10-year follow-up of a patient with high-grade serous ovarian carcinoma and concomitant Henoch-Schönlein purpura nephritis, with metachronous liver and brain metastases: a case report

Background Brain metastasis from high-grade serous ovarian carcinoma (HGSOC) is rare, and serum Carbohydrate Antigen 125 (CA125) monitoring has limited surveillance value in this setting. Clinical evidence guiding the diagnosis and management of patients with such rare clinical presentations and comorbidities remains limited. Case presentation We report a patient with HGSOC (FIGO stage IIIB) who was followed for 10 years, from the initial diagnosis in 2016 to the latest follow-up in October 2026. She was clinically diagnosed with Henoch-Schönlein purpura nephritis (HSPN), complicated by synchronous HGSOC. She underwent cytoreductive surgery followed by docetaxel plus carboplatin (TC) chemotherapy. In 2018, HSPN recurred concurrently with surgical-site recurrence and hepatic metastasis. Following chemotherapy, HSPN remitted without specific immunosuppressive treatment, while the hepatic lesions achieved near-complete remission. In 2021, she developed a solitary left occipital brain metastasis, and her clinical symptoms improved after surgical resection, whole-brain radiotherapy and chemotherapy. Intracranial tumor recurrence was confirmed in 2022. Genetic testing in 2023 identified a pathogenic germline mutation in breast cancer susceptibility gene 1 ( BRCA1 ), with positive homologous recombination deficiency (HRD) status. She subsequently received pamiparib-based therapy, including combination treatment with bevacizumab. At the latest follow-up, she remained neurologically asymptomatic with an ECOG performance status of 1. Conclusions This case demonstrates a temporal association between HSPN activity and the clinical course of HGSOC, raising the possibility of a tumor-associated immune phenomenon. In addition, prolonged disease control was observed during treatment with pamiparib plus bevacizumab in this patient with HGSOC brain metastasis harboring a pathogenic germline BRCA1 mutation and HRD positivity.