Castleman disease (CD) is a lymphoproliferative disorder and rarely affects ocular tissue. This study aimed to report a case of hypertensive choroidopathy in a patient with Castleman's disease associated with malignant hypertension. A 39-year-old man visited his local physician with fever, systemic edema, and multiple lymphadenopathies. An inguinal lymph node biopsy indicated CD. One month after the biopsy, the patient noted a blurring of vision. At the time of the initial examination at our hospital, his best-corrected visual acuity (BCVA) was 20/20 in both eyes but there were bilateral multiple Elschnig spots and sprinter hemorrhage at the fundus. Swept-source optical coherence tomography showed intra-retinal fluid, and serous retinal detachment (SRD). Fluorescein angiography revealed multiple punctate hyper fluorescences and indocyanine green angiography showed choroidopathy with increased vascular permeability. A general examination revealed symptoms of cardiac failure and multiple lymphadenopathies. Malignant hypertension with acute glomerulonephritis was diagnosed after a renal biopsy. After antihypertensive treatment, his blood pressure (BP) improved, and the SRD and choroidopathy promptly resolved. Presently, the patient is being followed up without complications. We report a case of hypertensive choroidopathy in a patient with CD associated with malignant hypertension. As a severe elevation in BP can damage choroidal vasculature and lead to vision loss, careful observation and active treatment are necessary.