Navigating Rarity: Extranodal Presentation of Castleman Disease

Castleman disease (CD) is a rare lymphoproliferative disorder, originally described by Dr. Benjamin Castleman, characterized predominantly by enlarged mediastinal lymph nodes with unknown etiology. While it commonly affects mediastinal lymph nodes, occurrences in neck lymph nodes are less frequent, and presentation in the extremities is exceptionally rare. This report presents a case of a 55-year-old female with a 15-year history of a solitary swelling in her right arm. The swelling was initially painful but later the pain subsided gradually.