Intrapancreatic Accessory Spleen Research Articles

Intrapancreatic accessory spleen: there can be smoke without fire.

Case 1: A 69-year-old male underwent magnetic resonance imaging (MRI) to evaluate hepatic hemangiomas that incidentally revealed a homogeneous hypervascular solid nodule (19 mm) in pancreatic tail. Differential diagnosis included neuroendocrine tumor (NET). Normal chromogranin A and CA19.9 levels. PET-68Ga-DOTANOC scan showed pancreatic tail enhancement consistent with NET. Suspicion of neoplasia persisted after two Endoscopic Ultrasounds with Fine-Needle Aspiration without neoplastic cells. Consequently, distal pancreatectomy was performed, revealing an accessory intrapancreatic spleen. Case 2: A 77-year-old female with dyspepsia performed an abdominal CT followed by MRI and both revealed a solid nodule (11.7 mm) in pancreatic tail with regular margins, suggestive of accessory spleen or pancreatic neoplasia. EUS confirmed a hypoechoic, homogeneous nodule consistent with accessory spleen (11.7mm). A scintigraphy using fragile erythrocytes (4) confirmed intrapancreatic accessory spleen, which requires no treatment.

Dynamic 68Ga-DOTA0-Tyr3-octreotate positron emission tomography-computed tomography for the evaluation of pancreatic neuroendocrine tumors: a pilot study.

68Ga-DOTA0-Tyr3-octreotate (68Ga-DOTATATE) is a radiolabeled somatostatin analog used for the diagnosis of pancreatic neuroendocrine tumors (pNETs), and standardized uptake value (SUV) measurements for therapeutic monitoring is recommended. However, changes in net influx rate (Ki) may better reflect treatment effects than may those of the SUV. The aim of this study was to investigate the value of dynamic 68Ga-DOTATATE positron emission tomography-computed tomography (PET-CT) in the evaluation of pNETs. Dynamic PET-CT scans over 60 min were acquired for 7 patients with localized pancreatic mass before surgery. Maximal and mean SUV (SUVmax and SUVmean) were measured in tumors and normal pancreatic body as reference tissue (RT). Time-activity curves (TACs) were extracted from tumors and RT. A 2-tissue compartment model was used to calculate the rate constants K1, k2, and k3 (min-1); Ki (mL/g/min); and K1:k2 ratio. The following statistical tests were used to evaluate the results: the Shapiro-Wilk, Student t test, Mann-Whitney, Spearman, and Pearson rank correlation tests. Among 6 patients, 8 primary tumors were histopathologically proven to be pNETs. Moreover, 6 lesions with high uptake of 68Ga-DOTATATE showed an ascending TAC pattern, while 2 lesions with no or low uptake showed a descending TAC pattern. The mean SUVmax and SUVmean of pNETs were 46.4±40.2 (range, 3.9-109.9) and 21.9±16.0 (range, 0.5-42.8), respectively, which were significantly higher than the SUVmax of 4.2±0.6 (range, 3.1-4.9) and the SUVmean of 2.7±1.0 (range, 1.4-3.6) for the RT (P=0.021 and P=0.036), respectively. The Ki of pNETs was statistically higher than that of the RT [pNET: 0.366±0.372 (range, 0.019-0.992); RT: 0.060±0.017 (range, 0.04-0.08); P=0.036]. The mean K1:k2 ratio in pNETs was 12-fold higher than that of RT (6.06 vs. 0.50). In pNETs, there was a positive correlation between SUVmax and Ki (r=0.952; P<0.001) and between SUVmean and Ki (r=0.905; P=0.002). Another patient was diagnosed with intrapancreatic accessory spleen. The uptake of 68Ga-DOTATATE by pNETs can be explained by its high Ki value and K1:k2 ratio. Dynamic 68Ga-DOTATATE PET-CT can serve as a potential tool for evaluating pNETs and support the further assessment of a larger cohort of patients.

Rare Solid Pancreatic Lesions on Cross-Sectional Imaging.

