AbstractTransient myeloproliferative disorder (TMD) is experienced by approximately 10% of neonates with Down syndrome (DS). Most TMD is asymptomatic and the patients undergo spontaneous remission within a few months. However, some cases are fatal because of systemic organ dysfunctions including hepatic fibrosis. Some cytokines such as platelet‐derived growth factor (PDGF) may be involved in the development of hepatic fibrosis in TMD. The report describes a fatal case of TMD accompanying DS. The patient presented with pulmonary hypertension and hepatic failure. An autopsy disclosed severe fibrosis in the lung, liver, kidney and pancreas. Immunohistochemical analysis revealed high expression of PDGF receptor β in the severe fibrotic areas of the fibrotic tissues. A real‐time polymerase chain reaction (PCR) analysis demonstrated the expression of PDGFα and PDGFβ in the peripheral blood samples of the patient. The finding indicates that the PDGF pathway may play an important role in the fibrosis of several organs in patients with TMD.