Fals
n
Ga-
            
...
Case Report
False positive localization of primary mesenteric
neuroendocrine tumor to the pancreas with
Ga-DOTATATE PETeCT...
ultrasound revealed a spherical hypoechoic mass with
hyperechoic areas in the periphery at the epigastric region,
below an...
The rationale for employment of Ga-DOTA-conjugate pep-
tides in the assessment of SST-receptor (SSTR) expressing NET
relie...
Apollohospitals:http://www.apollohospitals.com/
Twitter:https://twitter.com/HospitalsApollo
Youtube:http://www.youtube.com...
Upcoming SlideShare
Loading in...5
×

False positive localization of primary mesenteric neuroendocrine tumor to the pancreas with Ga-DOTATATE PET–CT changing the surgical management

145

Published on

Neuroendocrine tumors (NETs) are a group of neoplasms that arise from the neural crest. They can be predominantly found in the gastrointestinal tract, pancreas, lung and rarely in the ovary and thymus.

The introduction of β emitting 68Ga-radiolabelled-DOTA peptides in PET–CT for the imaging of NETs has been giving promising results. But, it is worthwhile to know the limitations of using Ga-DOTA peptides to minimize the occurrence of false positives. We report an interesting case of a primary mesenteric neuroendocrine tumor that was misdiagnosed as a nodal secondary from a falsely localized primary pancreatic NET as a result of non-specific physiologic Ga-DOTA uptake in the pancreas. This resulted in an unnecessary distal pancreatectomy.

Published in: Health & Medicine
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
145
On Slideshare
0
From Embeds
0
Number of Embeds
3
Actions
Shares
0
Downloads
3
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

False positive localization of primary mesenteric neuroendocrine tumor to the pancreas with Ga-DOTATATE PET–CT changing the surgical management

