A mixed choroid plexus papilloma and ependymoma

Abstract

We report a novel case of a mixed choroid plexus papilloma (CPP) and ependymoma with cartilaginous differentiation. This kind of mixed tumor has not been previously reported in the English literature. The patient was a 5-year-old girl, who presented with a 1-week history of fever and numbness of the right lower limb. Magnetic resonance imaging of the brain with gadolinium revealed a heterogeneously enhancing mass in the occipital horn of the left lateral ventricle. Histologically, the tumor showed an intermixed CPP area and a low-grade papillary ependymoma-like area, which was studded with cartilage islands and psammoma bodies. In many foci, direct transition of CPP and ependymoma was observed, but there were no high-grade features. We report this novel case, describe the unique microscopic and immunohistochemical features, and speculate on the pathogenesis.

Posterior fossa choroid plexus papilloma with focal ependymal differentiation in an adult patient: A case report and literature review

“…In 1981, Rubinstein and Brucher initially reported nine cases of CPPs exhibiting focal GFAP positivity in the tumor cells [4] . Since then, several reports have documented mixed tumors composed of CPP and other tissues such as ependymoma and hemangioblastoma [2] , [3] . Focal GFAP positive cells are often seen in CPP without ependymal differentiation [5] .…”

“…Two hypotheses have been proposed to explain the pathogenesis of CPP containing other tissues. The first is that when pia and blood vessels invaginate into the ventricle during development of the choroid plexus, other mesenchymal components and adjacent neuroglial tissue can be included, and they may differentiate into certain types of tissues [2] . The other is that the multipotent primitive cells of the circumventricular organs, which are precursor cells of SECO, might differentiate into diverse cell lineages when they form a tumor [2] .…”

“…The tumor was grossly totally resected; however, the patient developed a coma because of substantial intraoperative bleeding. The other case involved a 5-year-old girl who presented with a 1-week history of fever and numbness of the right lower limb [2] . Brain MRI with gadolinium revealed a heterogeneously enhancing mass in the occipital horn of the left lateral ventricle with a small cystic lesion adjacent to the mass.…”

“…The optimal treatment of CPP with ependymal differentiation is also yet to be determined because of its rarity. Former case reports indicated no recurrence or metastasis after surgical removal of CPPs containing other tissues [2] , [3] , and McGirr et al reported that the presence of ependymal differentiation did not correlate with either the difficulty of resection or tendency for recurrence [20] . Although the prognosis of this tumor has not been thoroughly discussed, complete resection should be performed as for ordinary CPPs.…”

“…Choroid plexus papillomas (CPPs) are rare, indolent neoplasms classified as World Health Organization grade I tumors [1] . To date, CPPs containing other tissues have occasionally been documented in the literature [2] , [3] . However, these reports have mainly focused on pathological features; few have provided clinical and radiological information.…”