Choroid plexus tumours on MRI: similarities and distinctions in different grades

Abstract

Background: The therapeutic planning varies for different grades of choroid plexus tumours (CPTs). The aim of this study was to define the similarities and distinctions among MRIs for different grades of CPTs, providing more guidance for clinical decisions.

Methods: We reviewed the MRI findings in 35 patients with CPT verified by surgical pathology, including 18 choroid plexus papillomas (CPPs, grade I), 11 atypical choroid plexus papillomas (aCPPs, grade II), and 6 choroid plexus carcinomas (CPCs, grade III). Nonparametric testing based on ranks was performed to evaluate the association of pathological grade with MRI findings.

Results: Among the 35 CPTs, 29 were located in the ventricular system. The tumours were generally slightly hypo- or isointense on T1WI, slightly hyper- or isointense on T2WI, and moderately or strongly enhanced in post-contrast imaging. Twenty cases were accompanied by hydrocephalus. The median tumour longest diameters of CPPs, aCPPs, and CPCs were 28.6, 44.6, and 60.6 mm, respectively. Four cases were purely cystic, 6 were papillary, 10 were lobulated, and 2 were irregular. Three cases had necrosis. The median oedema diameters of CPPs, aCPPs, and CPCs were 0, 0, and 24.1 mm, respectively. The grades of CPTs were statistically associated with tumour longest diameter (r_s = 0.68, P < 0.001), internal morphology (χ² = 10.32, P = 0.016), necrosis (Z = 2.27, P = 0.023), and oedema diameter (r_s = 0.72, P < 0.001).

Conclusion: CPTs typically appeared as intraventricular papillary or lobulated lesions, often accompanied by hydrocephalus. Larger tumour, irregular or fuzzy internal morphology, presentation of necrosis and wide-ranging peritumoural oedema might increase the likelihood of malignancy.

Keywords: Atypical choroid plexus papilloma; Choroid plexus carcinoma; Choroid plexus papilloma; Choroid plexus tumour; Magnetic resonance imaging; Pathological grade.

Fig. 1

The CPTs with typical papillary/lobulated/irregular internal morphology. The CPPs with papillary internal morphology (a. T2WI, b. T1WI, c. post-contrast). In the pathology image of case b, the tumour cells are arranged in a papillary structure with vascular at the centre (d). The CPC (e. FLAIR) and aCPPs (f, g. post-contrast) with lobulated internal morphology. In the pathology image of case e, the tumour cells are arranged closely, with focal necrosis and haemorrhage (h). The CPCs with irregular internal morphology (i. FLAIR, j. T2WI, k. post-contrast). In the pathology image of case i, the papillary structure is irregular and complex, and the distribution of tumour cells is dense (l)

Fig. 2

CPP (grade I). A 3-month-old boy with a purely cystic lesion in the right foramen of Monro. Bilateral lateral ventricles have severe obstructive hydrocephalus, and T2WI shows that the signal intensity in the cyst is identical to that of the CSF (a). Axial (b) and coronal (c) post-contrast images show that only thickened enhanced choroid plexus is attached to the cyst wall

Fig. 3

CPP (grade I). A 4-year-old boy with a papillary lesion in the left lateral ventricular trigone. The tumours are slightly hyperintense on T2WI (a), isointense on T1WI (b), and strongly enhanced in post-contrast imaging (c) and are connected to the choroid plexus by a vascular pedicle

Fig. 4

aCPP (grade II). A 2-year-old girl with a lobulated lesion in the fourth ventricle. The tumour is slightly hyperintense on T2WI (a) and FLAIR sequence (b) and isointense on T1WI (c), with a more heterogeneous internal structure. Sagittal post-contrast imaging shows that the tumour is strongly enhanced (d), and serious hydrocephalus is visible in the supratentorial ventricles

Fig. 5

CPC (grade III). An 8-month-old girl with a lobulated lesion in the right lateral ventricular trigone. The solid part of the tumour is isointense on T1WI with multiple intratumoural necrosis and cysts. The surrounding brain parenchyma shows widely arranged oedema (a). Sagittal post-contrast imaging shows that the tumour is strongly enhanced (b). DWI sequence (c) reveals a hyperintense area, corresponding with a slightly hypointense area on the ADC map (d)

Fig. 6

CPC (grade III). A 59-year-old male with an irregular massive lesion in the right temporal lobe, with multiple intracranial solid-cystic metastases. The solid part of the tumour is heterogeneous hyperintense on T2WI (a) and moderately enhanced in post-contrast imaging (b). Four years after the gross resection of the temporal lobe lesion, the solid-cystic metastases are increased and enlarged (c). Disseminations are shown in the spinal canal and are strongly enhanced in the post-contrast imaging (d)

Fig. 7

Distribution of tumour longest diameter and oedema diameter in relation to pathological grades