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December 2022, Volume 72, Issue 12

IMAGING CORNER

Neuroendocrine liver metastases — ‘doughnut box sign’ on SPECT/CT

Neil Thomson  ( Nuclear Medicine Department, Kent and Canterbury Hospital, East Kent Hospitals University Foundation NHS Trust, Canterbury, UK. )
Carolina Pina  ( Nuclear Medicine Department, Kent and Canterbury Hospital, East Kent Hospitals University Foundation NHS Trust, Canterbury, UK. )
Humayun Bashir  ( Nuclear Medicine Department, Kent and Canterbury Hospital, East Kent Hospitals University Foundation NHS Trust, Canterbury, UK. )
Gordon Ellul  ( Nuclear Medicine Department, Kent and Canterbury Hospital, East Kent Hospitals University Foundation NHS Trust, Canterbury, UK. )

Abstract

A 76 year old patient was referred for Indium111 Octreotide scan to look for primary tumour and extent of neuroendocrine metastases. Indium 111 Octreotide scan showed a liver packed with centrally necrotic metastases like doughnuts packed in a box. No primary lesion was identified in this scan.

Keywords: Doughnut box sign, Neuroendocrine tumours, Indium111 Octreotide scan.

A 76 year old patient was referred for Indium 111 Octreotide scan to look for primary tumour and extent of neuroendocrine (NE) metastases. The 111 Octreotide showed a liver packed with metastases like doughnuts packed in a box (Image). No primary lesion was identified in this scan. Pubmed search1-3 reveals 49 responses to a search for 'doughnut sign' in the publication titles for various imaging modalities, organs and pathologies. In scintigraphy a 'doughnut' invariably represents a lesion with a central area of necrosis surrounded by the tumour (e.g. octreotide positive somatostatin expressing neuroendocrine liver metastases) or normal tissue. The volume of scintigraphically avid disease has important implications for the diagnostic sensitivity and potential therapeutic applications. 'Tumour sink effect,' can result in reduced sensitivity to localize the primary tumour site. However, in therapeutic applications 'tumour sink effect' is considered a favourable feature which helps reduce the physiological uptake of high energy radioligands in normal tissue and organs and provides room for using higher doses for maximum tumouricidal impact.4 In neuroendocrine tumours 12% to 74% of patients can present with liver metastases with a negative impact on prognosis. The primary site can remain unknown after work up in 12-22% of patients diagnosed with NE while it is only <5% of cancers of unknown primary (CUP). There is a role for debulking, however, a liver packed with metastases is a candidate for chemotherapy or radioligand therapy rather than surgery.4,5

 

 

 

 

References

 

1.       Lu SJ, Gnanasegaran G, Buscombe J, Navalkissoor S. Single photon emission computed tomography/computed tomography in the evaluation of neuroendocrine tumours: a review of the literature. Nucl Med Commun. 2013; 34:98-107.

2.       Deppen SA, Blume J, Bobbey AJ, Shah C, Graham MM, Lee P, Delbeke D, Walker RC. 68Ga-DOTATATE Compared with 111In-DTPA-Octreotide and Conventional Imaging for Pulmonary and Gastroenteropancreatic Neuroendocrine Tumors: A Systematic Review and Meta-Analysis. J Nucl Med. 2016; 57:872-8.

3.       Bozkurt MF, Virgolini I, Balogova S, Beheshti M, Rubello D, Decristoforo C, Ambrosini V, Kjaer A, Delgado-Bolton R, Kunikowska J, Oyen WJG, Chiti A, Giammarile F, Sundin A, Fanti S. Guideline for PET/CT imaging of neuroendocrine neoplasms with 68Ga-DOTA-conjugated somatostatin receptor targeting peptides and 18F-DOPA. Eur J Nucl Med Mol Imaging. 2017; 44:1588-1601.

4.       Beauregard JM, Hofman MS, Kong G, Hicks RJ. The tumour sink effect on the biodistribution of 68Ga-DOTA-octreotate: implications for peptide receptor radionuclide therapy. Eur J Nucl Med Mol Imaging. 2012; 39:50-6.

5.       Gangi A, Howe JR. The Landmark Series: Neuroendocrine Tumor Liver Metastases. Ann Surg Oncol. 2020; 27:3270-3280

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