An   Unexpected Cause of Lower Gastrointestinal Bleeding: Primary Colorectal Choriocarcinoma in a Young Female.

Dr. Viswanath Reddy Donapati^1*, Dr. P. Rajasekhar Reddy¹, Dr. Vamshi A¹ , Dr. Milap Shah², Dr. Pavan Kumar Addala³, Dr. Bhanu Prakash B⁴

1-        Department of Medical Gastroenterology, Yashoda Hospital, Secunderabad, Hyderabad.

2-        Department of Pathology, Yashoda Hospital, Secunderabad, Hyderabad.

3-        Department of Surgical Gastroenterology, Yashoda Hospital, Secunderabad, Hyderabad.

4-        Department of Medical Oncology, Yashoda Hospital, Secunderabad, Hyderabad.

*Correspondence to: Dr. Viswanath Reddy Donapati,  Department of Medical Gastroenterology, Yashoda Hospital, Secunderabad, Hyderabad.

Copyright

© 2025 Dr. Viswanath Reddy Donapati, This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: 29 Sep 2025

Published: 08 Oct 2025

DOI: https://doi.org/10.5281/zenodo.17337613

Abstract

Lower Gastrointestinal Bleeding due to malignancy of Non-intestinal origin primary colonic causes is extremely rare condition. We hereby describe one such case of a 30-year-old female who presented with lower gastrointestinal bleeding and was ultimately diagnosed with primary choriocarcinoma of the distal sigmoid colon. Choriocarcinoma is a highly malignant germ cell tumor typically originating from gonadal or gestational tissues. Extra-gonadal, non-gestational choriocarcinomas of the gastrointestinal tract are exceedingly rare and often present with non-specific symptoms, leading to diagnostic delays. This case highlights the importance of considering rare malignancies in the differential diagnosis of rectal bleeding, particularly in young females.

Introduction

Lower Gastrointestinal tract bleeding is any bleed from the intestines below the level of attachment of the Ligament of Trietz. It could be of variable severity and a myriad of causes have been described. We recently encountered a case of Lower GI bleeding due to an unusual tumour of Sigmoid colon. Choriocarcinoma is an aggressive tumor characterized by early hematogenous spread and elevated beta-human chorionic gonadotropin (β-hCG) levels. While commonly arising from trophoblastic tissue in the uterus or testes, it may occasionally occur in extragenital locations, including the lungs, brain, and gastrointestinal tract. Primary colorectal choriocarcinoma is extremely rare, with very few cases reported in the literature. Due to its nonspecific presentation and histopathological overlap with other malignancies, diagnosis is often challenging.

Case Presentation

A 30-year-old female presented with a 3-week history of intermittent painless rectal bleeding, associated with fatigue and lightheadedness. She denied any abdominal pain, altered bowel habits, or weight loss. There was no history of prior pregnancies, miscarriages, or gynecological complaints. Menstrual cycles were regular.

Clinical Examination:

• Pale but hemodynamically stable

• Abdomen soft, non-tender, no masses

• Per rectal exam: fresh blood with no palpable mass

Laboratory Investigations:

• Hemoglobin: 7.8 g/dL, low MCV.

• Platelet count: Normal

• Coagulation profile: Normal

• Normal liver and renal function

Imaging and Endoscopy:

• Colonoscopy: Smooth bulge with a mound having friable, ulcerated mass in the distal sigmoid colon extending up to the rectosigmoid junction

• Biopsy: Poorly differentiated carcinoma with multinucleated giant cells and areas of hemorrhage and necrosis.

• Immunohistochemistry: Positive for β-hCG, cytokeratin; negative for CDX2

• CECT Chest/abdomen/pelvis: No evidence of primary gonadal or uterine lesions; localized disease confined to the colon

• Serum β-hCG was very high>1,00,000 units/dL.

Final Diagnosis:

Primary colorectal choriocarcinoma involving the distal sigmoid colon.

Management

The patient underwent surgical resection (low anterior resection with primary anastomosis). Postoperative recovery was uneventful.

Histopathology confirmed choriocarcinoma with negative margins. There was no lymph node involvement. Serum β-hCG levels showed significant decline post-operatively. The patient was referred for adjuvant chemotherapy (EMA-CO regimen: Etoposide, Methotrexate, Actinomycin D, Cyclophosphamide, Vincristine).

Outcome and Follow-Up

At 3-month follow-up, the patient remained symptom-free with normal β-hCG levels and no radiologic evidence of recurrence.

Discussion

Lower Gastrointestinal bleeding due to unusual tumour of trophoblastic origin involving colon is rare. Choriocarcinoma in the colon is uncommon and often mimics more common pathologies such as adenocarcinoma. The absence of a primary gonadal or uterine source and IHC confirmation of trophoblastic origin are critical for diagnosis. Prompt surgical management and appropriate chemotherapy are key for favorable outcomes.

Conclusion

This case emphasizes the need to consider rare malignancies such as choriocarcinoma in young females presenting with lower GI bleeding. Elevated β-hCG levels in such contexts should prompt evaluation for extragenital germ cell tumors.

Key Learning Points:

• Consider β-hCG testing in atypical GI tumors, especially in young females

• Primary colorectal choriocarcinoma is rare but potentially curable if diagnosed early

• Immunohistochemistry plays a crucial role in differentiating this tumor from poorly differentiated carcinomas

References

1. Okubo Y, Fukui I, Sakano Y, Yoshimura K, Maeda H, Yonese J, Yamauchi T, Kawai T, Okumura S, Ishikawa Y: Primary retroperitoneal pure choriocarcinoma. Nihon Hinyokika Gakkai Zasshi 1995, 86:1784–1788.

2. Herai Y, Nishi K, Yamamoto H, Mizuguchi M, Kasahara K, Fujimura M: A case of primary choriocarcinoma of the mediastinum in a Japanese woman. Nihon Kokyuki Gakkai Zasshi 2006, 44:384–388.

3. Chan HS, Humphreys RP, Hendrick EB, Chuang SH, Fitz CR, Becker LE: Primary intracranial choriocarcinoma: a report of two cases and a review of the literature. Neurosurgery 1984, 15:540–545.

4. Harada M, Inoue T, Hamano K: Choriocarcinoma of the sigmoid colon: report of a case. Surg Today 2012, 42:93–96.

5. Metz KA, Richter HJ, Leder LO: Adenocarcinoma of the colon with syncytiotrophoblastic differentiation: differential diagnosis and implications. Path Res Pract 1985, 179:419–424.