Calcifying Pseudoneoplasm of the Cerebellopontine Angle: Case Report

BACKGROUND AND IMPORTANCE: Calcifying pseudoneoplasms are rare tumors of the neuraxis. To our knowledge, this is only the second reported case in the literature of calcifying pseudoneoplasm of the cerebellopontine angle. The etiology and natural history of these neoplasms are not well understood. This case report provides a thorough review of the histology and potential origins of calcifying pseudoneoplasm. CLINICAL PRESENTATION: A 34-year-old previously healthy man presented with a 6-month history of progressive worsening headaches, fatigue, tinnitus, dizziness, and blurry vision. Neurological examination was notable for tongue deviation, tongue atrophy, and left uvula deviation. Computed tomography (CT) scanning showed a 3.3 x 3.5 cm densely calcified posterior fossa mass appearing to arise from the occipital bone. Magnetic resonance imaging (MRI) revealed a 4.3 x 2.9 x 2.9 cm left posterior fossa enhancing mass with the margin tip from the left occipital condyle. A transcondylar approach was used to resect the lesion. The mass was found to have eroded through the bone into the foramen magnum. Histopathological examination confirmed the diagnosis of calcifying pseudoneoplasm of the cerebellopontine angle. CONCLUSION: Calcifying pseudoneoplasms should be considered in the differential diagnosis of calcified cerebellopontine angle tumors. Histopathologic diagnosis is extremely important in the characterization of these lesions in order to direct the course of appropriate management. An inaccurate diagnosis of a malignant tumor can result in potentially harmful and unnecessary therapies, as prognosis for these lesions is generally favorable.