A 5-month-old boy presented with a solitary occipital growth. The lesion was of hard consistency, immobile, painless, measuring 2×3 cm with no relevant lymph node involvement. The overlying skin was intact. There was no relevant family history.

Ultrasound scan revealed a bony lytic lesion. Initial CT and MRIs were suspicious of Langerhans cell histiocytosis. The lesion was indenting into cerebellar hemispheres, contacting but not indenting the venous sinuses (figure 1 …