An unusual presentation of accessory spleen mimicking a pancreatic neoplastic lesion in a splenectomized patient: A case report

Accessory spleen is a relatively common occurrence. However, an intrapancreatic accessory spleen can get hypertrophied following splenectomy and rarely mimic a pancreatic neoplasm leading to misdiagnosis. Here we present a 64-year-old male who had undergone left radical nephrectomy and splenectomy for renal cell carcinoma 14 years back, presenting with upper abdominal discomfort. He was found to have a mass in the pancreatic tail on imaging, suggesting an intrapancreatic neoplastic lesion. After a multidisciplinary team decision based on contrast-enhanced computed tomography and magnetic resonance imaging, he underwent an uncomplicated distal pancreatectomy, and the histology revealed an intrapancreatic accessory spleen. Contrast-enhanced computed tomography, magnetic resonance imaging, and positron emission tomography alone is not specific enough to confidently differentiate an accessory spleen preoperatively. Nuclear scintigraphy fused with contrast-enhanced computed tomography provides more specific and better anatomically localized evidence. Ultrasound-guided fine needle sampling showing lymphocytes with subsets of histiocytes, plasma cells, and immunohistochemistry showing CD8 positivity can be used to guide the definitive diagnosis. Differentiating an accessory spleen from a pancreatic neoplasm may be challenging preoperatively. Accessory spleen needs to be considered in the differential diagnosis of upper abdominal masses especially in patients who have undergone splenectomy.

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.

Intrapancreatic accessory spleen mimicking pancreatic NET: can unnecessary surgery be avoided?

Pancreatic nodules are frequently found incidentally and often pose a diagnostic and therapeutic challenge when surgery is considered. We present the case of a 66-year-old cirrhotic patient with a pancreatic nodule with signal intensity and contrast enhancement pattern suggestive for a non-functional neuroendocrine lesion. A ⁶⁸Gallium-DOTATOC PET-CT scan revealed a correspondent focal tracer uptake in the pancreatic tail. After distal pancreatectomy, the specimen surprisingly revealed intrapancreatic splenic tissue. Nuclear imaging has previously been reported to produce a false-positive result for the presence of a neuroendocrine tumor when an intrapancreatic accessory spleen is present. This case reminds us of the diagnostic pitfalls in pancreatic nodules, to consider a broad differential diagnosis and to remain critical before referring the patient for surgery.

Epidermoid cyst within an intrapancreatic accessory spleen exhibiting abrupt changes in serum carbohydrate antigen 19-9 level: a case report

Background

Epidermoid cyst within an intrapancreatic accessory spleen (ECIAS) is a rare disease. While the detection of solid components relevant to an accessory spleen is a key diagnostic finding, the differential diagnosis between ECIAS and malignant tumors is difficult without resection in patients with no other findings of an accessory spleen.

Case presentation

A 73-year-old male was found to have an elevated carbohydrate antigen (CA) 19-9 level (95 U/mL) at an annual checkup, and a cystic lesion in the pancreatic tail was located by abdominal ultrasound. Abdominal magnetic resonance imaging (MRI) revealed a multicystic mass, 24 mm in diameter, which exhibited varying intensities on T2-weighted images. There were no findings suggesting solid components on contrast-enhanced computed tomography and magnetic resonance imaging. Re-evaluation of serum CA 19-9 level revealed a rapid increase to 901 U/mL, which declined to 213 U/mL 3 weeks later. Ruling out the lesion’s malignant potential was difficult, and the patient underwent distal pancreatectomy with splenectomy. Histological findings revealed an ECIAS including multiple cysts, with the mucinous component of each cyst exhibiting different stages of biological reaction; one ruptured cyst exhibited inflammatory changes.

Conclusions

Careful observation for changes in serum CA 19-9 level and MRI findings might facilitate the diagnosis of ECIAS without a solid component by imaging studies.

