ENDODERMAL CYSTS OF THE POSTERIOR-FOSSA - REPORT OF 3 CASES AND REVIEW OF THE LITERATURE

The pathogenesis of endodermal cysts of the posterior fossa is still i ncompletely understood. The authors reviewed three new cases and those reported in the literature to clarify the clinical, pathological, rad iological, and surgical characteristics of these lesions. A total of 4 9 cases were reviewed. Details on demographic profiles, clinical chara cteristics, histopathological and radiological features, and surgical methods were collected. These cysts have a predominance in male patien ts (61%) and can occur at any age (birth-77 years). in patients with p osterior fossa endodermal cysts there is a bimodal age distribution an d headache is the most frequent complaint. On immunohistopathological examination, endodermal cysts were reactive for epithelial membrane an tigen and for keratin immunostains whenever the latter were tested. Th e cysts were reactive fur carcinoembryonic antigen in nine of 11 cases . Endodermal cysts were located anterior to the brainstem in 51% of ca ses and in the fourth ventricle in 21% oi cases. They frequently appea red hypodense on computerized tomography scans. and in five cases, the lesion was missed. The cyst's appearance on magnetic resonance imagin g is variable. Resection was complete in 19 cases and partial in 11; m arsupialization was achieved in two cases. Three recurrences have been reported. Total excision with preservation of neurological function s hould be the goal. Cranial base approaches are helpful for surgical ac cess in selected examples of these lesions.