Several solid lesions can be found within the pancreas mainly arising from the exocrine and endocrine pancreatic tissue. Among all pancreatic malignancies, the most common subtype is pancreatic ductal adenocarcinoma (PDAC), to a point that pancreatic cancer and PDAC are used interchangeably. But, in addition to PDAC, and to the other most common and well-known solid lesions, either related to benign conditions, such as pancreatitis, or not so benign, such as pancreatic neuroendocrine neoplasms (pNENs), there are solid pancreatic lesions considered rare due to their low incidence. These lesions may originate from a cell line with a differentiation other than exocrine/endocrine, such as from the nerve sheath as for pancreatic schwannoma or from mesenchymal cells as for solitary fibrous tumour. These rare solid pancreatic lesions may show a behaviour that ranges in a benign to highly aggressive malignant spectrum. This review includes cases of an intrapancreatic accessory spleen, pancreatic tuberculosis, solid serous cystadenoma, solid pseudopapillary tumour, pancreatic schwannoma, purely intraductal neuroendocrine tumour, pancreatic fibrous solitary tumour, acinar cell carcinoma, undifferentiated carcinoma with osteoclastic-like giant cells, adenosquamous carcinoma, colloid carcinoma of the pancreas, primary leiomyosarcoma of the pancreas, primary and secondary pancreatic lymphoma and metastases within the pancreas. Therefore, it is important to determine the correct diagnosis to ensure optimal patient management. Because of their rarity, their existence is less well known and, when depicted, in most cases incidentally, the correct diagnosis remains challenging. However, there are some typical imaging features present on cross-sectional imaging modalities that, taken into account with the clinical and biological context, contribute substantially to achieve the correct diagnosis.

Diagnostic accuracy of apparent diffusion coefficient to differentiate intrapancreatic accessory spleen from pancreatic neuroendocrine tumors

Diagnostic accuracy of apparent diffusion coefficient to differentiate intrapancreatic accessory spleen from pancreatic neuroendocrine tumors

Intrapancreatic accessory spleen in slaughtered pigs: investigations on occurrence and histomorphology

Intrapancreatic accessory spleen in slaughtered pigs: investigations on occurrence and histomorphology

The Role of MRI in the Diagnosis of Solid Pseudopapillary Neoplasm of the Pancreas and Its Mimickers: A Case-Based Review with Emphasis on Differential Diagnosis.

Solid pseudopapillary neoplasm (SPN) is rare pancreatic tumor occurring most commonly in young females. The typical imaging appearance of SPN is of well-defined, encapsulated, and large heterogeneous tumors, consisting of solid and cystic components due to various degrees of intralesional hemorrhage and necrosis. However, atypical imaging presentation in the form of small solid tumors or uniformly cystic lesions might also be seen, which can be explained by specific pathological characteristics. Other imaging features such as a round shape, the absence of main pancreatic duct dilatation, and slow growth, in combination with vague symptoms, favor the diagnosis of SPNs. Nevertheless, the radiological findings of SPN might overlap with other solid and cystic pancreatic neoplasms, such as neuroendocrine tumors, serous and mucinous neoplasms, and even small pancreatic adenocarcinomas. In addition, a few benign non-tumorous conditions including walled-of-necrosis, and intrapancreatic accessory spleen may also pose diagnostic dilemmas simulating SPNs on imaging studies. The aim of this manuscript is to provide a comprehensive overview of the typical and atypical imaging features of SPNs and to describe useful tips for differential diagnosis with its potential mimickers.

The Rate of Avoidable Pancreatic Resections at a High-Volume Center: An Internal Quality Control and Critical Review.

