Figure 1
SRS (SPECT/CT) with EDDA-HYNIC-TOC-Tc99m
Overexpression of somatostatin receptors in the primary tumour, apparently located at the ileocaecal valve.
Well-differentiated neuroendocrine tumour of the ileum
SectionAbdominal imaging
Case TypeClinical Cases
AuthorsCoelho ML1, Dias N2, Curvo-Semedo L3, Moreira A4; Caseiro-Alves F3
Connected authors
64 years, male
Clinical History
64-year-old male patient, referred to our institution for surgical treatment of a neuroendocrine tumour apparently located on the ileocaecal valve found during colonoscopic screening examination.
The patient had no signs or symptoms of carcinoid syndrome.
The laboratory tests showed elevated serum chromogranin A - 32 nmol / L (<6.0).
The patient had no signs or symptoms of carcinoid syndrome.
The laboratory tests showed elevated serum chromogranin A - 32 nmol / L (<6.0).
Imaging Findings
Somatostatin Receptor Scintigraphy (SPECT/CT) with EDDA-HYNIC-TOC-Tc99m showed a focal area of somatostatin receptor overexpression, apparently located in the ileocaecal valve. No other focal hyperfixations were identified.
The staging CT demonstrated a well-defined, noncalcified, sessile polyp, measuring 34x32x21mm, apparently located at the ileocaecal valve. After contrast injection, the polyp showed intense enhancement in the arterial phase, slightly less prominent during the portal-venous phase. Some adenopathy - enlarged and hyperenhancing mesenteric lymph nodes - were also visible in the same CT study.
After surgery, the follow-up CTs, Somatostatin Receptor Scintigraphies and recently a Ga-68 DOTATOC PET / CT showed no signs of recurrence or metastasis until that moment.
The staging CT demonstrated a well-defined, noncalcified, sessile polyp, measuring 34x32x21mm, apparently located at the ileocaecal valve. After contrast injection, the polyp showed intense enhancement in the arterial phase, slightly less prominent during the portal-venous phase. Some adenopathy - enlarged and hyperenhancing mesenteric lymph nodes - were also visible in the same CT study.
After surgery, the follow-up CTs, Somatostatin Receptor Scintigraphies and recently a Ga-68 DOTATOC PET / CT showed no signs of recurrence or metastasis until that moment.
Discussion
Neuroendocrine neoplasms are epithelial neoplasms with predominant neuroendocrine differentiation. They are divided into well-differentiated and poorly-differentiated, depending on the grade of the tumour, mitotic index and calculation of Ki-67 index [1].
Neuroendocrine neoplasms of the lower jejunum and ileum constitute up to 23-28% of all gastrointestinal neuroendocrine tumours and are multi-centric in 26-30% [2, 3]. Most are well-differentiated (low grade (ENETS G1), with a mitotic count <2/10HPF or Ki-67 < 2% and intermediate grade (ENETS G2), with a mitotic count 2–20/10HPF or Ki-67 2–20%) [2]. They can also be non-functioning (70-80%) or functioning (20-30%, most of them with liver metastasis) [2].
Neuroendocrine neoplasms of the lower jejunum and ileum most commonly occur between the 6th and 7th decade of life [2]. Non-functioning tumours are diagnosed later during the course of the disease, commonly in the investigation of an occult primary tumour, in patients with liver metastasis, or incidentally during an endoscopic study [2], as in this case.
Symptoms of non-functioning tumours can include vague abdominal pain and intermittent intestinal obstruction [2, 4].
CT: Hypervascular wall thickening, mass lesion or polyp, with marked enhancement in arterial phase, that becomes less prominent in the portal-venous and equilibrium phases [3, 4]. Non-functioning tumours are usually larger and may have calcifications. Mesenteric bulky ganglionar metastases are also common and are frequently associated with desmoplastic reaction, creating retraction of the mesentery and mesenteric masses with a sunburst appearance and calcifications (<70%) [2]. Bowel loops may be displaced, unusually separated, or sharply bent by the mesenteric retraction. Encasement of mesenteric vessels can lead to chronic ischaemia. Frequently small functioning primary tumours not visible on CT present with these masses [2]. Hepatic, pulmonary and osteoblastic skeletal metastasis can appear in advanced disease.
