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Monday Poster Session

Category: Colon

P2593 - Metastatic Colon Cancer With DNMT3A Mutation

Monday, October 27, 2025
10:30 AM - 4:00 PM MT
Location: Exhibit Hall
Marina Khan, MD1, Faisal S. Shariff, MD2, Ateeb Parvez, MBBS3, Zarmina Khan, DMD4, Danae Hamouda, MD5
1University of Toledo Medical Center, Toledo, OH; 2University of Toledo Medical Center, Sylvania, OH; 3St. Elizabeth's Medical Center, Boston University School of Medicine, Quincy, MA; 4UF Health Jacksonville, Jacksonville, FL; 5University of Toledo Medical Center, Hematology and Oncology fellowship Program Director, Toledo, OH

Introduction: DNMT3A mutations disrupt DNA methylation in colon cancer, driving tumorigenesis via epigenetic dysregulation. These alterations are linked to aggressive disease and poor prognosis, highlighting potential for targeted therapies

Case Description/

Methods:

A 52-year-old woman with a history of systemic lupus erythematosus (SLE) and end-stage renal disease (status post living donor transplant on immunosuppression) presented with significant weight loss and lethargy. Laboratory workup revealed iron deficiency anemia, for which endoscopy and colonoscopy were performed, revealing masses in the stomach, duodenum, and ascending colon. Pathology confirmed a poorly differentiated adenocarcinoma, and genetic profiling identified a DNMT3A Q886 variant. She was subsequently hospitalized due to confusion and hemoptysis. Brain MRI showed a 5 mm enhancing lesion in the frontal lobe with minimal surrounding edema. Further imaging revealed bilateral pulmonary nodules, celiac lymphadenopathy, and extensive muscular involvement. During her hospital stay, she developed septic and hemorrhagic shock, requiring ICU admission, vasopressors, and broad-spectrum antibiotics. She received three cycles of CAPEOX chemotherapy, followed by palliative radiotherapy targeting muscular metastases. Brain metastasis was managed with steroids and stereotactic radiosurgery.

Discussion:

This case highlights an exceptionally rare presentation of DNMT3A-mutated colorectal cancer (CRC) with metastases to the brain, duodenum, stomach, and thoracic muscle. DNMT3A mutations, typically seen in hematologic malignancies, are uncommon in CRC and associated with aggressive disease and poor prognosis. Brain metastases occur in < 3% of CRC cases, while duodenal involvement is even rarer. The patient’s rapid decline and unusual metastatic pattern suggest a potential link between DNMT3A and atypical dissemination. Given her critical illness, treatment was palliative. This case highlights the need for vigilant screening in high-risk patients and comprehensive genomic profiling to uncover rare variants that may influence disease behavior. Further research is warranted to explore DNMT3A’s role in CRC metastasis.


Figure: Foci of abnormal uptake within the stomach and duodenum.


Figure: Single rounded enhancing focus in the right frontal lobe with adjacent edema concerning for metastatic disease.

Disclosures:
Marina Khan indicated no relevant financial relationships.
Faisal Shariff indicated no relevant financial relationships.
Ateeb Parvez indicated no relevant financial relationships.
Zarmina Khan indicated no relevant financial relationships.
Danae Hamouda indicated no relevant financial relationships.

Marina Khan, MD1, Faisal S. Shariff, MD2, Ateeb Parvez, MBBS3, Zarmina Khan, DMD4, Danae Hamouda, MD5. P2593 - Metastatic Colon Cancer With DNMT3A Mutation, ACG 2025 Annual Scientific Meeting Abstracts. Phoenix, AZ: American College of Gastroenterology.