Choroid plexus carcinoma

Choroid plexus neoplasms include papillomas and carcinomas, with carcinomas being very rare tumors. They are usually diagnosed in the pediatric age group accounting for 0.6% of pediatric intracranial tumors (1). These lesions are commonly found in the lateral ventricles and rarely in fourth and third ventricles (2). Clinical presentation is variable with symptoms that can be attributed to elevated intracranial pressure and hydrocephalus including increasing head circumference, diplopia with sixth nerve palsy, ataxia, papilledema, nausea and vomiting (3). Choroid plexus carcinomas are intraventricular tumors of primitive neuroectodermal origin. They are less common than papillomas with 80% of tumors arising from choroid epithelium being papillomas (19). Hydrocephalus is caused by induction of hypersecretion of cerebrospinal fluid or mechanical obstruction. Differentiating these tumors from papillomas on imaging is difficult in an index case. On MR imaging, the tumors are heterogenous in signal intensity on T1 and T2 weighted images due to components of necrosis, hemorrhage and calcification. The lesions show intense enhancement and flow voids are seen due to hypertrophied vessels. Irregular enhancement and edema reflect parenchymal invasion and distant metastases may be seen as leptomeningeal enhancement (4, 5). Differential diagnosis includes other intraventricular tumors including choroid plexus papillomas, ependymoma and atypical rhabdoid tumor (5). In the case presented, there was a solid mass in the right foramen of Luschka (fig.3) with similar imaging characteristics to the lesion in the left lateral ventricle indicating a metastasis in addition to diffuse leptomeningeal enhancement (fig.4).