Abstract
Primary pancreatic paragangliomas are rare. They are mainly non-functional tumours that lack typical clinical manifestations. Definite diagnosis relies on histopathology and immunohistochemistry, and the main treatment is surgery. We report here a case of primary, non-functional, pancreatic paraganglioma in a 49-year-old woman. The tumour was approximately 5.0 × 3.2 ×4.7 cm in size and located in the pancreatic neck and body. We undertook 3D laparoscopic complete resection of the tumour. The patient developed a pancreatic fistula (biochemical leak) post-surgery, but she recovered and was discharged from hospital 11 days after surgery. We describe this case study and briefly summarize previous related reports.
Introduction
Pheochromocytomas (PCCs) and paragangliomas (PGLs) are rare neuroendocrine tumours and are collectively called pheochromocytoma/paraganglioma (PPGL). 1 Pheochromocytomas are located in adrenal medulla, whereas paragangliomas are formed outside the adrenals, commonly near nerves. 1 All PPGL exhibit a malignant potential. 1 In a population-based setting, standardized incidence rates of PPGL were reported to have increased almost five-fold from 1977 to 2015. 2 The authors suggested that the increase was due to newly diagnosed patients (>50 years) and incidentally discovered PPGLs of small size (<4 cm). However, it could also be due to improved detection of PPGLs due to an increase in imaging. 3 The tumours are slightly more common in women than men with a prevalence of 51–57%, and median age of diagnosis has been estimated to be between 48–55 years. 3 Most PPGLs are discovered following signs and symptoms suspected to be related to catecholamine excess (i.e., paroxysmal hypertension and the classic triad of headaches, sweating and palpitations). 3 However, only one fifth of patients show the classic triad, and some patients are completely asymptomatic. 3
The incidence of PGLs is low and estimated to occur in approximately 2–8 cases/million people, and the tumours can arise in sympathetic and parasympathetic nervous systems. 4 The parasympathetic PGLs are often located in the head and neck, and are mostly non-functional.3,4 The sympathetic PGLs are often located in the abdomen, followed by the chest and pelvis. 5 Abdominal PGLs can produce, store, and secrete catecholamines; and they can produce typical signs and symptoms such as hypertension, palpitations, dizziness, anxiety, blushing, headaches, and sweating. 6
Pancreatic PGLs are extremely rare and to the best of our knowledge, only 53 cases have been reported worldwide over the past 50 years. We present here a case of primary, non-functional, pancreatic PGL and briefly summarize and discuss related reports.
Case Report
A 49-year-old woman presented with a complaint of intermittent epigastric pain which had lasted for one month. The patient had undergone cholecystectomy for gallstones five years previously and had no history of chronic diseases (e.g., hypertension or diabetes). Her personal and family histories were unremarkable. On abdominal examination the patient had abdominal tenderness in the epigastrium.
Routine blood examination, liver, renal, and coagulation function tests, and tumour marker levels (i.e., alpha-fetoprotein, carbohydrate antigen 15-3, carbohydrate antigen 19-9, carbohydrate antigen 72-4, carbohydrate antigen 125, and carcinoembryonic antigen) were within the normal range. Other parameters (i.e., cortisol; angiotensin II; renal activin A; aldosterone; dopamine; adrenaline; noradrenaline) were judged by an endocrinologist, to be within the normal range.
Abdominal computed tomography (CT) showed a pancreatic body tumour approximately 4.6 × 2.9 cm in size and oval in shape with a slightly low-density shadow and clear boundary. Edge enhancement was obvious in the arterial phase and inward-filling enhancement in the portal vein phase. An ectopic pheochromocytoma and splenic arteriovenous compression were considered (Figure 1).

Computed tomography (CT) and magnetic resonance image (MRI) of the tumour: (a) From the CT image, the mass (blue arrow) showed obvious inhomogeneous enhancement in the enhanced arterial phase, (b) From the CT image the mass (blue arrow) showed continuous enhancement in the portal vein stage, (c) An oval, cystic, solid mass (blue arrow) with equal T2 signal in wall and septum, with multiple long T2 hyperintense cystic changes was shown on MRI and (d) The diffusion weighted imaging (Dw1) sequence of the mass (blue arrow) showed a strong signal.
