Synchronous Primary Malignancies: Incidental Detection of Ascending Colon Adenocarcinoma During Staging of Invasive Ductal Carcinoma of the Breast

Abstract

Multiple primary malignant neoplasms (MPMNs) are defined as two or more distinct tumors in the same individual. Synchronous breast and colon cancers are infrequent and present management challenges due to the lack of standardized guidelines. We report a 73-year-old woman presenting with a right breast mass, subsequently diagnosed as Grade 2 invasive ductal carcinoma. Staging CT incidentally revealed right colon wall thickening, and colonoscopy with biopsy confirmed moderately differentiated invasive adenocarcinoma. Following neoadjuvant chemotherapy, she underwent simultaneous radical mastectomy with axillary lymph node dissection and right hemicolectomy. Postoperative recovery was uneventful. Adjuvant chemoradiation was administered per multidisciplinary team (MDT) recommendation. Synchronous breast and colon cancers pose unique diagnostic and treatment planning challenges. MDT collaboration is crucial for personalized treatment strategies and optimized outcomes in these complex cases.

Keywords: breast cancer; colon cancer; multidisciplinary team meeting; multiple primary malignant neoplasms; synchronous primary malignancies.

Figure 1

Histopathological examination of the breast biopsy revealing a Grade 2 invasive ductal carcinoma according to the Scarff–Bloom–Richardson grading system.

Figure 2

Colonoscopy showing an ulcerated, budding, circumferential, and nonobstructive lesion in the right colon, located distal to the cecum and extending approximately 10 cm in length.

Figure 3

Histopathological examination of the colonic tumor biopsy revealing an invasive, moderately differentiated adenocarcinoma.

Figure 4

Modified radical mastectomy (left side) and right hemicolectomy (right side) specimens.