Rectal adenocarcinoma with germ cell elements treated with chemotherapy

Area of Science:

• Gastrointestinal Oncology
• Reproductive Endocrinology
• Pathology

Background:

• Rectal adenocarcinoma is a common malignancy.
• Germ cell tumors typically occur in the gonads.
• Mixed germ cell tumors are exceedingly rare in extragonadal sites.

Observation:

• A unique case of rectal adenocarcinoma with concurrent endodermal sinus tumor and choriocarcinoma is presented.
• Markedly elevated serum levels of alpha-fetoprotein and human chorionic gonadotropin were detected.
• Immunoperoxidase staining confirmed the neoplastic tissue as the source of these tumor markers.

Findings:

• The presence of both adenocarcinoma and germ cell elements (endodermal sinus tumor, choriocarcinoma) within the same rectal tumor.
• Correlation of elevated serum alpha-fetoprotein and human chorionic gonadotropin with the germ cell components.
• Development of extensive hepatic metastases attributed to the choriocarcinoma component.

Implications:

• This case represents the first reported instance of a rectal adenocarcinoma with these specific germ cell elements.
• Highlights the importance of considering extragonadal germ cell components in rectal tumors, especially with elevated tumor markers.
• The findings underscore the aggressive nature of choriocarcinoma, leading to rapid metastasis and fatal hemorrhage despite chemotherapy.