Macro Pituitary Adenoma and Frontal Calcified Cavernous Malformation: A Coincidence or a True Partnership?

Collision tumors are rare neoplasms composed of two different types of histological tissues in the same organ. The most frequent association with cerebral cavernous malformations (CCMs) are meningiomas, gliomas, and gangliogliomas, while the most frequent sellar collision is between pituitary adenoma (PA) and craniopharyngiomas, and still very few cases have been reported. We present the case of a 43-year-old woman who started two months ago with a fall from her height followed by severe headache and bilateral hemianopsia. An isointense, enhancing sellar tumor, and a right frontal lesion compatible with CCM were observed on MRI. Surgery was performed through anterior interhemispheric and endoscopic transnasal approaches for the cavernoma and the sellar tumor, respectively, removing both lesions and sending them to pathology. The sellar tumor corresponded to a PA showing positive immunohistochemistry for prolactin and follicle-stimulating hormone (FSH). In the post-op period, the patient developed a seizure and diabetes insipidus, for which she received appropriate treatment. Our findings were conclusive with a collision tumor, since both lesions presented two different histological tissues. Different densities were observed in both lesions using imaging studies, which were later confirmed with histopathology and immunohistochemistry.