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Constipation causing elevated iodine activity in the rectum mimicking thyroid cancer metastases
Bin Liu1, Summer L Kaplan, Hua Yang
1*Department of Nuclear Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, People's Republic of China; and †Department of Radiology, Children's Hospital of Philadelphia, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA.
Clinical Nuclear Medicine
|December 30, 2014
Summary
Constipation can cause intense rectal iodine uptake on imaging, mimicking sacral metastases. Careful patient history and SPECT/CT scans help differentiate this benign finding from malignant lesions.
Area of Science:
- Nuclear medicine
- Gastroenterology
- Oncology
Background:
- Iodine-123 (I-123) or Iodine-131 (I-131) imaging typically shows diffuse gastrointestinal iodine uptake.
- Focal intense iodine activity in the rectum is uncommon and can be mistaken for other pathologies.
Observation:
- Two cases presented with intense, focal iodine activity localized to the rectum.
- This unusual rectal uptake mimicked sacral metastatic lesions on diagnostic imaging.
- The patients' history revealed significant constipation as the underlying cause.
Findings:
- Constipation can lead to concentrated iodine accumulation in the rectum.
- This focal rectal activity can be mistaken for metastatic disease, particularly in the sacrum.
- Distinguishing this benign finding from malignancy is critical for patient management.
Implications:
- Accurate interpretation of radioiodine imaging requires considering potential sources of focal uptake.
- Thorough patient history, including bowel habits, is essential in interpreting incidental findings.
- SPECT/CT imaging aids in differentiating rectal iodine activity from true metastatic lesions, improving diagnostic accuracy.
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