Plexiform neurofibromas (PNs) are common and potentially debilitating complications of
neurofibromatosis 1 (NF1). These benign
nerve-sheath tumors are associated with significant
pain and morbidity because they compress vital structures. The
mammalian target of rapamycin (mTOR) pathway is a major mediator involved in
tumor growth in NF1. We present 3 cases of patients with NF1, aged 8, 16, and 17 years, followed for inoperable and symptomatic PNs; patients received
sirolimus for life-threatening and painful
neurofibromas after multidisciplinary consultation. Epidemiologic, clinical, and radiologic data were retrospectively collected. The volume of PNs did not differ between baseline and 12-month follow-up and
pain was alleviated, with withdrawal of
analgesics in 2 cases at 6 months, and significantly decreased for the third case.
Sirolimus for inoperable symptomatic PNs in patients with NF1 permitted stabilization of mass and produced unpredictable and important alleviation of
pain in all cases with good tolerance. This treatment was proposed in extreme cases, in absence of therapeutic alternatives, after multidisciplinary consensus. The mTOR pathway may be both a major mediator of NF1
tumor growth and regulator of nociceptor sensitivity.
mTOR inhibitors clinically used as anticancer and
immunosuppressant drugs could be a potential treatment of
chronic pain.