Rare Synchronous Colonic and Ovarian Carcinomas in a 26 Year Old Female Patient: A Case Report

Background: Synchronous primary malignancies, characterised by the diagnosis of two or more histologically distinct cancers within six months, are uncommon, and data from Sub-Saharan Africa is limited. Their occurrence in young individuals, particularly with colorectal and ovarian primaries, is rare and suggests the possibility of underlying hereditary cancer syndromes. Case Study Presentation: This report describes an uncommon case of synchronous Rectoanal adenocarcinoma and left ovarian endometrioid carcinoma in a 27-year-old Nigerian female, who exhibited altered bowel habits, rectal bleeding, and weight loss. The diagnostic evaluation identified a circumferential rectal tumour, which was histologically confirmed as adenocarcinoma. The patient underwent a diverting colostomy and received neoadjuvant XELOX chemotherapy. Over two months, a rapidly enlarging pelvic mass was observed in her. Surgical exploration identified a large sessile left ovarian tumour, which was histologically confirmed as FIGO Grade 2 endometrioid carcinoma. The postoperative recovery proceeded without complications, and a plan for adjuvant therapy was established. Discussion: This case highlights the diagnostic challenges in distinguishing between metastatic spread and genuine synchronous primaries. The lack of a family history combined with the early age of presentation indicates the potential for sporadic early-onset colorectal cancer or an undiagnosed hereditary syndrome. The dual pathology underscores the necessity for thorough immunohistochemical and genetic assessments, especially in younger patients. In low-resource environments, the delay in diagnosis and restricted access to molecular diagnostics impede the provision of optimal care. Conclusion: The occurrence of synchronous rectal and ovarian malignancies in young females is exceedingly uncommon. This case highlights the necessity of maintaining high clinical suspicion, utilising histopathologic and molecular diagnostics, and implementing genetic screening protocols, especially in Sub-Saharan Africa, to improve early detection and customised management strategies.