Langerhans cell histiocytosis of the parieto-occipital bones in infancy; a case report with CT and MR features

A 14-month-old boy had a right postauricular soft mass that rapidly enlarged in the 3 months before initial presentation. He had cervical lymph node swelling and seborrheic dermatitis in the postauricular region. Laboratory findings were normal except for mild anemia. Plain skull films showed a 'punched-out' lesion in the right parieto-occipital bones. CT scan of the brain demonstrated a 7 x 7 x 3.5 cm mass centered in the left parietal bone which was enhanced after administration of a contrast medium. On MRI, the mass was isointense to the cerebral cortex on T1-weighted images and hypointense with peripheral hyperintensity on T2-weighted images. A small mass showing the same intensity as the postauricular mass on MRI was also present in the ethmoid sinus. Histologically, the postauricular mass was diagnosed as a lesion caused by Langerhans cell hisiocytosis.