COVID-19 in a Hairy Cell Leukemia Patient: A Rare Case Report.

The detailed clinical course of coronavirus disease 2019 (COVID-19) in patients with hairy cell leukemia (HCL) is rarely reported. We report the first case of HCL diagnosed with prolonged pancytopenia after COVID-19 infection in Japan. We describe the case of a 56-year-old man who was diagnosed with COVID-19. Computed tomography revealed ground-glass opacities in the bilateral lung lobes as well as splenomegaly. Remdesivir and dexamethasone were administered for the treatment of COVID-19. Since the pancytopenia persisted, bone marrow examination was performed, and he was diagnosed with HCL. Although pancytopenia can occur with COVID-19 alone, clinicians should be alerted regarding the presence of hematologic malignancies in patients in whom pancytopenia persists after COVID-19 treatment or in those with splenomegaly. Further, the condition of all previously reported patients with COVID-19 associated with HCL was severe enough to require mechanical ventilation. This is the first case in which the disease was not severe. The interleukin-6 (IL-6) level was lower in this case than in previous cases, suggesting that racial differences in IL-6 production may have contributed to COVID-19 severity.