To further define the lesion, magnetic resonance cholangiopancreatography (MRCP) was performed. This showed irregularly long T1 and T2 signal shadows behind the pancreatic body. The diffusion weighted imaging (Dw1) sequence showed a strong signal. Enhancement scanning was uneven, the size was estimated to be 4.3 × 2.7 × 3.9 cm and it was considered a benign neoplastic lesion; the main pancreatic duct was not dilated, and the splenic artery and vein were compressed (Figure 1). Following consultation with endocrinologists and imaging physicians, the final diagnosis was non-functional PGL of the pancreas
The patient was prescribed oral phenbenzylamine 10 mg bd for a month to keep her hormones stable and prevent her blood pressure from increasing during intraoperative tumour removal. On re-examination four weeks later, her levels of methoxy epinephrine, methoxy norepinephrine and 3-methoxytyramine were within normal ranges. The patient then underwent 3D laparoscopic complete resection of the pancreatic mass. During the operation, the soft resected mass was located behind the junction of the pancreatic body and neck and was closely related to the pancreas; the size was approximately 5.0 × 3.2 × 4.7 cm and it was adjacent to the left side of the abdominal aorta, in front of the left renal vein, between the splenic artery and vein (with obvious compression), and close to the confluence of the splenic and portal veins (Figure 2). On the third day post-surgery, a pancreatic fistula (biochemical leak) was detected which was treated conservatively. The patient fully recovered and was discharged from hospital 11 days post-surgery.

Gross examination of the surgical specimen showed the tumour was approximately 5.0 × 3.2 × 4.7 cm in size with a rough texture.
Histological examination post-surgery showed that the tumour cells were separated by capillary nests, forming the classic Zellballen pattern (Figure 3). Immunohistochemistry reports showed SYN (+), CGA (+), CD56 (+), Ki-67 (≤2%), S-100 (−), Sox-10 (+), p53 (−), ERG (−), CD31 (+), CD34 (+), NSE (+), GFAP (+), AE1/3 (−), Cam5.2 (−), GATA3(+). These findings were consistent with the characteristics of PGL Although the patient had no symptoms of hypertension or palpitations, and her blood catecholamine hormones were within normal levels, the postoperative pathological results were consistent with a PGL. Following consultation with endocrinologists and pathologists, the patient was diagnosed as having a non-functional pancreatic PGL. According to the grading system for adrenal PCC and PGL, the total score for this patient was 1, indicating a low-risk grade. 7 Six months following hospital discharge there was no recurrence or evidence of metastasis.

Postoperative histological and immunohistochemical examinations of the resected tumour. Typical “Zellballen” cell nests and lymphocytes were observed.
The case study was approved by Ethics Committee of Qinghai Provincial People's Hospital (2021-wjzdx-18) and signed informed consent was obtained from the patient for publishing her anonymised data. The reporting of this study conforms to CARE guidelines. 8
Discussion
Primary pancreatic PGL is rare and according to our literature review, only 53 cases have been reported worldwide from 1974 to 2021 (Table. 1).4,9–48 Across the 16 men and 37 women the average age was 52 years (range 19–85 years). Of the 53 cases, 28 cases presented with abdominal pain, low back pain, constipation or dyspepsia, 20 were found on physical examination, and only five cases presented with hypertension, palpitation, headache, or fatigue. Twenty-five cases were located in the pancreatic head (including the uncinate process), one in the pancreatic head, neck and body, one in the pancreatic head and neck, two in the pancreatic neck, twelve in the pancreatic body, two in the pancreatic body and tail, eight in the pancreatic tail, and two in the peripancreatic area. Tumour markers did not show any significant abnormalities (data not shown). Six cases were diagnosed as PGL following examination of fine-needle aspiration (FNA) or frozen section (FS)20,27,48 Of the 53 cases, eight had been diagnosed as pancreatic PGL before surgery,13,20,24,27,47,48 twenty-five had been diagnosed as pancreatic neuroendocrine neoplasm (pNEN),4,10–12,15,20,23,29–38,40,41,44–46 and five had been diagnosed as other diseases (i.e., pancreatic cystadenoma, 9 insulinoma, 14 pancreatic cancer, 16 pancreatic pseudocyst, 20 and gastrointestinal stromal tumour (GIST). 42 Forty-seven cases underwent surgery (15 tumour local resection (TLR),9,11,13,15,20,21,25,27,28,38–40,42,47 one case of TLR + splenectomy, 30 10 cases of pancreaticoduodenectomy (PD),10,19,20,22,23,29,31,45,46 one case of PD and hepatectomy, 24 three cases of pylorus preserving pancreaticoduodenectomy (PPPD),14,26,34 one case of PPPD + distal pancreatectomy (DP) + left adrenalectomy (L-ADX), 37 seven cases of DP,4,20,41,43 one case of DP + L-ADX, 16 one case of DP + splenectomy, 33 three cases of resection of the pancreas head (RPH),12,18,44 three cases of central pancreatectomy (CP)32,35,36 and one case of surgery radiotherapy. 17 Six cases did not specify the surgical procedure. Of the 24 studies that specified follow-up times, the range was 1–60 months; only six tumours were reported as functional,13,24,27,43,46 and seven had definite metastases (data not shown).17,20,24,27
Summary of reported cases of pancreatic paraganglioma from the literature (1974 to 2021).
