In this report, we introduced the development and treatment of peritoneal metastasis of germinoma. VP shunt was first conducted due to the urgent condition of obstructive hydrocephalus. When the patient’s condition fulfilled the requirements, standard chemoradiotherapy was processed and the tumor in brain diminished significantly. However, about 4 months after the chemoradiotherapy, germinoma was verified to metastasize to abdomen. He then received chemotherapy for over 6 months and abdominal germinoma was cured with no relapse detected 4 months since then.
As a rare tumor in CNS, germinoma showed a favorable prognosis with the 5-year survival rate higher than 85%. This is attributed to the high sensitivity of the tumor to chemotherapy and radiotherapy[3]. In clinical trials from 1983–1993 conducted by German Cooperative, patients received mere craniospinal irradiation (CSI) with 36Gy, and 50Gy as a boost on primary sites). As a result, relapse was found in only one patient among 60 and the 5-year survival rate was over 93%[4]. In comparison with CSI, Rogers et al. suggested whole-brain radiation led to similarly low incidence of spinal relapse[5]. Therefore, radiation alone could be effective, instead of the elevated possibility of long-term sequelae since it needs high dose and vast fields. As another approach, chemotherapy-only was investigated in clinical trials using regimens with carboplatin, bleomycin, etoposide and cyclophosphamide. However, this therapy is less effective than radiotherapy according to 5-year survival rate and recurrence rate[6, 7]. In this context, concurrent chemoradiotherapy is believed to maximize the therapeutic effect of radiation and minimize the side effect of large dose and volume. Indeed, clinical trials in France and Japan demonstrated notably higher survival rate which could be over 98%[8, 9]. Surgical removal is not recommended because of the negligible benefits and additional risks[10], however, surgery for biopsy is acceptable when necessary[8].
This case inspired us about the opportunity of performing shunt and chemoradiotherapy. The patient complaint of severe headache and CT demonstrated remarkable obstructive hydrocephalus, so that VP shunt was initially operated in case of emergency. Following operation, concurrent chemoradiotherapy was performed as soon as his situation permitted. Although the treatment had never resulted in peritoneal metastasis in our hospital, there are cases presenting peritoneal metastasis via shunt. For example, Murray et al. introduced a case in which a 13-year-old female presented with hydrocephalus. VP shunt was placed, followed by craniospinal radiotherapy and the tumor was eliminated completely[11]. Although shunts are effective tools draining excessive craniospinal fluid (CSF) to abdomen, they create a latent way for peritoneal metastasis of intracranial tumors. Some people advocated the shunts with filters to lower the probability, nonetheless, the chance of shunt obstruction naturally increases[12]. As another means of CSF bypassing, endoscopic third ventriculostomy which creates a defect in floor of third ventricle communicates with interpeduncular cistern, precluding the risk of extra-neural metastasis of germinoma. However, when tumor developed on suprasellar region, the ventriculostomy will be dangerous. Furthermore, severe or even fatal complications such as bleeding and neural structure injury should be taken into considerations[13]. Although this patient exhibited notably sensitivity to chemotherapy and CSI, this could not exempt the chance of metastasis during the treatment. Therefore, timing of radiotherapy after VP shunt should be noticed because it may cause peritoneal metastasis if too late, or may be hazardous to wound healing and patients’ general conditions if too early. As an alternative, performing radiation simultaneously with external drainage might be taken as a proper strategy, yet requiring clinical trials.
In treating abdominal germinoma in this patient, it was interesting that mere chemotherapy was sufficient. Remedy of etoposide plus platinum has long been verified effective in treating CNS germinoma, as evidenced in this case either. However, its therapeutic effects are generally inferior to radiotherapy and the reason might be the presence of blood-brain barrier (BBB)[14]. For this patient, chemotherapy illustrated excellent therapeutic effect on abdominal germinoma since agents would reach effective plasma concentration much easier in abdomen which lack BBB. Meanwhile, exemption of radiotherapy could also refrain patients from the risk of radiation complications such as enteritis[15].Therefore, chemotherapy with etoposide and platinum comes to the priority and additional choices such as dasatinib, temozolomide and GEMOX (gemcitabine and oxaliplatin) can also be applied[16–18]. To date, remedy of agents for treating metastatic germinoma lack a definite standard, and is probably dependent on factors such as age, serum markers, metastatic sites and sensitivity to platinum. For example, temozolomide showed negligible effect on patients of cisplatin-refractory metastatic germ cell tumor with AFP > 15 µg/L and elevation of β-HCG > 2.2 mIU/L, but it may not necessarily imply the effects on patients within other restrictions[17]. In short, intensive study on chemotherapy of metastatic germinoma is required for standardization of agent choice in diverse situations.
As concluded in this report, we introduced a patient with germinoma suffered from abdominal metastasis following standard chemoradiotherapy, inspiring us to reflect on the treatment of CNS germinoma with urgent hydrocephalus. This male received VP shunt when he was admitted to hospital due to the emergent hydrocephalus, followed by concurrent chemoradiotherapy and chemotherapy. However, giant germinoma metastasized to abdomen via shunt was confirmed 4 months later and then cured by chemotherapy for 6 cycles. This case inspired us to reflect on the treatment of CNS germinoma with hydrocephalus and suitable chemotherapy on metastatic germinoma.