Solitary eosinophilic granuloma of the calvaria

Histiocytosis X is a condition characterized by an abnormal proliferation of histiocytes with a variable granulomatous and inflammatory component; bone involvement is almost always present. The aim of this study was to define the management of solitary eosinophilic granuloma (EG) of the calvaria in adult patients, in relation to the size and site of the lesion.

Fourteen patients, ranging in age from 7 to 45 years, with solitary eosinophilic granuloma of the calvaria were surgically treated by craniectomy or curettage and cranioplasty. We subgrouped the lesions into two types: A) lesions localized inside the diploë and/or compressing the cerebral parenchyma below but without dural infiltration; B) lesions with mainly intracranial growth, compressing the cerebral parenchyma and infiltrating the dura. The infiltrated dura mater in type B lesions was replaced with a dural patch. Cranioplasty was performed in lesions with a diameter of 4 cm or more and/or located in aesthetically exposed areas of the skull.

None of the patients died during the study and no local or systemic recurrences were observed during follow-up (min. 3 yrs, max. 8 yrs).

Surgical treatment of patients with isolated EG of the calvaria not only is simple and quick but also allows histological diagnosis of the osteolytic lesion. These patients do not require further adjuvant treatment. Cranioplasty should be performed when the lesion has a diameter of 4 cm or more, when it is located in aesthetically exposed areas of the skull such as the frontal or temporal bones, or when it produces alterations of the normal skull morphology.