The mechanism of UCD is poorly understood. Most published research supports a growth of abnormal immune system cells (neoplasm) as the most likely cause of UCD, but this has not been conclusively demonstrated or fully characterized. Other proposed mechanisms include viral infections and autoimmune processes. Because surgical removal of affected lymph nodes in UCD is typically curative and recurrence is rare, it is believed that the pathologic process is limited to affected lymph nodes. Unlike HHV-8-associated MCD, which is caused by the HHV-8 virus, UCD has not been associated with HHV-8 infection1 When findings typically seen in MCD, such as systemic symptoms and laboratory abnormalities, they are likely related to increased levels of molecules that stimulate the immune system (cytokines), such as interleukin 6 (IL-6). Systemic symptoms and laboratory abnormalities may be associated with the presence of plasmacytic features on microscopic analysis of affected lymph node tissue. There have been no reported cases of UCD transforming into iMCD.
Unicentric Castleman disease
Idiopathic multicentric Castleman disease
Follicular lymphoma
Follicular dendritic cell sarcoma
Progressive nodular histiocytoma
Thymic carcinoma
Marginal zone B-cell lymphoma
Progressive nodular histiocytosis