The incidence of benign diseases among pancreatic resections for suspected malignancy still represents a relevant issue in the surgical practice. This study aims to identify the preoperative pitfalls that led to unnecessary surgeries at a single Austrian center over a twenty-year period. Patients undergoing surgery for suspected pancreatic/periampullary malignancy between 2000 and 2019 at the Linz Elisabethinen Hospital were included. The rate of "mismatches" between clinical suspicion and histology was considered as primary outcome. All cases that, despite that, fulfilled the indication criteria for surgery were defined as minor mismatches (MIN-M). Conversely, the true avoidable surgeries were identified as major mismatches (MAJ-M). Among the 320 included patients, 13 (4%) presented with benign lesions at definitive pathology. The rate of MAJ-M was 2.8% (n = 9), and the most frequent causes of misdiagnoses were autoimmune pancreatitis (n = 4) and intrapancreatic accessory spleen (n = 2). In all MAJ-M cases, various mistakes within the preoperative workup were detected: lack of multidisciplinary discussion (n = 7, 77.8%); inappropriate imaging (n = 4, 44.4%); lack of specific blood markers (n = 7, 77.8%). The morbidity and mortality rates for mismatches were 46.7% and 0. All avoidable surgeries were the result of an incomplete pre-operative workup. The adequate identification of the underlying pitfalls could lead to minimize and, potentially, overcome this phenomenon with a concrete optimization of the surgical-care process.

Intrapancreatic Accessory Spleen as a Differential Diagnosis of Tail Pancreatic Tumor

Intrapancreatic Accessory Spleen as a Differential Diagnosis of Tail Pancreatic Tumor

Intrapancreatic accessory spleen

Introduction: Intrapancreatic accessory spleen (IPAS) is a congenital focus of healthy splenic tissue present outside of the splenic parenchyma. There are numerous locations for IPAS and they are usually found incidentally. The location of ectopic splenic tissue is important as it can often mimic as a neoplasm, most commonly neuroendocrine tumor (NET) due to similar imaging characteristics on nuclear imaging and computed tomography (CT) scan. We report on the finding of an IPAS in the tail of the pancreas for which fine needle aspiration was performed. Patient concerns: A 66-year-old man with past medical history of prostate cancer managed with brachytherapy presented to his urologist for workup of persistently elevated prostate specific antigen. He underwent a nuclear medicine whole body scan which revealed uptake in the pancreatic tail for which follow up CT was recommended. The patient was seen by the gastroenterology and a CT scan was obtained. CT revealed a 4 cm × 3 cm isoenhancing mass in the tail of the pancreas without invasion to surrounding structures nor communication with the pancreatic ducts. No lymphadenopathy was noted. Intervention: The patient subsequently underwent endoscopic ultrasound (EUS) with fine needle aspiration (FNA) of the mass. EUS revealed a hypoechoic, oval, mass-like structure in the distal pancreatic tail measuring ~20 mm × 20 mm in maximal cross-sectional diameter. FNA of the mass was performed. Diagnosis: Cytopathology of the specimen revealed small mature lymphocytes and vessels suggestive of IPAS. Outcome: The patient remained asymptomatic through the duration of the workup. Lessons: All enhancing pancreatic lesions require further workup to rule out malignancy. Typically, patients undergo scintigraphy for further evaluation or FNA biopsy via EUS for confirmation. Currently, there are no established serum markers or radiographic findings with adequate specificity for diagnosing IPAS. It is important to recognize the impact of incidental findings as they frequently require further testing and often result in procedural intervention. IPAS is often confused with NET, frequently necessitating tissue sampling. While the prevalence of intrapancreatic accessory spleen is higher than initially thought, contrary to NET it carries no inherent risk unless its location compromises vital structures. This highlights the importance of recognizing this anomaly.

Intrapancreatic accessory spleens in African swine fever infection of wild boar (Sus scrofa).

