Scleromyxedema is a rare disorder of connective tissue with unknown etiology. Its manifestation includes a generalized mucin deposition, which is frequently associated with paraproteinemia. The course of scleromyxedema is progressive and often lethal. As a result of its poorly understood pathogenesis, there is no causative treatment option. The efficacy of cytoreductive agents and autologous stem cell transplantation has been reported, but so far allografting as a treatment option has not yet been documented. Herein, we report on a patient with severe neurologic involvement and refractory course attaining durable remission after receiving an allogeneic hematopoietic cell transplant from an human leukocyte antigen-matched sibling. This case not only illustrates a potential new treatment option for selected patients, but also provides insights into the pathogenesis of this rare disease.