Exertional Chest Pain and Dyspnea From Hyperviscosity Syndrome Related to Marginal Zone Lymphoma.

Hyperviscosity syndrome is usually seen in Waldenstrom macroglobulinemia with the serum viscosity > 4 cP. It commonly manifests as skin or mucosal bleeding, visual abnormalities and neurological symptoms. We describe a case of a 65-year-old man, who presented with chronic exertional chest pain and dyspnea without other manifestation and had hyperviscosity syndrome related to marginal zone lymphoma (MZL) even with a marginally elevated plasma viscosity. The symptoms resolved after initiation of chemotherapy. This case illustrates that MZL can cause hyperviscosity syndrome, which can manifest with cardiopulmonary symptoms without other clinical features even at a marginally elevated plasma viscosity. Atypical cases of hyperviscosity syndrome can, thus, present diagnostic challenges and require a high index of suspicion.