Somatostatin receptor scintigraphy: Hyperfixation is seen in 80-90% of patients with small intestine neuroendocrine neoplasms [2]. It may also detect metastatic adenopathy and lung, breast, bone or brain metastases [2]. Fusion with hybrid equipment (SPECT/CT) is preferred and can often provide a more accurate morphological guidance [5]. PET with 68Ga-labeled somatostatin analogs can detect 30% more lesions than scintigraphy [2, 5].
PET/CT with FDG is useful in poorly differentiated neuroendocrine carcinomas and can detect localized dedifferentiation in well-differentiated advanced tumours [5].
Treatment of localized locoregional disease of well-differentiated non-functioning tumours:
- Curative surgery (bowel resection with regional mesenteric lymphadenectomy) [2]
5-year survival rate [2]:
- localized disease - 65–75%
- non-localized disease - 50%.
- liver metastasis - 18–32%
Neuroendocrine neoplasms of the lower jejunum and ileum constitute up to 23-28% of all gastrointestinal neuroendocrine tumours and are multi-centric in 26-30% [2, 3]. Most are well-differentiated (low grade (ENETS G1), with a mitotic count <2/10HPF or Ki-67 < 2% and intermediate grade (ENETS G2), with a mitotic count 2–20/10HPF or Ki-67 2–20%) [2]. They can also be non-functioning (70-80%) or functioning (20-30%, most of them with liver metastasis) [2].
Neuroendocrine neoplasms of the lower jejunum and ileum most commonly occur between the 6th and 7th decade of life [2]. Non-functioning tumours are diagnosed later during the course of the disease, commonly in the investigation of an occult primary tumour, in patients with liver metastasis, or incidentally during an endoscopic study [2], as in this case.
Symptoms of non-functioning tumours can include vague abdominal pain and intermittent intestinal obstruction [2, 4].
CT: Hypervascular wall thickening, mass lesion or polyp, with marked enhancement in arterial phase, that becomes less prominent in the portal-venous and equilibrium phases [3, 4]. Non-functioning tumours are usually larger and may have calcifications. Mesenteric bulky ganglionar metastases are also common and are frequently associated with desmoplastic reaction, creating retraction of the mesentery and mesenteric masses with a sunburst appearance and calcifications (<70%) [2]. Bowel loops may be displaced, unusually separated, or sharply bent by the mesenteric retraction. Encasement of mesenteric vessels can lead to chronic ischaemia. Frequently small functioning primary tumours not visible on CT present with these masses [2]. Hepatic, pulmonary and osteoblastic skeletal metastasis can appear in advanced disease.
Somatostatin receptor scintigraphy: Hyperfixation is seen in 80-90% of patients with small intestine neuroendocrine neoplasms [2]. It may also detect metastatic adenopathy and lung, breast, bone or brain metastases [2]. Fusion with hybrid equipment (SPECT/CT) is preferred and can often provide a more accurate morphological guidance [5]. PET with 68Ga-labeled somatostatin analogs can detect 30% more lesions than scintigraphy [2, 5].
PET/CT with FDG is useful in poorly differentiated neuroendocrine carcinomas and can detect localized dedifferentiation in well-differentiated advanced tumours [5].
Treatment of localized locoregional disease of well-differentiated non-functioning tumours:
- Curative surgery (bowel resection with regional mesenteric lymphadenectomy) [2]
5-year survival rate [2]:
- localized disease - 65–75%
- non-localized disease - 50%.
- liver metastasis - 18–32%
Differential Diagnosis List
Well-differentiated non-functioning neuroendocrine tumour of the ileum
NEUROENDOCRINE CARCINOMA - Neuroendocrine carcinomas are frequently positive in 18F-FDG PET-CT studies. Neuroendocrine carcinoma expression of somatostatin receptors is variable [5].
