Hyperhomocysteinemia-related lung disease and hemolytic anemia with bone marrow features masquerading as myelodysplasia.

Hyperhomocysteinemia is linked to TMA-related clinical symptoms such as apparent thromboembolism, microangiopathic hemolytic anemia (MAHA), and various types of end-organ damage due to microvascular thrombi; this is because high plasma levels of homocysteine impair the vascular endothelium. However, the association between hyperhomocysteinemia and pulmonary involvement is unclear. Here, we describe a 63-year-old male who was hospitalized with respiratory failure and MAHA with MDS-like features in the bone marrow. Plasma homocysteine levels were elevated significantly with 199.4 µmol/L (reference: 6.3-18.9) due to a homozygous (T/T) polymorphism for the 677C>T mutation within the MTHFR gene associated with chronic alcoholism-induced folate deficiency. Pulmonary lesions showed ground-glass opacity and there was pleural effusion. The patient was managed successfully with a combination of folate/mecobalamin supplementation, plasma exchange, and a methylprednisolone pulse, followed by oral prednisolone. Clinical symptoms, lung disease, MAHA, and bone marrow abnormalities improved as plasma homocysteine levels normalized.