The discovery that medical treatments can inadvertently seed Alzheimer's disease challenges fundamental assumptions about how this devastating condition spreads. Four men who received contaminated cadaveric growth hormone as children developed early-onset dementia decades later, with one autopsy revealing severe Alzheimer's pathology at just 57 years old. The UK National Prion Clinic documented these cases between patients aged 47-60, all showing prominent language deficits characteristic of frontotemporal presentations. Crucially, postmortem examination of one patient revealed both classic amyloid-beta plaques and severe tau tangles - the twin hallmarks of Alzheimer's disease. This represents the clearest evidence yet that Alzheimer's pathology can be transmitted through contaminated biological materials, similar to prion diseases. The contaminated growth hormone contained amyloid-beta seeds that appeared to initiate a cascade of neurodegeneration 30-40 years after childhood exposure. These findings build on earlier reports of iatrogenic cerebral amyloid angiopathy, but demonstrate that transmission can progress to full Alzheimer's pathology including tauopathy. The clinical presentation differed from typical late-onset Alzheimer's, with language problems predominating rather than memory loss. This research fundamentally alters our understanding of Alzheimer's transmission mechanisms and raises urgent questions about historical medical procedures involving biological materials. While the contaminated hormone preparations were discontinued decades ago, the implications for understanding Alzheimer's spread through surgical instruments, blood products, or other medical interventions remain profound and largely unexplored.