Proteus syndrome with sciatic nerve fibrolipomatous hamartoma: an uncommon finding in a rare disease: report of two cases with literature review

Proteus syndrome is an extremely rare condition, characterized by progressive asymmetric overgrowth of multiple body tissues. Here, we present two cases of Proteus syndrome demonstrating typical clinical and radiological features of Proteus syndrome, in addition to an uncommon fibrolipomatous hamartoma of the sciatic nerve. The first case is a 5-year-old girl who presented with seizures. The patient showed facial dysmorphic features, left head enlargement, kyphoscoliosis, asymmetric overgrowth of the right lower limb, right foot drop, and cribriform connective tissue nevi on the right palm and the right sole. Radiological examinations demonstrated left calvarial hyperostosis, dysplasia of the left cerebral hemisphere, dysregulation of the subcutaneous adipose fat of the body, kyphoscoliosis, and lipoma of the filum terminale. CT of both thighs showed asymmetric soft tissue overgrowth of the right thigh, associated with diffuse enlargement and fatty infiltration of the right sciatic nerve starting from the upper thigh, down to its bifurcation into the tibial and common peroneal nerves. The second case is an 18-year-old girl who presented with left conductive deafness. The patient showed facial dysmorphic features, right head enlargement, asymmetric overgrowth of the right upper limb, kyphoscoliosis, left foot drop, and cribriform connective tissue nevi on the nose and the left foot. Radiological examinations demonstrated right calvarial hyperostosis, left external auditory canal hyperostosis and stenosis, and kyphoscoliosis. CT and MRI of both thighs showed diffuse enlargement of the left sciatic nerve starting from the upper thigh down to the mid-thigh and showing interfascicular adipose tissue proliferation, giving the typical features of nerve lipomatosis.