Objective: To determine the frequency of thymic involvement in Langerhans' cell histiocytosis and describe its imaging appearance before and after treatment.
Materials and methods: A retrospective review of the radiology and clinical records of all patients diagnosed with Langerhans' cell histiocytosis at DeVos Children's Hospital between 1992 and 1998.
Results: Of the 14 patients diagnosed with Langerhans' cell histiocytosis, 7 demonstrated multisystem involvement. The thymus was involved in 5 of 7 patients. The thymus was enlarged in 5; thymic contours were nodular/lobulated in 2; cystic changes were noted in 4; and dystrophic vascular-appearing calcifications were seen in 1. In all cases, findings regressed or resolved following chemotherapy.
Conclusion: The thymus is commonly involved in Langerhans' cell histiocytosis, especially in multisystem disease. Radiologically, the thymus is enlarged and may be smooth or lobulated/nodular in contour, possibly containing cysts and calcifications.