Abstract: Background:Choroid plexus carcinoma (CPC) is very rare in children, and there are few reports in China about this special cohort. Objective:To investigate the clinical features, treatment and survival outcome in pediatric CPC patients. Design:Case series report. Methods:Children with CPC confirmed by pathology after tumor resection, who were admitted to pediatric department of Beijing Shijitan Hospital from January 2017 to October 2022, were retrospectively analyzed. The last followup was December 31, 2022. The sex, age at diagnosis, clinical features, treatment and followup were collected. KaplanMeier method was adopted for survival analysis. Main outcome measures:Overall survival (OS) and progressionfree survival (PFS). Results:Among the 12 included patients, four were males and eight were females. The median age at diagnosis was 29.7 (range, 5.8119.6) months, with 8 cases less than 3 years old at the time of diagnosis, tumor diameter ≥5cm in 8 cases, and <5cm in 4 cases. Nine cases were supratentorial, and 3 were infratentorial. The tumor was located in ventricular system in 6 cases, and external involvement of brain parenchyma in 6 cases. Two cases experienced metastases (M+) and 10 patients without metastasis (M0) at the time of diagnosis. All the patients received tumor resection with 8 cases under gross total resection (GTR) and 4 near total resection (NTR). Five (42%) cases received chemotherapy only and 7 patients (58%) were treated with both radiotherapy and chemotherapy after surgery. At the time of last followup, 8 cases experienced tumor recurrence or progression, and 4 cases died. The mean OS were (56.7±8.8) months. The 1, 3, 5year OS were (83.3%±10.8)%、(66.7%±13.6)%, and (66.7%±13.6)%, respectively. The mean PFS time were（24.3±7.2）months. The 1, 3year PFS were (41.7%±14.2)% and (33.3%±13.6)%, respectively. The KaplanMeier univariate analysis showed the 3year OS was poorer in children with infratentorial tumors than those with supratentorial tumors (χ2=8.562, P=0.003). And the 3year OS was also lower in patients who received chemotherapy only than those who received radiotherapy in combination with chemotherapy (χ2=8.488, P =0.004). The difference in 3year PFS was not satistically significant in gender,age at diagnosis(< 3 years old and 318 years old) , tumor diameter (<5 cm and ≥5 cm), GTR and NTR, metastasis or not, chemotherapy only or in combination with radiotherapy (P>0.05). Conclusions:CPC is very rare with poor prognosis in children. Children with infratentorial tumors and who received chemotherapy only tend to have poorer OS.

Key words: Choroid plexus carcinoma, Children, Treatment