Castleman disease as the great mimicker: the role of complex morpho-pathological evaluation.

Castleman disease (CD) is a group of lymphoproliferative disorders characterized by abnormal enlargement of lymph nodes (LNs) and a wide range of symptoms. Only a few cases are found in the head and neck. Based on clinical presentation and evolution, the disease can be classified into two main subtypes: unicentric CD (UCD), characterized by the enlargement of a single LN or a single LN chain, and multicentric CD (MCD), characterized by the involvement of multiple LNs and regions, with more important systemic symptoms and a poor prognosis. CD is also known as "the great mimicker" and can be easily misdiagnosed, sharing similar clinical and imaging characteristics with other pathologies, mainly when it is found in the neck. A histopathological (HP) and immunohistochemical (IHC) correlation is essential in these cases to accurately diagnose and establish the proper treatment plan. In light of this, we present a rare case of a 15-year-old young female with a slowly expanding, isolated supraclavicular mass. An excisional biopsy was performed, and the results confirmed the presence of CD, hyaline-vascular type. As of this writing, there was no evidence of recurrence or new enlarged LNs. We also review CD's clinical and HP features and the diagnostic and treatment challenges it poses.