CT Findings of Orbital Langerhans Cell Histiocytosis

ABSTRACT

PURPOSE: To evaluate the CT findings in patients with Langerhans cell histiocytosis (LCH) involving the orbit. MATERIALS AND METHODS: Orbital CT scans of six children with pathologically proven LCH were retrospectively analyzed. Follow-up CT (n = 5) and MR (n = 1) imaging findings were also revi ewed. RESULTS: Initial CT scans revealed varying degree of bone destruction with soft-tissue masses, and on nonenhanced images the mean attenuation value was 44 Hounsfield units(HU). All masses showed mild to moderate enhancement with a mean attenuation value of 74 HU. The bony margins abutting onto soft tissue masses were irregular but clearly demarcated. No evidence of calcification or periosteal reaction was noted. Suprasellar mass and rib involvement was noted in one patient and hepatos-plenomegaly in two. Follow-up CT and MR images showed that the soft tissue masses were almost completely resolve d, with bone remodeling and reossification. CONCLUSION: A soft tissue mass with irregular but clearly demarcated bone destruction is thought to be a characteristic finding of LCH involving the orbit. Follow-up images after treatment showed bone remodeling and reossification.