Intrapancreatic accessory spleen (IPAS) is one of the most frequent congenital splenic anomalies in humans; however, studies in veterinary medicine are scarce. This study aimed to describe the macroscopic, histopathological and immunohistochemical features of 11 suspected cases of IPAS in wild boar piglets of 3-4 months old. Seven of the 11 animals were immunised with a low virulence isolate of African swine fever virus (ASFV) and subsequently challenged with a highly virulent ASFV isolate (LVI-HVI group). The remaining four animals were exclusively infected with a highly virulent isolate of ASFV (HVI group). Grossly, lesions comprised focal or multifocal reddish areas of variable shape, located on the surface of the pancreatic tail or within the parenchyma. Histological and immunohistochemical studies (anti-CD79 and CD3) confirmed the presence of IPAS in eight of the 11 cases. IPAS shared the same histological structure and alterations as those observed in the original spleen. The immunohistochemical study against ASFV revealed the presence of VP72+ cells in both the spleen and IPAS of seven of the eight piglets. The results of this study describe for the first time the presence of IPAS in ASFV infection of wild boar (Sus scrofa) regardless the isolate and suggest that the infection may induce the development of ectopic splenic tissue due to an increased demand for phagocytic cells from the reticuloendothelial system. However, further studies are needed to understand the immunological mechanisms that trigger the formation of these accessory organs.

Epidermal Cyst in an Intrapancreatic Accessory Spleen

A 59-year-old asymptomatic woman with no disease history presented to our institution for investigation of a pancreatic tail mass. Hematological parameters were within normal ranges, including serum carcinoembryonic antigen levels and carboxyhydrate antigen 19-9. Computed tomography revealed a strongly enhanced solid peripheral mass with an intracystic component in the pancreatic tail (Figure A, arrow). Magnetic resonance imaging revealed a cystic lesion on the T2 image surrounded by a solid component with density and intensity levels similar to those in the spleen parenchyma (Figure B, arrow). Endoscopic ultrasonography showed a solid hyperechoic 20-mm mass and an intracystic hypoechoic component showing stronger enhancement by Sonazoid (MSD Inc) than the pancreatic parenchyma (Figure C, arrow). Laparoscopic distal pancreatectomy was used for diagnosis. Pathological examination revealed a white and red sinus of the ectopic spleen in the pancreatic tail, with a unilocular cyst lined with stratified squamous epithelium, indicating an epidermal cyst in the intrapancreatic accessory spleen (Figure D, arrows). Most epidermal cysts in the intrapancreatic accessory spleen cases are found incidentally, typically as single monolobular cystic lesions in the pancreatic tail with a thickened cystic wall or solid components identical in density to the spleen on imaging examinations, making a definite preoperative diagnosis extremely difficult, resulting in unnecessary surgical intervention.

Histological and immunohistochemical analysis of epithelial cells in epidermoid cysts in intrapancreatic accessory spleen

Epidermoid cysts in intrapancreatic accessory spleen (ECIPAS) are a rare lesion. Its pathogenesis, including the origin of cystic epithelium, is not well established. We aimed to elucidate new aspects of the pathological features of ECIPAS to clarify its pathogenesis.Six cases of ECIPAS were included in this study. As well as histopathological analysis, to elucidate the features and nature of cystic epithelial cells, immunohistochemical analysis including Pbx1 and Tlx1 and imaging mass spectrometry was performed.Histologically, the cysts were covered by either monolayered or multilayered epithelium. Immunohistochemistry revealed that the epithelial cells in multilayered epithelium exhibited different attributes between the basal and superficial layers. Few epithelial cells had abundant clear cytoplasm and were immunohistochemically positive for adipophilin, suggesting lipid-excreting function. The intracystic fluid contained cholesterol clefts and foamy macrophages, and imaging mass spectrometry revealed the accumulation of lipids. Immunohistochemical analysis indicated that the epithelial cells were positive for Pbx1 in some cases.Novel histological features of epithelial cells of ECIPAS were indicated. Although more cases need to be evaluated, we propose that the cause of ECIPAS may be different from that of pancreatic ductal origin. J. Med. Invest. 70 : 251-259, February, 2023.