Endoscopic ultrasonography elastography in the diagnosis of intrapancreatic ectopic spleen: A case report

BACKGROUND

Intrapancreatic accessory spleen (IPAS) mimics a pancreatic neoplasm on imaging studies, and due to the lack of radiological diagnostic criteria, patients undergo unnecessary distal pancreatectomies. Endoscopic ultrasonography (EUS) is a reliable and efficient diagnostic modality for pancreatic diseases. However, no EUS criteria have been established for IPAS. We present the EUS-elastography image of IPAS, which may minimize the chance of misdiagnosis in the future.

CASE SUMMARY

A 50-year-old man was referred for an EUS evaluation after computed tomography showed a hypervascular enhanced mass in the tail of the pancreas, which indicated a neuroendocrine neoplasm. EUS elastography demonstrated that the lesion of interest covered no more than 25% of the region of interest. The patient underwent distal pancreatectomy. However, the resected tissue was evaluated, and the patient was finally diagnosed with IPAS.

CONCLUSION

IPAS should be considered in patients with suspected pancreatic neuroendocrine tumors of the pancreatic tail before surgery is performed. The differentiation between IPAS and pancreatic neuroendocrine tumors can be demonstrated using EUS-elastography.

Malignant Transformation of an Epidermoid Cyst in an Intrapancreatic Accessory Spleen: A Case Report

A 33-year-old man was evaluated because of an incidentally found cyst in the pancreatic tail, which was first seen 6 years ago. The cyst was a unilocular cystic mass, 13.0 cm in diameter, and had increased in size in last 2 months. On F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT), the cystic wall showed increased FDG uptake. The patient underwent distal pancreatectomy with suspicion of mucinous cystic neoplasm of the pancreas. The mass turned out to be a squamous carcinoma arising from an epidermoid cyst in an intrapancreatic accessory spleen (ECIPAS). FDG PET/CT may assist recognition of a potential malignant lesion arising from an ECIPAS.

Superparamagnetic iron-oxide-enhanced diffusion-weighted magnetic resonance imaging for the diagnosis of intrapancreatic accessory spleen

PURPOSE

To evaluate the diagnostic performance of superparamagnetic iron-oxide (SPIO)-enhanced diffusion-weighted image (DWI) for distinguishing an intrapancreatic accessory spleen from pancreatic tumors.

MATERIALS AND METHODS

Twenty-six cases of intrapancreatic accessory spleen and nine cases of pancreatic tail tumors [neuroendocrine tumor (n = 8) and pancreatic adenocarcinoma (n = 1)] were analyzed. Two blind reviewers retrospectively reviewed the SPIO-enhanced magnetic resonance imaging (MRI) scans. The lesion visibility grades were compared and the diagnostic performance of SPIO-enhanced DWI was compared to those of SPIO-enhanced T2WI and T2*WI with the use of a receiver operating characteristic (ROC) analysis.

RESULTS

The grade of lesion visibility was the highest on DWI [mean ± standard deviation (SD): 2.8 ± 0.3] followed by T2WI (2.3 ± 0.7, p < 0.001) and T2*WI (2.1 ± 0.7, p < 0.0001). Reviewers 1 and 2 correctly characterized the presence or absence of SPIO uptake in 34 of 35 cases (97.1%) on DWI, 24 (68.6%) and 25 (71.4%) cases on T2WI, respectively, and 16 (45.7%) and 17 (48.6%) cases on T2*WI. The area under the ROC curve (AUC) of DWI was 0.974 and 0.989 for reviewers 1 and 2, respectively. For Reviewer 1, the AUC of DWI was significantly higher than that of T2*WI (0.756, p < 0.01), although it was not significantly different from that of T2WI (0.868, p = 0.0857). For Reviewer 2, the AUC of DWI was significantly higher than those of T2WI (0.846, p < 0.05) and T2*WI (0.803, p < 0.01).

CONCLUSION

The diagnostic performance of SPIO-enhanced DWI was better than those of SPIO-enhanced T2*WI and T2WI for the diagnosis of intrapancreatic accessory spleen.