*Location in the pancreas; – not available or unknown.
Abbreviations: 123I-MIBG: metaiodobenzylguanidine; CT: computed tomography; CEUS: contrast-enhanced ultrasound; CP: central pancreatectomy; DP: distal pancreatectomy; DWI, diffusion weighted imaging; EUS: endoscopic ultrasound; F: female; FNA: fine needle aspiration; FS: frozen section; GIST: gastrointestinal stromal tumour; L-ADX: left adrenalectomy; M: male; MRI: magnetic resonance image; NET: neuroendocrine tumour; PCN: pancreatic cystadenoma; PD: pancreaticoduodenectomy; PET: positron emission tomography; pNEN: pancreatic neuroendocrine neoplasm; PPC: pancreatic pseudocyst; p-PGL: paraganglioma of pancreas; PPPD: pylorus preserving pancreaticoduodenectomy; RPH: resection of the pancreas head; TLR: tumour local resection; US: ultrasound; USG: ultrasonogram diagnosis.
Our present case report of a typical, primary, non-functional PGL is consistent with previous findings in that the patient was female and over 40 years of age. 27 In addition, our patient sought medical treatment because of the common PGL symptom of abdominal pain. Although tumour markers were within the normal range and we did not perform an FNA, we made a correct diagnosis before the operation based on typical imaging features and the differential diagnosis for similar diseases. During surgery, we located the tumour behind the pancreatic neck, between the splenic artery and vein, and close to the pancreatic parenchyma. We carefully removed the tumour which was both cystic and solid and approximately 4.5 × 4.7 × 5.1 cm in size. The patient developed a pancreatic fistula (biochemical leak) post-surgery suggesting that the pancreas had been damaged during the procedure. However, she fully recovered following conservative treatment and was discharged from hospital 11 days post-surgery. Pathology and immunohistochemical analysis post-surgery confirmed the diagnosis.
Due to the rarity of the condition, and the fact that most pancreatic PGLs are non-functional and lack typical clinical manifestations, the misdiagnosis rate can be high. Therefore, to improve the understanding of PGL, we have summarized its clinical features and compared them to those of other rare pancreatic tumours (i.e., PPGL, pNEN, serous cystadenoma [SCN], mucinous cystadenomas [MCN], and intraductal papillary mucinous tumour [(IPMN]) (Table 2).49–51 Currently, there is no clear consensus regarding treatment of PGL. However, surgery is the principal treatment modality, supplemented by chemotherapy and radiotherapy for patients with malignant tendencies, but, as demonstrated by our present case study, the choice of surgical procedure should be determined according to the close relationship between the tumour and the pancreatic parenchyma and vessels. Definitive diagnosis of this rare pancreatic tumour depends on postoperative histopathological and immunohistochemical examinations.
Summary of the characteristics of several rare pancreatic tumours.49–51
Abbreviations: BD-IPMN: Branch duct intraductal papillary mucinous tumour; CEA, carcinoembryonic antigen; CgA: Chromogranin A; CT: computed tomography; FAP, Fibroblast-activation protein; IPMN: intraductal papillary mucinous tumour; MCN: mucinous cystadenomas; MD-IPMN: Main duct intraductal papillary mucinous tumour; MRI: magnetic resonance image; NSE: neuron specific enolase; pNEN: pancreatic neuroendocrine neoplasm; p-PGL: paraganglioma of pancreas; PPGL: pheochromocytoma and paraganglioma; SCN: serous cystadenoma.
In summary, pancreatic PGL is a rare entity and so preoperative diagnosis is challenging. The tumour tends to be non-functional and found either incidentally on imaging, or in a patient with abdominal pain. The main treatment is surgical resection and postoperative histopathological and immunohistochemical diagnosis is essential. This present case highlights the importance of a multidisciplinary team approach in the diagnosis of PGL involving radiologists, endocrinologists, pathologists, oncologists, and surgeons.
Footnotes
Acknowledgements
Declaration of conflicting interests
The authors declare that there are no conflicts of interest.
Funding
The authors disclose receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by Health Commission of Qinghai Province (2021-wjzdx-18).
