Introduction
Pediatric lymphadenopathy has a broad differential, one of which is progressive transformation of germinal centers (PTGC). PTGC is characterized histologically by the expansion of mantle zone lymphocytes, follicular dendritic cells, and T-cell lymphocytes into germinal centers, resulting in germinal center enlargement and disruption of architectural differentiation in the lymph node (LN).1 The expansion of LN follicles causes clinically apparent LN enlargement. Affected LN may contain epithelioid histiocytes and other cells consistent with infection or granulomatous reactions;1 however, patients with PTGC may have no symptoms other than LN enlargement.2 Nodes affected by PTGC can recur after excisional surgeries. Interestingly, PTGC can precede, occur synchronously, or occur after the diagnosis of lymphomas,3-5 although the association between lymphomas and PTGC remains unclear. While PTGC is a rare diagnosis overall, it has been better described in adults and shows a predominance among young adult males.4 Given that literature describing the clinical and diagnostic features of PTGC in pediatric patients remains limited to small case series,2,6-8 we reviewed pediatric cases of PTGC at our institution across 20 years to add to the data surrounding this diagnostic mystery.