The efficacy of endoscopic ultrasound for preoperative diagnosis of epidermoid cyst in an intrapancreatic accessory spleen: a case report

The efficacy of endoscopic ultrasound for preoperative diagnosis of epidermoid cyst in an intrapancreatic accessory spleen: a case report

S1756 Intrapancreatic Accessory Spleen, an Important Consideration That Can Reduce Invasive Interventions in the Evaluation of Pancreatic Lesions

S1756 Intrapancreatic Accessory Spleen, an Important Consideration That Can Reduce Invasive Interventions in the Evaluation of Pancreatic Lesions

Unmasking the Intrapancreatic Accessory Spleen

Despite the availability of various diagnostic studies including CT, MRI, nuclear medicine images, and endoscopic ultrasound, the differentiation of Intrapancreatic Accessory Spleen (IPAS) from pancreatic neuroendocrine tumor remains challenging. We present the case of a 40-year-old male with an incidentally found intrapancreatic lesion with indeterminate imaging diagnosis. A CT demonstrated accessory spleens at the splenic hilum. Laparoscopic distal pancreatectomy with splenectomy was performed. Pathology resulted with benign IPAS. Despite indeterminate imaging, a high suspicion for IPAS should be maintained in patients with other accessory spleens.

Asymtomatic Mass In The Tail Of The Pancreas: Intrapancreatic Accessory Spleen (IPAS).

We present a 48-year-old male patient with a mass in the tail of the pancreas on abdominal ultrasonography. The lesion was suspicious for a well-differentiated pancreatic neuroendocrine tumor and spleen preserved distal pancreatectomy surgery was performed. It was diagnosed as intrapancreatic accessory spleen (IPAS) after pathological examination. Accessory spleen is not an infrequent congenital entity caused by the localization of normal splenic tissue in ectopic regions. As it is known, an accessory spleen is a benign entity and does not require surgical treatment or follow-up when detected. However, it is important to recognize IPAS tissue as it may mimic a pancreatic neoplasia when it is located in the pancreas. In this article, we discuss the differential diagnostic possibilities of the IPAS entity.

AB154. SOH22ABS135. Laparoscopic distal pancreatectomy and splenectomy for an intrapancreatic accessory spleen—a case report and review of the literature

Background: This case serves as a reminder to consider ectopic splenic tissue in the differential diagnosis of pancreatic masses. The literature shows a lack of awareness and overtreatment of this condition due to clinical and radiologic concern for malignancy, namely neuroendocrine tumours, metastases.

Intrapancreatic accessory spleen: Findings on MR imaging and CT

BackgroundAlthough intrapancreatic accessory spleen (IPAS) are infrequently noticed radiologically, they have been reported up to 2, 8% in Autopsies. The aims of this study were to describe the imaging characteristics of IPAS using computed tomography (CT) and/or magnetic resonance imaging (MRI) to prevent an unnecessary surgery. Materials and methodsDuring last 7 years, 5 consecutive patients with incidental intrapancreatic accessory spleen (IPAS) on the tail of pancreas which radiologically mimicked a neuroendocrine pancreatic tumor, surgically treated in our university hospital. Preoperative CT studies (4 of 5 patients) and MRI (2 of 5 patients, one patient had both CT and MR images), operation reports and pathological diagnoses were analyzed retrospectively. For each lesion, images were analyzed based on the characteristic signal intensities on MRI or density of the lesion on CT images and presence of contrast enhancement. Pathologic correlation was available for the lesions. ResultsThe female-to-male ratio was 2:3, with a mean age of 56 years (age range, 42–72 years). Incidental lesion findings were due to imaging studies using magnetic resonance imaging and/or computed tomography. In all the patients there was just one lesion on the tail of pancreas. On all the MR images (2 of 5 patients), a focal pancreatic lesion that was in compared to the rest of pancreas hypointense on T1-weighted sequences were detected, these lesions were hyperintesne on T2-weighted sequences; and enhanced more than the pancreas tissue in contrast enhanced series; however, the lesions were with the same intensity in compared to spleen in all the sequences. The enhancement pattern of the lesion was evaluated as serpiginous on early postgadolinium sequences. On all CT studies (4 of all 5 patients), there were no detectable lesions on pre-contrast series; however, on all arterial and venous series lesions were hyperdens in contrast to the rest of pancreas. The lesions had the same density of spleen in all series. In both MRI and CT images there were No adenopathy in the abdomen. Tumor size was among min. 9 × 12 mm to max. 16 × 18 mm. Pathological findings were intrapancreatic accessory spleen (IPAS) in all the cases. One patient had a pathological finding of Leiomyoma of the stomach too. ConclusionRadiologists and Surgeons should be aware that an incidental finding of a subtle well-marginated, rounded solitary lesion on the tail of pancreas on the CT or MR images which matches the density/or intensity of the spleen on all phases/ or sequences could be an intrapancreatic accessory spleen (IPAS); Therefore, an IPAS has to be excluded in asymptomatic patients with a lesions in the pancreatic tail before unnecessary surgery.