GASTROINTESTINAL STROMAL TUMOUR (GIST) - GISTs are hypervascular intramural masses usually larger than neuroendocrine tumours. Calcifications or mesenteric masses are unusual features [3] and they don\'t express high levels of somatostatin receptors on SR
KAPOSI SARCOMA - rare in patients without AIDS and usually shows more ulceration [3]. High expression of somatostatin receptors on SRS or PET/CT DOTA-NOC-Ga68 is not a feature of the disease.
Final Diagnosis
Well-differentiated non-functioning neuroendocrine tumour of the ileum
References
[1] Klimstra DS, Modlin IR, Coppola D, Lloyd RV, Suster S (2010) The Pathologic Classification of Neuroendocrine Tumors. Pancreas 39(6):707-712 (PMID: 20664470)
[2] Eriksson B, Klöppel G, Krenning E, et al (2008) Consensus Guidelines for the Management of Patients with Digestive Neuroendocrine Tumors – Well-Differentiated Jejunal-Ileal Tumor/Carcinoma. Neuroendocrinology 87(nov):8–19 (PMID: 18097129)
[3] Lee NM, Kim S, Kim GH, et al (2010) Hypervascular Subepithelial Gastrointestinal Masses: CT-Pathologic Correlation. RadioGraphics 30(7):1915–1934 (PMID: 21057127)
[4] Chang S, Choi D, Lee SJ, et al. (2007) Neuroendocrine Neoplasms of the Gastrointestinal Tract: Classification, Pathologic Basis, and Imaging Features. Radiographics 27(6):1667–1679 (PMID: 18025510)
[5] Binderup T, Knigge U, Loft A, et al (2010) Functional Imaging of Neuroendocrine Tumors: A Head-to-Head Comparison of Somatostatin Receptor Scintigraphy, 123I-MIBG Scintigraphy, and 18F-FDG PET. Journal of Nuclear Medicine 51 (5): 704-712 (PMID: 20395333)
Case information
| URL: | https://www.eurorad.org/case/11458 |
| DOI: | 10.1594/EURORAD/CASE.11458 |
| ISSN: | 1563-4086 |
Figure 2
Axial unenhanced CT image
Noncalcified, sessile polypoid mass apparently located at the ileocaecal valve.
Figure 3
Axial enhanced CT image - Arterial Phase
Intense homogeneous enhancing of the polyp in the arterial phase.
Figure 4
Axial enhanced CT image - Portal-venous phase
Slightly less prominent enhancement of the polyp in the portal-venous phase.
Figure 5
Axial enhanced CT image - Arterial phase
Mesenteric locoregional adenopathy, with 17x13mm, showing heterogeneous enhancement in arterial phase.
SRS (SPECT/CT) with EDDA-HYNIC-TOC-Tc99m
Overexpression of somatostatin receptors in the primary tumour, apparently located at the ileocaecal valve.
Nuclear Medicine Department, Centro Hospitalar e Universitário de Coimbra
Nuclear Medicine Department, Centro Hospitalar e Universitário de Coimbra
Axial unenhanced CT image
Noncalcified, sessile polypoid mass apparently located at the ileocaecal valve.
Radiology Department of Centro Hospitalar e Universitário de Coimbra
Radiology Department of Centro Hospitalar e Universitário de Coimbra
Axial enhanced CT image - Arterial Phase
Intense homogeneous enhancing of the polyp in the arterial phase.
Radiology Department of Centro Hospitalar e Universitário de Coimbra
Radiology Department of Centro Hospitalar e Universitário de Coimbra
Axial enhanced CT image - Portal-venous phase
Slightly less prominent enhancement of the polyp in the portal-venous phase.
Radiology Department of Centro Hospitalar e Universitário de Coimbra
Radiology Department of Centro Hospitalar e Universitário de Coimbra
Axial enhanced CT image - Arterial phase
Mesenteric locoregional adenopathy, with 17x13mm, showing heterogeneous enhancement in arterial phase.
Radiology Department of Centro Hospitalar e Universitário de Coimbra
Radiology Department of Centro Hospitalar e Universitário de Coimbra