Epidemiology of Castleman disease associated with AA amyloidosis: description of 2 new cases and literature review.

HHV8-negative Castleman disease (CD) is classified as hyaline vascular (HV) type, or mixed or plasma cell (PC) types. It may present as multicentric CD (MCD) or unicentric CD (UCD). CD is a rare cause of AA amyloidosis (AAA). We aimed to report the main features of CD with secondary AAA through a description of new cases and a systematic literature review. New cases were identified from the French National Reference Center for AAA. A systematic literature review was performed to identify HHV8-negative CD cases associated with AAA. Thirty-seven patients were analysed, consisting of two new cases and 35 from literature. Twenty-three had UCD and 14 had MCD. PC was the main histologic subtype ( = 25; 68%) in both UCD and MCD patients. Surgical excision of UCD was performed in 21 patients (91%) with a favourable outcome, except for four patients (19%). Clinical and biologic remission was achieved in six patients with MCD (43%), all of whom were treated with anti-interleukin-6 (IL-6) therapy. AAA is a rare complication of CD, namely idiopathic MCD and UCD presenting with the PC histologic subtype. Surgical excision of UCD should be the first-line treatment whenever possible, while anti-IL-6 therapies seem effective for MCD.