Misinterpretation of [۹۹mTc]Tc-Octreotide scan due to accessory spleen in a patient with well-differentiated neuroendocrine tumor: A case report

ABSTRACTA ۷۶-year-old woman with a medical history of type II diabetes and hypertension underwent an upper gastrointestinal endoscopy due to persistent dyspepsia and epigastric pain for the past six months. During the procedure, the gastroenterologist identified multiple small polyps in the antrum and distal pylorus, which were subsequently removed. The polyps were sent to pathology, and the final report revealed a diagnosis of a well-differentiated (low-grade) neuroendocrine tumor. Afterward, the patient was referred to nuclear medicine for a whole-body scan using [۹۹mTc]Tc-Octreotide. The resulting images demonstrated a focal increased activity in the upper left quadrant of the abdomen. To clarify the diagnosis, SPECT/CT imaging was employed to evaluate the area of concern, which showed a focal uptake in the basal part of the left lung, raising suspicion for lung metastasis. However, a subsequent diagnostic CT demonstrated an accessory spleen in that region. It was later determined that there was misregistration in the SPECT/CT study, which is a common finding in this region. This case underscores the potential for misinterpretation of imaging results, where uptake in an accessory spleen can be mistaken for metastatic disease.

کلیدواژه ها:

Neuroendocrine tumor ، [۹۹mTc]Tc-Octreotide scan ، Accessory spleen ، SPECT/CT imaging ، False-positive uptake