Acalvaria in a patient with neurofibromatosis type-1: Case report

Abstract

INTRODUCTION

Neurofibromatosis type 1 (NF1) is a heterogeneous disorder of autosomal dominant inheritance. It is characterized by neurofibromas, skin and skeletal changes, and multiple organs and systems involvement. Acalvaria is a rare condition of congenital malformation, usually defined by the absence of the flat bones of the skull, adjunct musculature and dura mater. It is a fatal condition and accompanied by other abnormalities in most cases. The most widely accepted theory suggests that acalvaria is a post-neurulation defect in which there would be a change in mesenchymal tissue migrations but normal ectoderm development.

CASE REPORT

We present the case of a patient with NF1 with a report of a convulsive crisis, who, on examination, showed depression in the posterior portion of the skull, facial asymmetry, diffuse fibromatous lesions, Café au lait macules (CALMs), bilateral horizontal nystagmus and left upper limb hyperreflexia. A cystic mass was identified in the posterior region and agenesis of the occipital bone through imaging, characterising acalvaria.

CONCLUSION

Most calvaria defects are often associated with a mass lesion, typically a plexiform neurofibroma, However, the correlation between abnormalities of the lambdoid suture or occipital bone with NF1 is rare. In contrast, total loss of the NF1 gene is likely to be correlated with focal congenital events, as seen in this patient. This case report reinforces the embryonic theory of acalvaria and correlates the possibility of mutations in the NF1 gene.