Intrapancreatic accessory spleen mimicking pancreatic insulinoma with intrapancreatic metastasis in a cat.

An 11-year-old neutered male Domestic Shorthair cat presented with a 3-month history of hypoglycemia, two episodes of seizure, and intermittent tick-like signs. Serum biochemistry revealed severe hypoglycemia associated with high insulin concentrations. Dynamic abdominal computed tomography (CT) indicated two pancreatic masses, which were enhanced most during the late arterial phase but had different degrees and variations of attenuation. Partial pancreatectomy was performed. Histopathology and immunohistochemistry confirmed that one mass was an insulinoma and the other was an ectopic splenic tissue, consistent with the differences in imaging findings. When an intrapancreatic lesion with hyper-attenuation on dynamic abdominal CT is detected, not only insulinoma or metastasis of malignancies but also intrapancreatic accessory spleen (IPAS) should be considered as differential diagnoses.

S1613 Intrapancreatic Accessory Spleen: A Concerning Mass With Reassuring Pathology

Introduction: Intrapancreatic accessory spleen (IPAS) is a congenital focus of healthy splenic tissue present outside of the splenic parenchyma. There are numerous locations for IPAS and they are usually found incidentally. The location of ectopic splenic tissue is important as it can often mimc as a neoplasm, most commonly neuroendocrine tumor (NET) due to similar imaging characteristics on nuclear imaging and CT scan. We report on the finding of an IPAS in the tail of the pancreas for which fine needle aspiration was performed. Case Description/Methods: A 66-year-old man with past medical history of prostate cancer managed with brachytherapy presented to his urologist for workup of persistently elevated prostate specific antigen. He underwent a nuclear medicine whole body scan which revealed uptake in the pancreatic tail for which follow up computed tomography (CT) was recommended. The patient was seen by the gastroenterology and a CT scan was obtained. CT revealed a 4cm x 3cm isoenhancing mass in the tail of the pancreas without invasion to surrounding structures nor communication with the pancreatic ducts. No lymphadenopathy was noted. The patient subsequently underwent endoscopic ultrasound (EUS) with fine needle aspiration (FNA) of the mass. EUS revealed a hypoechoic, oval, mass-like structure in the distal pancreatic tail measuring ∼20mm x 20mm in maximal cross-sectional diameter. FNA of the mass was performed. Cytopathology of the specimen revealed small mature lymphocytes and vessels suggestive of IPAS. The patient remained asymptomatic through the duration of the workup. Discussion: All enhancing pancreatic lesions require further workup to rule out malignancy. Typically, patients undergo scintigraphy for further evaluation or FNA biopsy via EUS for confirmation. Currently, there are no established serum markers or radiographic findings with adequate specificity for diagnosing IPAS. It is important to recognize the impact of incidental findings as they frequently require further testing and often result in procedural intervention. IPAS is often confused with NET, frequently necessitating tissue sampling. While the prevalence of intrapancreatic accessory spleen is higher than initially thought, contrary to NET it carries no inherent risk unless its location compromises vital structures. This highlights the importance of recognizing this anomaly.Figure 1.: Panel A: CT Image including mass in pancreas, Panel B: EUS with FNA of mass Panel C: H&E stain of pathology specimen.