Unusual presentation of mastoid eosinophilic granuloma in a young patient

Eosinophilic granuloma is a well-recognized form of Langerhans cell histiocytosis, most commonly involving the skull bones, usually with an excellent prognosis. Recurrent and difficult to recognize osteolytic lesions of the skull are encountered only rarely. A patient with recurrent eosinophilic granuloma of the skull is reported. In spite of appropriate multimodality treatment, there were several recurrences, most recently with involvement of the mastoid process. Imaging studies revealed extensive involvement of surrounding structures with expansion of the tumor into the middle cranial fossa and slight pressure on the antero-medial portion of the temporal lobe of the brain. Despite extensive involvement, the patient had no complaints. Because of the rarity of such silent and unpredictable lesions, a systematic approach with regular CT and MRI follow-up is suggested.