Testicular cancer is the most common tumor in men aged 15 to 44 [18, 19], which is generally divided into germ cell tumors and non germ cell tumors. Germ cell tumors include several cell types, roughly divided into seminoma and non seminoma. Among them, choriocarcinoma is a non seminoma germ cell tumor, which is the most rare, accounting for 1% - 3% of all testicular tumors [20]. At present, the cause of testicular choriocarcinoma is not clear, which may be related to a variety of risk factors. Cryptorchidism may be one of the important factors leading to testicular choriocarcinoma. It is reported that the probability of cryptorchidism patients with choriocarcinoma is 20-40 times higher than that of normal testis [21] in this paper, the patient is left cryptorchidism, which may be one of the important factors leading to testicular choriocarcinoma.
Choriocarcinoma mainly metastasizes through blood. Because of its strong invasiveness to blood vessels and tissues, it leads to tissue bleeding and necrosis. Metastasis occurs early and widely. Therefore, when choriocarcinoma is diagnosed, a large number of cases have metastasized, so that most of the initial manifestations are metastasis related symptoms [22]. Because the most common metastatic sites are lung, liver and brain [23], patients usually show seizures, stroke like symptoms, blurred consciousness and-or hemoptysis. Gastrointestinal metastasis of choriocarcinoma is very rare. Gastrointestinal metastasis occurs in 5% of germ cell tumors. Gastrointestinal metastasis is considered to be the result of direct diffusion or hematogenous diffusion from adjacent retroperitoneal lymph nodes, and direct infiltration is more common than hematogenous diffusion. The small intestine, the most common duodenum, is the most common metastatic site (72%), followed by the esophagus, stomach and colon [6, 24]. The involvement of the small intestine is characterized by intestinal obstruction or gastrointestinal bleeding, usually abdominal pain, black stool or anemia. In this paper, the patient was treated with repeated black stool as the first symptom, but in the follow-up examination, it was found that there were tumor metastasis in the lung and liver in addition to small intestinal metastasis, but did not show clinical symptoms.
The determination of serum tumor markers HCG and AFP may be helpful in the diagnosis of choriocarcinoma because they are elevated in about 80% of cases. The serum concentration of HCG can also be used to monitor the response to treatment. According to the international cooperative organization for germ cell cancer, HCG higher than 50000miu/ml indicates poor prognosis. However, in this paper, the monitoring of HCG level after radical resection of testicular cancer is ignored, which leads to multiple metastasis and poor prognosis. In addition, as a transcription factor, GATA3 is another immune tumor marker sensitive to choriocarcinoma[25].
The imaging of testicular choriocarcinoma lacks characteristic changes that can be distinguished from other types of germ cell tumors. It is difficult to diagnose choriocarcinoma first. Most of the specimens obtained during surgical resection are confirmed by pathology. The typical histopathological feature of metastatic choriocarcinoma is the coexistence of cytotrophoblast and syncytiotrophoblast cells without mesenchymal cells, which is different from other germ cell tumors with only scattered syncytiotrophoblast cells.
The treatment of testicular choriocarcinoma depends on the stage of the disease. Radical orchiectomy and dissection of affected lymph nodes are the treatment of early diseases. The treatment of bleeding caused by gastrointestinal metastasis of choriocarcinoma is similar to that of other gastrointestinal bleeding, including endoscopic intervention, embolization or surgical resection. Abdelkader et al reported a case of bleeding from duodenal choriocarcinoma. The exudation point was ablated by an endoscopic adrenalin injection and argon plasma coagulation system to finally stop bleeding [12]. Bain et al. [7] Reported a case of bleeding treated by angiography and embolization. Iglesias et al. [26] Used surgical hemostasis after endoscopic injection of adrenalin and argon plasma coagulation system ablation failure. In this paper, because there was no bleeding focus under endoscopy and selective angiography, the patient finally stopped bleeding by surgical means.
Chemotherapy consolidation is usually required after bleeding stops. For metastatic choriocarcinoma, platinum therapy is recommended as the first-line chemotherapy, but unfortunately, choriocarcinoma is not so sensitive to chemotherapy. Most patients' tumors progress so rapidly that they do not respond to the standard chemotherapy regimen of three to four cycles of BEP (bleomycin, etoposide and cisplatin) [27]. In recurrent cases, salvage chemotherapy with vincristine and ifosfamide may help to reduce the tumor burden, but these patients may finally have to choose palliative treatment. Simple testicular choriocarcinoma usually has a poor prognosis, with a five-year survival rate of less than 80% [20]. In some reports, the long-term survival rate is even lower [28, 29], while mixed choriocarcinoma is slightly better. In this paper, the patient was treated with paclitaxel, ifosfamide and cisplatin.
Testicular choriocarcinoma is a rare tumor with strong invasiveness and rapid growth in young men. It mainly metastasizes to the lung, liver and brain. Reports of metastasis to the gastrointestinal tract are rare, which makes it easy to ignore the existence of the disease in the clinical diagnosis and treatment of gastrointestinal bleeding. Therefore, we recommend a more detailed inquiry into medical history and systematic examination. It is very important for us to correctly distinguish and diagnose the etiology of gastrointestinal bleeding. The lack of accurate physical examination and laboratory examination will lead to waste of patients' diagnosis and treatment time, the increase of mortality, the extension of hospital stay, and the increase of patients' medical expenses. Therefore, for any young male patient, the most basic reproductive system examination is very important. Among the patients in this article, the reproductive system examination was omitted during the patient's repeated hospitalization outside the hospital, and it was not carried out when he was admitted to our hospital. In addition, the detection of HCG was also omitted. Although the final surgical pathology guided us to diagnose testicular choriocarcinoma, during the process, the patient once had hemorrhagic shock, which may have been life-threatening, and we don't know how many patients died because their doctors missed this article.