2. Laboratory of Experimental Neuropathology. National Institute of Neurology and Neurosurgery, Mexico City.
3. Department of pathology. General Hospital of Mexico City.
Pituitary apoplexy is characterized by a sudden increase in pituitary gland volume secondary to ischemia and/or necrosis, usually occurring in the context of pituitary adenoma. Little is known about craniopharyngioma apoplexy. However, some cases have been reported, and it is usually an underused but necessary term in the presence of extensive necrosis and hemorrhage within Craniopharyngiomas. Here, we report two cases of craniopharyngioma apoplexy in a man aged 26 and a woman aged 30 years old, who presented this sellar tumor at an early age, both presenting recurrence and had previously undergone radiotherapy. In the previous recurrence, we observed histological findings related to extensive necrosis, fibrin thrombi, vascular damage and proliferation, inflammation, hemorrhage, fibrin foci, and epithelial reactive changes. Also, we observed pseudostratification, atypia and external epithelium pleomorphism, proliferation of the stellate reticulum with mitotic features as well. Strikingly, by immunohistochemistry, we described the overexpression of β-catenin only in loose cells found the middle of the extensive necrosis areas, displaying a high Ki67 index, found in its punctate form. Both cases showed the same histological pattern. Such findings hadn’t been described in Craniopharyngiomas; we suggest that these are related to apoplexy, post radiation changes or premalignant transformation, reason why this could be termed carcinoma in situ or high-grade intraepithelial lesion. The 2016 WHO classification for CNS tumors update does not consider new features related to malignant transformation occurring in Craniopharyngiomas.
Keywords: Craniopharyngioma, apoplex, necrosis, malignant transformation, ki67