A summary of common clinical, laboratory, and histopathological features on the spectrum of patients with UCD to those with OligoCD and with iMCD. Patients demonstrate differences in lymphadenopathy, histopathology, laboratory and clinical abnormalities, and degree of inflammation. The patients with the least severe disease typically have UCD, and the most severe cases are typically iMCD-TAFRO. Severity of symptoms along this spectrum should be considered when making a diagnosis. HV, hyaline vascular; hyperV, hypervascular; PC, plasmacytic.