Sonographic diagnosis and monitoring of localized langerhans cell histiocytosis of the skull.

PURPOSE

Langerhans cell histiocytosis (LCH) is an infrequent disorder of unknown origin associated with histiocytic proliferation. The bones' involvement (including cranial bones) is the most frequent manifestation of pediatric LCH. Imaging of skull LCH is based predominantly on conventional radiography, CT, scintigraphy, and sometimes MRI. The aim of the study was to investigate the role of sonography (US) in the diagnosis and monitoring of bone lesions in children with localized LCH of the skull.

METHODS

Twenty-seven children (15 boys/12 girls, mean age 6.1 years) were diagnosed between 1991 and 2005 in the Department of Pediatrics at the Medical University of Gdansk, Poland. Fourteen children (52%) had localized LCH of the skull.

RESULTS

All lesions of the skull visible on CT were visualized on US examination. Overall, 30 focal lesions were revealed by US. The largest bone lesions were accompanied by changes within the adjacent soft tissues. CT revealed 26 lesions, the location and size of which corresponded to the lesions seen on US, but soft-tissue changes adjacent to the bony lesions were difficult to visualize.

CONCLUSIONS

The US appearance of focal LCH lesions in cranial bones in children is not pathognomonic, but is characteristic enough to suggest an initial diagnosis and to monitor the evolution of lesions during treatment. US should be considered an additional diagnostic tool for LCH of the skull. Although US of localized LCH cannot replace CT, it could reduce the number of follow-up CT examinations.