Inflammatory pseudotumor (IP) is a benign process that most commonly occurs in the lung and orbit. Extension into the central nervous system is extremely rare, and primary intraventricular lesions of the lateral ventricles are even more infrequent with only 2 cases reported in pediatric patients to date. Here, the authors present an unusual case of IP occurring in a 16-year-old female presenting with a 2-week history of progressive headaches and vomiting, without focal neurological deficits or radiographic evidence of hydrocephalus. The patient underwent left parietal craniotomy and complete resection of the tumor, with no signs of recurrence at 3-month follow-up. Although the rarity of intraventricular IP in pediatric patients can make its initial identification difficult, IP should be considered as a potential diagnosis in this population wherein good outcomes may be achieved following surgical resection.

Metastases of lateral ventricle (LV) are attached to choroidal plexus. Primary source is cancer of kidney. Two thirds of patients are male. Oligodendrogliomas occur in young females. Signs of increased intracranial pressure are a constant feature. These tumors are found in anterior portion of the LV with severe enhancement and clumped calcifications. Treatment is surgical. Cavernomas have a preponderance of rapid growth with a bleeding revelation. Seizures are rare. Rebleeding is frequent and justifies a surgical treatment. Schwannomas are a rare entity in which the majority of patients are very young. MRI shows calcifications, cystic components and a strong enhancement. They are limited to sporadic cases, never associated with neurofibromatosis. Arachnoid cysts are located in the atrium and/or in the occipital horn. Patients are young (mean age < 40 years). MRI demonstrates an intracystic lesion with signal intensity similar to the CSF. Best treatment is an endoscopic fenestration. Epidermoid cysts occur in third decade. These pearly tumors appear isointense or a little hyperintense on T1-weighted imaging, very characteristic. They are enhanced after gadolinium injection and appear strongly hyperintense on T2-weighted imaging. An incomplete removal with a thorough long-term follow-up is necessary. Cavernomas of LV are hyperintense on T1- and T2-weighted imaging. They have a bleeding risk of 25 to 45%. Therefore, they must be operated.

Inflammatory pseudotumors (IP) are non-neoplastic lesions characterized by collagenous stroma and polyclonal mononuclear infiltrates. It is best characterized in the lung, but can occur in the CNS, mimicking a neoplastic process. We discuss the available literature and our cases in order to elucidate best medical practices when confronted with such a lesion. We report on two cases of intraventricular inflammatory pseudotumor in patients who presented with symptoms of CSF obstruction. Both patients were treated surgically with significant clinical improvement. Histopathologically, both specimens revealed a plasma cell granuloma variant of IP. A Medline search for English articles identified 46 cases of CNS IP, only eight of which were located within the ventricle. As with our case, most patients presented due to CSF obstruction or mass effect. Radiographically, the lesions have a variable appearance although most enhanced with gadolinium. Complete resection was achieved in 67% with a 12% rate of recurrence. With incomplete resection or biopsy alone, progression is seen despite steroid or radiation administration. Malignant transformation was only reported once. CNS IP is a rare pathological entity that cannot be diagnosed through clinical presentation or radiographic characteristics, but rather through a careful neuropathological inspection. The available literature suggests that complete resection with close follow-up is necessary.

Inflammatory pseudotumor is an uncommon lesion with unknown etiology characterized by sclerosing inflammation which clinically and radiographically mimics a neoplastic lesion. A 47-year-old man presented with sudden headache and dysarthria. Brain CT scan revealed a 2.6x2.2 cm sized, round, and hyperdense mass in the anterolateral wall of the left lateral ventricular trigone. On MR imaging studies, the mass showed low signal intensity in the wall of the trigone on T2-weighted image, central mixed (iso- and high-) signal intensity with peripheral low-signal intensity on T1-weighted image. Subtle staining of left choroid plexus with irregular shaped distal branch of anterior choroidal artery was found on the cerebral angiography. These findings suggested a small tumorous lesion originated from the left choroid plexus. During the hospital days, the mass manifested as repeated hemorrhages. The mass was successfully removed via left occipital transcortical approach. The histopathological report of the specimen was hemorrhage and fibrosis, with dense lymphoplasma cell infiltration, suggestive of an inflammatory pseudotumor.