Intrapancreatic accessory spleen false positive to 68Ga-Dotatoc: case report and literature review

Background

Intrapancreatic accessory spleen (IPAS) is an uncommon finding of pancreatic mass. Differential diagnosis with pancreatic tumor, especially with non-functional neuroendocrine tumor (NF-NET), may be very hard and sometimes it entails unnecessary surgery. A combination of CT scan, MRI, and nuclear medicine can confirm the diagnosis of IPAS. 68-Ga-Dotatoc PET/CT is the gold standard in NET diagnosis and it can allow to distinguish between IPAS and NET.

Case presentation

A 69-year-old man was admitted to our hospital for an incidental nodule in the tail of the pancreas with focal uptake of 68-Ga-dotatate at PET/CT. NET was suspected and open distal splenopancreatectomy was performed. Pathologic examination revealed an IPAS.

Conclusion

This is the second IPAS case in which a positive 68Ga-Dotatoc uptake led to a false diagnosis of pancreatic NET. Here is a proposal of a literature review.

Epidermoid cyst in intrapancreatic accessory spleen: A systematic review

BACKGROUND/OBJECTIVES

Due to its rarity, epidermoid cyst in intrapancreatic accessory spleen (ECIPAS) is still a diagnostic dilemma during clinical practice. The aim of this review was to summarize the epidemiologic features and management of ECIPAS.

METHODS

MEDLINE and EMBASE were searched for English articles reporting on ECIPAS up to April 30th, 2018 following the methodology suggested by the PRISMA guidelines. Categorical variables were reported as frequency and percentage. Continuous variables were reported as median (range).

RESULTS

A total of 56 patients from 47 full articles were included for the final data synthesis. More than half of the ECIPASs (59%) were found incidentally. The female/male ratio was 1.33. ECIPAS is typically a single mono-/multi-lobular cystic lesions in the pancreatic tail with thickened cystic wall or various amount of solid component which had identical density/signal to the spleen on imaging examinations. The cyst is filled with serous or non-serous fluid. Recognition of the surrounding ectopic splenic tissue is the key point to diagnose ECIPAS. However, no preoperative examination was able to make a definite diagnosis. Almost all the patients (96%) received surgical treatment, due to the suspicion of pancreatic malignant or potentially malignant cystic tumor, especially mucinous cystic neoplasm (MCN).

CONCLUSIONS

Although seldom encountered, ECIPAS should be considered as a differential diagnosis for pancreatic cystic lesions, especially when solid component was detected. As a benign disease, unnecessary surgery should be avoided. Because it is difficult to make a definite diagnosis preoperatively by one single examination, multiple modalities may be required.

Laparoscopic Resection of an Epithelial Cyst in an Intrapancreatic Accessory Spleen

An epithelial cyst in an intrapancreatic accessory spleen (ECIAS) is rare. We herein report a case of a patient with ECIAS who underwent laparoscopic surgery. A 57-year-old woman was referred to our hospital because of a pancreatic tail tumor. She was asymptomatic, and a physical examination revealed no remarkable abnormalities. The levels of the tumor marker carbohydrate antigen 19-9 (CA19-9) and s-pancreas-1 antigen (SPan-1) were elevated. Ultrasonography showed a well-defined homogeneous cystic tumor. Computed tomography showed a well-demarcated cystic tumor in the pancreatic tail. Magnetic resonance imaging showed that the cystic tumor exhibited low intensity on T1-weighted images and high intensity on T2-weighted images. The cystic tumor was diagnosed as mucinous cystic neoplasm preoperatively. The patient underwent laparoscopic spleen-preserving distal pancreatectomy. A histopathological examination revealed the cyst wall to be lined by stratified squamous epithelium within splenic parenchyma, and the ultimate diagnosis was ECIAS. The postoperative course was uneventful, and the patient was discharged on postoperative day 12. ECIAS is very difficult to diagnose preoperatively. Laparoscopic surgery is a safe and minimally invasive procedure for patients with difficult-to-diagnose pancreatic tail tumor suspected of having low-grade malignancy.

