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.
Aim of study: 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: We analyzed US and CT scans of 30 children (11 retrospectively and 19 prospectively) suffering from LCH. All children were diagnosed and treated in a single oncologic center, between 1991 and 2012. The group consisted of 18 boys (age range, 1–17 years) and 12 girls (age range, 1month–16 years). The mean age of the study group was 6.1 years.
Results: All lesions of the skull visible on CT were visualized on US examination. Overall, 33 focal lesions were revealed by US. The largest bone lesions were accompanied by changes within the adjacent soft tissues. CT revealed 29 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.
In 19 patients with localized LCH, US was used for follow-up and monitoring of the lesions. US clearly showed the reconstruction of the pericranium and the disappearance of soft-tissue changes
Conclusions: Sonograms of focal lesions in children with LCH of cranial bones are not pathognomic, but are characteristic enough to suggest the 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.
