A Case of Choriocarcinoma Undergoing Laparoscopic Surgery Due to Suspected Peritoneal Pregnancy

Abstract

Extrauterine choriocarcinoma is uncommon and may be mistaken for a ruptured ectopic pregnancy. Rapid diagnosis is essential, as massive intraperitoneal bleeding can be fatal. Once histologically diagnosed, choriocarcinoma is highly chemosensitive. This case describes a 38-year-old woman who presented with sudden lower abdominal pain. Six weeks after her last menstrual period, serum human chorionic gonadotropin (hCG) was 28,834 mIU/mL. No intra-uterine gestational sac was found, and intraperitoneal bleeding was observed, suggesting an ectopic pregnancy. An emergency laparoscopic surgery revealed a blood clot and active bleeding on the peritoneal surface near the ileocecal region, which was resected. Histology revealed sheets of syncytiotrophoblasts and intermediate trophoblast cells without villi, and immunohistochemistry was diffusely positive for Ki-67 and hCG, confirming primary peritoneal choriocarcinoma. Staging imaging revealed no other lesions. The patient received four cycles of MEA chemotherapy (methotrexate, etoposide, actinomycin D) at three-week intervals, resulting in sustained hCG normalization and no evidence of recurrence at follow-up. Primary peritoneal choriocarcinoma should be considered in the differential diagnosis of intraperitoneal bleeding during early pregnancy. Even when ectopic pregnancy is suspected, the excised tissue must be submitted for histopathological examination so that chemotherapy can be initiated promptly in case of choriocarcinoma.

Keywords: extrauterine choriocarcinoma; gestational trophoblastic neoplasia; laparoscopy; peritoneal pregnancy; pituitary hcg.

Figure 1. Intra-abdominal findings at laparoscopic surgery

(a) Significant bloody ascites. (b) No abnormal findings were found in the uterus or bilateral adnexa. (c) A 20 mm blood clot was found near the ileocecal area. (d) Active bleeding was observed from outside the ascending colon near the ileocecal area.

Figure 2. Histopathological examination of the resected tissue (H&E staining)

(a) 200×magnification; (b) 400×magnification; (a–b) Histology of the excised tissue showing the proliferation of syncytiotrophoblast cells and intermediate trophoblast cells

Figure 3. Immunohistochemical staining for hCG and Ki-67

(a-b) 200×magnification; (a-b) Histology of the excised tissue showing positivity for (a) HCG and (b) Ki67 in syncytiotrophoblast cells hCG: human chorionic gonadotropin

Figure 4. PET-CT and contrast CT of the lung

(a) A positron emission tomography (PET)-CT scan revealed a nodule with a high uptake in the right lung; (b) a contrast CT scan revealed no obvious nodule in the right lung

Figure 5. Treatment progress and serum hCG levels

Serum hCG levels during MEA therapy and subsequent EP therapy. Low-level hCG elevation after the third MEA cycle suggested a pituitary origin, which resolved following EP therapy. hCG: human chorionic gonadotropin; MEA: methotrexate, etoposide, actinomycin D; EP: luteinizing and estrogen hormones