A patient with Huntington’s disease and long-surviving fetal neural transplants that developed mass lesions

Transplantation of human fetal neural tissue into adult neostriatum is an experimental therapy for Huntington’s disease (HD). Here we describe a patient with HD who received ten intrastriatal human fetal neural transplants and, at one site, an autologous sural nerve co-graft. Although initially clinically stable, she developed worsening asymmetric upper motor neuron symptoms in addition to progression of HD, and ultimately died 121 months post transplantation. Eight neural transplants, up to 2.9 cm, and three ependymal cysts, up to 2.0 cm, were identified. The autologous sural nerve co-graft was found adjacent to the largest mass lesion, which, along with the ependymal cyst, exhibited pronounced mass effect on the internal capsules bilaterally. Grafts were composed of neurons and glia embedded in disorganized neuropil; robust Y chromosome labeling was present in a subset of grafts and cysts. The graft–host border was discrete, and there was no evidence of graft rejection or HD pathologic changes within donor neurons. This report, for the first time, highlights the potential for graft overgrowth in a patient receiving fetal neural transplantation.