Proteus syndrome revealing itself after the treatment of a bilateral subdural haematoma.

Introduction: Hypertrophy of the calvarium has different aetiologies, among them the rare Proteus syndrome.

Case Report: We report here the case of a young girl initially treated for relapsing right then left large chronic subdural haematoma, who progressively developed craniofacial hypertrophy consistent with the diagnosis of Proteus syndrome. Calvarium hypertrophy was shaved and remodelled combining midface advancement, essentially for cosmetic purposes. During the first calvarium remodelling, important bleeding of the bone required large volume of blood replacement. Haemostasis workup revealed platelets aggregation anomalies. Bleeding issues during subsequent surgeries were controlled with tranexamic acid and desmopressin acetate.

Discussion: Other manifestations of Proteus syndrome, such as a right hypertrophy of the face with hypoplasia of its middle third, a pigmented epidermal nevus and asymmetric limbs and scoliosis, appeared progressively over time. Blood and fibroblast phosphatase and tensin homolog mutation was not found.

Conclusion: Literature review of operated patients with Proteus syndrome did not reveal an association with platelets anomalies. A complete haemostasis workup following this unexpected haemorrhagic complication is recommended for this rare pathology.