en Peripheral nervous system Case report <div style="text-align: justify;"><strong>Background and Importance:</strong> Klippel-Tr&eacute;naunay syndrome is a rare congenital condition that rarely affects peripheral nerves. Median nerve involvement at the carpal tunnel level has only been reported on four occasions of this syndrome in the medical literature.<br> <strong>Case Presentation:</strong> A 61-year-old Caucasian female patient with Klippel-Tr&eacute;naunay syndrome presented with a 10-month history of paraesthesia and numbness affecting the median nerve distribution area of her left hand. The clinical and neurophysiological examination confirmed a moderately severe carpal tunnel syndrome that required surgical decompression.<br> <strong>Conclusion:</strong> Pre-operative findings demonstrated diffuse vascular infiltration and engorgement of the median nerve. Flexor tendons had a normal appearance. The patient had a satisfactory post-operative period with full resolution of her symptoms 4 weeks after the procedure. Although peripheral nerves are rarely affected in patients with Klippel-Tr&eacute;naunay syndrome, neurological symptoms could indicate nerve involvement and magnetic resonance imaging (MRI) examination should be considered to further assess the extension of the lesion.</div> Klippel-Trénaunay syndrome, Carpal tunnel Syndrome, Median nerve 161 164 http://irjns.org/browse.php?a_code=A-10-305-1&slc_lang=en&sid=1 Joan Arenas-Prat arenasprat@hotmail.com 10031947532846005998 10031947532846005998 Yes Serveis Mèdics Penedès, Department of Orthopedics, Barcelona, Catalonia, Spain.