  1. 1.                                                                                                   Fals n Ga-                                      se positiv neuroend -DOTAT        ve localiza ocrine tum TATE PET man ation of p mor to th T-CT cha nagement      primary m he pancrea anging the t mesenteric as with e surgical c l
  2. 2. Case Report False positive localization of primary mesenteric neuroendocrine tumor to the pancreas with Ga-DOTATATE PETeCT changing the surgical management Rochita Venkata Ramanan a, *, Manish Chandra Varma b , Arunachalam Pudhiavan a a Department of Radiology, Apollo Hospitals, Chennai, Tamil Nadu, India b Department of Liver Disease and Transplant, Apollo Hospitals, Chennai, Tamil Nadu, India a r t i c l e i n f o Article history: Received 5 April 2014 Accepted 1 May 2014 Available online 24 May 2014 Keywords: Neuroendocrine tumors Pancreas Primary mesenteric Ga-DOTA PETeCT False positive a b s t r a c t Neuroendocrine tumors (NETs) are a group of neoplasms that arise from the neural crest. They can be predominantly found in the gastrointestinal tract, pancreas, lung and rarely in the ovary and thymus. The introduction of b emitting 68 Ga-radiolabelled-DOTA peptides in PETeCT for the imaging of NETs has been giving promising results. But, it is worthwhile to know the limitations of using Ga-DOTA peptides to minimize the occurrence of false positives. We report an interesting case of a primary mesenteric neuroendocrine tumor that was mis- diagnosed as a nodal secondary from a falsely localized primary pancreatic NET as a result of non-specific physiologic Ga-DOTA uptake in the pancreas. This resulted in an unnec- essary distal pancreatectomy. Copyright ª 2014, Indraprastha Medical Corporation Ltd. All rights reserved. 1. Introduction Neuroendocrine tumors (NETs) are a group of neoplasms that arise from the neural crest. They can be predominantly found in the gastrointestinal tract, pancreas, lung and rarely in the ovary and thymus. The introduction of b emitting 68 Ga-radiolebelled-DOTA peptides in PETeCT for the imaging of NETs has been giving promising results. But, it is worthwhile to know the limitations of using Ga-DOTA peptides to minimize the occurrence of false positives. We report an interesting case of a primary mesen- teric neuroendocrine tumor that was misdiagnosed as a nodal secondary from a primary pancreatic NET as a result of non- specific Ga-DOTA uptake in the pancreas. 2. Case report We report the case of a 59-year-old female patient, who pre- sented with complaints of pain in the epigastric region and chest along with dysphagia for two months. An abdominal * Corresponding author. No 34 Srinivasa Moorthy Avenue, Off L B Road, Adyar, Chennai, Tamil Nadu 600020, India. E-mail address: rochitav@yahoo.com (R.V. Ramanan). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/apme a p o l l o m e d i c i n e 1 1 ( 2 0 1 4 ) 1 3 1 e1 3 3 http://dx.doi.org/10.1016/j.apme.2014.05.007 0976-0016/Copyright ª 2014, Indraprastha Medical Corporation Ltd. All rights reserved.
  3. 3. ultrasound revealed a spherical hypoechoic mass with hyperechoic areas in the periphery at the epigastric region, below and close to the pancreatic body. This was followed by a contrast enhanced 160 slice helical CT in the arterial and venous phases. It showed a spherical solid mass with heterogeneous contrast enhancement adherent to the duodeno-jejunal flexure and at one point infiltrating the wall of the jejunum. The mass showed few calcific foci and hypodense areas within it. The mass was separate from the pancreas and no focal lesion was found in the pancreas other than a small cyst in the body. A diagnosis of gastrointestinal stromal tumor was made on the CT scan. (Figs. 1 and 2) Guided biopsy of the mass revealed a NET. It was then decided to perform a Ga-DOTATATE PETeCT. This showed an increased tracer uptake by the mass with a SUVmax of 40. In addition, a small area of increased tracer uptake was also seen in the pancreatic tail region with a SUVmax of 4.5. (Fig. 3) No corresponding lesion could be identified on the CT scan. Nevertheless a final diagnosis of a primary pancreatic NET with adjacent nodal secondaries was made. Accordingly, the surgical management was changed from only a wide resection of the mass to a subtotal distal pancreatectomy with en bloc removal of the mass with spleen, third and fourth parts of the duodenum and the proximal jejunum. (Fig. 4). Histopathology of the mesenteric mass established it to be a well-differentiated primary mesenteric NET. The resected pancreatic parenchyma was normal and no lesion corre- sponding to the increased tracer uptake in the PETeCT ex- amination could be identified. 3. Discussion Somatostatin is a small, cyclic neuropeptide that is present in neurons and endocrine cells. It has a high density in the brain, peripheral neurons, endocrine pancreas and gastrointestinal tract. Fig. 1 e Oblique volume rendered CT reconstruction in the arterial phase reveals a mass inferior to and separate from the pancreas. Fig. 2 e Oblique volume rendered CT reconstruction in the venous phase reveals the mass close to the first loop of the jejunum and separate from the pancreas. P-Body pancreas, H-Head pancreas, St-Stomach. Fig. 3 e Ga DOTATATE PETeCT reveals a focal increased uptake in the tail pancreas marked within cursors. a p o l l o m e d i c i n e 1 1 ( 2 0 1 4 ) 1 3 1 e1 3 3132
  4. 4. The rationale for employment of Ga-DOTA-conjugate pep- tides in the assessment of SST-receptor (SSTR) expressing NET relies on the high affinity of these compounds for SSTR. Ga-DOTA-TATE presents a predominant affinity for SSTR 2. Although PET with the newer Ga-DOTA-conjugate peptides like Ga-DOTA-TOC, Ga-DOTA-NOC, Ga-DOTA-TATE has brought about dramatic improvements in spatial resolution compared to the older I-123 and In-111 labeled studies, there are some limitations in organs with a higher physiological uptake. The pancreas shows variable uptake of Ga-DOTA- conjugate peptides. Though all 5 subtypes of SSTR are pre- sent in the pancreas, the subtype-2 receptor is commonly found and is located in the islets. Accumulation of islets in one pancreatic region, frequently the pancreatic head, may cause an increased uptake mimicking a tumor. Any area of focal increased uptake that is not physiological and has a high SUV is considered diagnostic for tumors. The median SUVmax values are 59.4 Æ 48.6 for pancreatic NETs, 26.5 Æ 18.6 for gastrointestinal NETs and 20.4 Æ 13.5 for lung NETs.1 Castellucci et al, in their study have found that in cases of extra-pancreatic NET, several patients showed increased pancreatic DOTA uptake, either focal or diffuse.2 Since this uptake remained stable over a period of follow up, they concluded that this uptake was likely due to physiologic variability in SSTR expression by pancreatic endocrine cells and to variability in their anatomic distribution in the organ. Awareness of this physiologic variability in SSTR expression and endocrine cell distribution within the pancreas is impor- tant especially to avoid misdiagnosis of a tumor. In our case, this kind of misinterpretation led to an un- necessary resection of the tail pancreas. The fact that the NET was closely related to the tail pancreas also contributed to misdiagnosis. This can be avoided by noting the SUVmax value of physiologic uptake within normal pancreatic tissue, which is significantly lower than that of NET. This case highlights the phenomenon of non-specific physiological Ga- DOTATATE uptake by pancreatic tissue, which can result in false positive interpretations and the method to prevent such an error. Conflicts of interest The authors declare no conflict of interest whatsoever arising out of the publication of this manuscript. r e f e r e n c e s 1. Campana Davide, Ambrosini Valentina, Pezzilli Raffaele, et al. Standardized uptake values of 68 Ga-DOTANOC PET: a promising prognostic tool in neuroendocrine tumors. J Nucl Med. 2010;51:353e359. 2. Castellucci Paolo, Pou Ucha Javier, Fuccio Chiara, et al. Incidence of increased 68 Ga-DOTANOC uptake in the pancreatic head in a large series of extrapancreatic NET patients studied with sequential PET/CT. J Nucl Med. 2011;52(6):886e890. Fig. 4 e Surgical specimen reveals the mass (M), distal pancreas (P), Duodenum (D), Proximal jejunum (J) and spleen (Sp). a p o l l o m e d i c i n e 1 1 ( 2 0 1 4 ) 1 3 1 e1 3 3 133
  5. 5. Apollohospitals:http://www.apollohospitals.com/ Twitter:https://twitter.com/HospitalsApollo Youtube:http://www.youtube.com/apollohospitalsindia Facebook:http://www.facebook.com/TheApolloHospitals Slideshare:http://www.slideshare.net/Apollo_Hospitals Linkedin:http://www.linkedin.com/company/apollo-hospitals Blog:Blog:http://www.letstalkhealth.in/

×