Case Author(s): Jayson R. St. Jacques,M.D. and Farrokh Dehdashti,M.D. , 10/18/02 . Rating: #D3, #Q4

Diagnosis: Neuroendocrine tumor in mediastinum.

Brief history:

74 year old woman with a left paratracheal mass.


3 plane FDG-PET images.

View main image(pt) in a separate image viewer

View second image(ot). Octreotide spect 3 plane views.

View third image(ct). Axial CT of the chest images.

Full history/Diagnosis is available below

Diagnosis: Neuroendocrine tumor in mediastinum.

Full history:

74 year old woman with a left paratracheal mass that initially presented as difficulty in swallowing. Patient underwent CT scan of the chest followed by a transesophageal biopsy. The biospy demonstated a non-small cell lung cancer of neuroendocrine type.

PET scanning requested for initial staging.


3.7 mCi F-18 Fluorodeoxyglucose for FDG-PET, and 4.98 mCi In-111 pentetreotide i.v. (Octreotide)


FDG-PET imaging demonstrated mildly increased uptake in the region of the paraesophageal mass noted on chest CT with no evidence of metastatic disease. Octreotide imaging was suggested as FDG-PET imaging has reduced sensitivity for neuroendocrine tumors compared to Octreotide.

Octeotide imaging demonstrates increased uptake within the same lesion without evidence of metastatic disease.


Neuroendocrine tumors are typically well differentiated with rare mitotic rate. The nuclear medicine study of choice for evaluating these tumors is In-111 Octeroscan. FDG-PET is only useful in evaluating less differentiated neuroendocrine tumors with high proliferative activity. Therefore, FDG-PET should be performed only if In-111 Octeroscan is negative.

Reference: Adams et al., Eur J Nucl Med 1998; 25:79-83.

ACR Codes and Keywords:

References and General Discussion of PET Tumor Imaging Studies (Anatomic field:Lung, Mediastinum, and Pleura, Category:Neoplasm, Neoplastic-like condition)

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Case number: pt086

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