ligaments has a specific site of predilection and often occurs in combination with senile ankylosing vertebral hyperostosis. Nevertheless, ossification of the spinal ligaments has been encountered in children with syndromic malformation complex. It is a multifactorial disease in which complex genetic and environmental factors interact, potentially leading to chronic pressure on the spinal cord and nerve roots with subsequent development of myeloradiculopathy. Our patient presented with a combination of achondroplasia, enchondroma-like metaphyseal dysplasia and calcification of the spinal ligaments. We suggest that the development of heterotopic bone formation along the spinal ligaments had occurred through an abnormal ossified enchondral mechanism. We postulate that ossification of the spinal ligaments and metaphyseal enchondromatous changes are related to each other and represent impaired terminal differentiation of chondrocytes in this particular case. Standard radiographic examination showed spinal bony ankylosis only. The pathological composites of the vertebrae have been clarified using scanning technology. Extensive spinal ligament ossification associated with calcification of the peripheral vertebral bodies and anterior end-plate irregularities were notable. We report what may be a novel spinal and extraspinal malformation complex in a girl with achondroplasia.