Pancreatic serous cystoadenoma (CSA) showing increased tracer uptake at 68-GaDOTA-peptide Positron Emission Tomography (68Ga-DOTA-peptide PET-CT): a case report

Microcystic Serous Cystadenoma Masquerading as Pancreatic Neuroendocrine Tumor on 99m Tc-HYNIC-TOC SPECT/CT

ABSTRACT

We present 99m Tc-HYNIC-TOC SPECT/CT findings in a case of microcystic serous cystadenoma of the pancreatic head. The pancreatic tumor showed intense 99m Tc-HYNIC-TOC uptake mimicking neuroendocrine tumor on SPECT/CT. This case indicates that microcystic serous cystadenoma should be included in the differential diagnosis of 99m Tc-HYNIC-TOC-avid pancreatic masses.

Increased Uptake in Microcystic Serous Cystadenoma Mimicking Pancreatic Neuroendocrine Tumor on 68 Ga-DOTATATE PET/MRI

ABSTRACT

A 2.6-cm solid cystic lesion in the pancreatic head was found in a 51-year-old woman on CT. A pancreatic neuroendocrine tumor was suspected, and a 68 Ga-DOTATATE PET/MRI was performed, which showed increased tracer uptake in the lesion. However, postsurgical pathologic examination indicated a pancreatic serous cystadenoma. Here, we reported a case of microcystic pancreatic serous cystadenoma that could be misdiagnosed as a pancreatic neuroendocrine tumor on a 68 Ga-DOTATATE PET/MRI.

Prospective Multicentric Assessment of 68Ga-DOTANOC PET/CT in Grade 1-2 GEP-NET

The aim of this multicentric study was to prospectively compare 68Ga-DOTANOC PET/CT versus somatostatin receptor scintigraphy (SRS) with SPECT/CT, combined with multiphasic CT scan and MRI in patients with grade 1 or 2 gastroenteropancreatic neuroendocrine tumors (GEP-NET). Patients with histologically proven grade 1 or 2 GEP-NET with suspicion of recurrence or progression, or with typical aspects of GEP-NET on morphological imaging, were explored with conventional imaging (CI): SRS with SPECT/CT, multiphasic CT scan and/or liver MRI followed by 68Ga-DOTANOC PET/CT. The gold standard was based on histology and imaging follow-up. The data of 105 patients (45 woman and 60 men; median age) were analyzed. 68Ga-DOTANOC PET/CT sensitivity was significantly higher than CI sensitivity in per-patient (98.9% vs. 88.6%, p = 0.016) and per-region (97.6% vs. 75.6%, p < 0.001) analyses, in the detection of the primary (97.9% vs. 78.7%; p = 0.016), peritoneal carcinomatosis (95% vs. 30%, p < 0.001), and bone metastases (100% vs. 33.3%, p = 0.041). 68Ga-DOTANOC PET/CT had an impact on the therapeutic management of 41.9% (44/105) patients compared to decisions based on CI explorations. Our data confirm the superiority of 68Ga-DOTANOC PET/CT over CI in the detection of peritoneal carcinomatosis and bone metastasis, as well as its strong therapeutic impact on the management of patients with grade 1-2 GEP-NETs.

Microcystic serous cystadenoma mimicking pancreatic neuroendocrine neoplasm: report of a resected case with preoperative diagnostic difficulty and review of the literature

Background

Microcystic pancreatic serous cystadenoma (SCA) can be managed without surgery in selected patients. However, the preoperative diagnosis of microcystic SCA remains challenging, and it is potentially misdiagnosed as other pancreatic cystic neoplasms or solid tumors, especially small microcystic SCA.

Case presentation

This was a case of a 27-year-old male patient with microcystic SCA causing difficulty in the differential diagnosis from pancreatic neuroendocrine neoplasm (pNEN). A pancreatic tail mass was incidentally discovered on abdominal ultrasound (US). A contrast-enhanced computed tomography (CT) scan revealed a solid tumor measuring 13 mm with early enhancement in the arterial phase at the pancreatic tail. The tumor showed low intensity on T1-weighted magnetic resonance image, high intensity on T2-weighted image, and a slightly hyperechoic mass on endoscopic US (EUS). EUS-fine needle aspiration (EUS-FNA) did not lead to a definitive diagnosis. The tumor was clinically diagnosed as a pNEN, and a laparoscopic spleen-preserving distal pancreatectomy using the Warshaw technique was performed. The final histopathological diagnosis was microcystic SCA.

Conclusion

Small microcystic SCA is difficult to distinguish from a hypervascular pancreatic tumor such as pNEN on imaging studies, and it is necessary to focus on the tumor echogenicity of EUS to differentiate microcystic SCA from pNEN preoperatively.

Management recommendations for pancreatic manifestations of von Hippel-Lindau disease

Von Hippel-Lindau disease (VHL) is a multineoplasm inherited disease manifesting with hemangioblastoma of the central nervous system and retina, adrenal pheochromocytoma, renal cell carcinoma, pancreatic neuroendocrine tumors and cysts, and neoplasms/cysts of the ear, broad ligament, and testicles. During 2018-2020, the VHL Alliance gathered several committees of experts in the various clinical manifestations of VHL to review the literature, gather the available evidence on VHL, and develop recommendations for patient management. The current report details the results of the discussion of a group of experts in the pancreatic manifestations of VHL along with their proposed recommendations for the clinical surveillance and management of patients with VHL. The recommendations subcommittee performed a comprehensive systematic review of the literature and conducted panel discussions to reach the current recommendations. The level of evidence was defined according to the Shekelle variation of the Grading of Recommendations, Assessment, Development, and Evaluation grading system. The National Comprehensive Cancer Network Categories of Evidence and Consensus defined the committee members' interpretation of the evidence and degree of consensus. The recommendations encompass the main aspects of VHL-related pancreatic manifestations and their clinical management. They are presented in a clinical orientation, including general planning of screening and surveillance for pancreatic neuroendocrine tumors, utility of biochemical biomarkers, the optimal choice for imaging modality, indirect risk stratification, indications for tissue sampling of VHL-related pancreatic neuroendocrine tumors, and interventions. These recommendations are designed to serve as the reference for all aspects of the screening, surveillance, and management of VHL-related pancreatic manifestations.

Variants and Pitfalls of PET/CT in Neuroendocrine Tumors

Management of patients with neuroendocrine neoplasms (NEN) is complex and warrants referral of these patients to high volume centers with appropriate expertise to ensure favorable outcomes. PET/CT becomes increasingly important in every step of their management and outcome. The choice of radiopharmaceutical heavily depends on tumor origin, which is intimately interconnected to embryology, grade and clinical presentation (eg, diagnostic vs theranostic settings). The aim of this review is to describe the role of SSTR, ¹⁸F-FDOPA, and ¹⁸F-FDG-PET imaging in the evaluation of NEN patients. There is emphasis on the main variants, caveats, and pitfalls that can be observed within these modalities. Nuclear physicians must be equipped with the skills to handle potential variants, caveats, and pitfalls that are commonly encountered in NEN imaging, and they should understand the expected imaging features that are encountered across various types of NENs.