Klin Onkol 2026; 39(3): 169-183. DOI: 10.48095/ccko2026169.
Background: Diseases caused by immune system disorders fall under the care of every medical specialty. In hematology, these are diseases caused by autoantibodies, several autoinflammatory diseases (Schnitzler syndrome and VEXAS syndrome), as well as immune disorder-induced diseases presenting with systemic inflammatory reactions and lymphadenopathy. In the 5th edition of the WHO classification, these diseases are categorized under the chapter “Tumour-like lesions with B-cell predominance”, which includes Castleman disease (CD). Objective: This paper provides an overview of information on CD from the perspective of the years 2025 and 2026. In patients with unicentric CD (UCD), associations with paraneoplastic pemphigus or obliterative bronchiolitis have been described in rare cases. Prognostically unfavorable is the transformation of UCD into a follicular dendritic cell sarcoma. In cases of multicentric CD (MCD), the etiology is exceptionally identified as an infection with human herpesvirus 8. In rare cases of MCD combined with POEMS syndrome, the etiology is considered to be a monoclonal gammopathy. In most cases of MCD, none of the aforementioned etiologies are demonstrated, and these forms of MCD are referred to as idiopathic MCD (iMCD). The most aggressive form of iMCD is called iMCD-TAFRO, and its course resembles a cytokine storm. The form with the lowest aggressiveness was defined recently – idiopathic plasmacytic lymphadenopathy (iMCD-IPL) with a high concentration of polyclonal immunoglobulins and a higher concentration of the IgG4 subclass of immunoglobulins. Between these two extreme forms lies the majority of cases falling into the iMCD-NOS (not otherwise specified) category. Differences in the aggressiveness are caused by differences in etiopathogenesis. The text presents recent criteria for these diseases, information on symptoms, diagnosis, and prognosis. Conclusion: In MCD, suspicion must be raised in individuals with a systemic inflammatory response and lymphadenopathy after ruling out autoimmune, malignant, and infectious etiologies. Diagnosis of CD is clinico-pathological, meaning it arises based on the exchange of information between the clinician, who must suspect the disease, and the pathologist, who examines the histomorphological findings while taking into account the information provided by the clinicians.