Intraosseous or intradiploic arachnoid cysts of the cranial vault are extremely rare lesions, representing herniations of the arachnoid membrane through a dural and inner table defect. A 35-year-old woman presented with progressive headaches and a slowly enlarging, non-tender left parietal swelling without any history of trauma. Imaging revealed a left parietal intraosseous cystic lesion with CSF-like signal intensity, thinning of the outer table, and communication with the subarachnoid space. Surgical exploration confirmed multiple small openings in the outer table with CSF outflow and an underlying dural defect. The cyst was excised, the dura repaired watertight, and the cranial vault reconstructed. The postoperative course was uneventful, and follow-up imaging at three months showed no recurrence. This case highlights an exceptional presentation of an intraosseous arachnoid cyst with dural communication. Recognition of this rare entity is essential for accurate diagnosis and proper surgical management.

Collision tumors are defined as ≥2 histologically distinct tumors existing in the same anatomic location. Generally, collision tumors are rare, and if they occur in the sellar region, common combinations are pituitary adenoma with Rathke cleft cyst (most common), however the association of pituitary tumors with hypopthalamic tumors remains extremely rare. We report in an observation the case of a pituitary adenoma diagnosed after 5 years of a surgical cure of a craniopharyngioma. Although described in a few observations through the medical literature, it is an extremely rare condition illustrating the possibility of having 2 different neoplasias, within the hypothalamic-pituitary region. The chronology of the appearance of the 2 histological entities (or more than 2) is decisive first on a semantic level, this then allowing to better classify into one of collision, composite, or in coexistence forms. The management of these tumors of the pituitary region involves effective surgery but also a good endocrine evaluation in order to treat pituitary hormone deficiencies, sometimes with a vital prognosis (replacement with corticosteroids and thyroxin), or functional (GH, sexual steroids and gonadotrophins). The prognosis of these tumors that occurred in a collision mode remains less good compared to solitary tumors of the hypothalamic and hypopjhyseal region.

Hemangioblastomas are sporadic tumors found in the cerebellum or spinal cord. Supratentorial hemangioblastoma are exceedingly rare tumors. We present a case of cerebral hemangioblastoma not associated with von Hippel-Lindau disease. A 35-year-old woman was admitted to a hospital with one mouth history of headache associated with partial seizures. Magnetic resonance imaging revealed a giant cystic mass occupying much of the right frontal hemisphere, with a hyperdense mural nodule. During surgery, the cyst was evacuated, and the mural nodule was completely excised. The postoperative course was uneventful. The histopathologic findings were considered consistent with hemangioblastoma. The finding of a cyst with a mural tumor nodule in the cerebral hemispheres suggests primarly a benign astrocytoma, but other tumors can present in a similar form. The treatment of choice for supratentorial hemangioblastoma is surgical resection. We report a case of supratentorial hemangioblastoma, review the literature, and discuss the radiopathological correlation and diagnostic difficulties associated with such lesions.