Ectopic spleen and liver hemangioma mimicking metastatic pancreatic neuroendocrine tumor

Pancreatic tumors comprise benign lesion and malignant lesion, most importantly pancreatic adenocarcinoma, acinar cell carcinoma, neuroendocrine carcinoma or metastasis. Surgical resection provides the only chance for cure for malignant pancreatic tumors. In some cases, surgical resection is performed because a malignant lesion is suspected, however, histopathological examinations eventually reveal a benign lesion. Here, we report the case of a 49-year-old woman, who was initially diagnosed with a neuroendocrine tumor of the pancreas with metastasis to the liver. The patient underwent distal pancreatectomy and atypical liver resection. Surprisingly, however, histopathological examination revealed an intrapancreatic accessory spleen (IPAS) of the pancreatic tail as well as liver hemangioma. This unique case report highlights the impact of extensive preoperative examinations to differentiate benign and malignant pancreatic lesions and, possibly, prevent patients from unnecessary surgery.

Diffusion-weighted MRI: usefulness for differentiating intrapancreatic accessory spleen and small hypervascular neuroendocrine tumor of the pancreas

BACKGROUND

Image findings of intrapancreatic accessory spleen (IPAS) can closely resemble those of neuroendocrine tumor (NET) of the pancreas.

PURPOSE

To investigate the usefulness of diffusion-weighted imaging (DWI) for differentiating IPAS from small (≤3 cm) hypervascular NET of the pancreas.

MATERIAL AND METHODS

The visually assessed signal intensity of pancreatic lesions compared with the spleen on DWI (b value of 1000 s/mm(2)) and the apparent diffusion coefficient (ADC) values were compared in 25 patients with IPAS and 31 patients with small hypervascular NET. Two blinded radiologists independently rated their confidence in differentiating the two conditions and compared the diagnostic performance of contrast-enhanced magnetic resonance imaging (CE-MRI) alone with that of combined CE-MRI and DWI.

RESULTS

The isointensity of the pancreatic lesions compared with the spleen on DWI was more frequently observed in IPAS than in NET (92% vs. 12.9%, P < 0.001). The mean ADC value was significantly lower in IPAS than in NET (0.90 × 10(-3) mm(2)/s vs. 1.44 × 10(-3) mm(2)/s, P < 0.001). The sensitivity and specificity of ADC quantification for differentiating the two conditions when using 1.07 × 10(-3) mm(2)/s as the cut-off value were 96% and 93.5%, respectively. For both readers, the area under the receiver operating characteristic curve and accuracy in differentiating the two conditions of combined CE-MRI and DWI were significantly greater than those of CE-MRI alone (P ≤ 0.039).

CONCLUSION

Visual assessment of DWI and ADC quantification were useful in differentiating IPAS from small hypervascular NET of the pancreas.

Post-splenectomy intrapancreatic accessory spleen mimicking endocrine tumor of the pancreas

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The first case of IPAS arising after splenectomy.

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The IPAS has similar features of pancreatic neuroendocrine tumor on images.

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Typical pathologic data and characteristics of IPAS were presented and described.

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A brief review of IPAS was included.

INTRODUCTION

Intrapancreatic accessory spleen is an uncommon congenital abnormality of the spleen with no indication for surgical intervention. Among the few cases reported, IPAS coexisted with a normal spleen. We here report the first case of IPAS arising a couple years after splenectomy with the appearance of an endocrine tumor of the pancreas.

PRESENTATION OF CASE

A 62-year-old female presented with a one-week history of left upper quadrant discomfort. She had splenectomy for the treatment of hypersplenism caused by cirrhotic portal hypertension two years before this admission. Her physical examination was unremarkable and laboratory data was within the normal range. Both the ultrasonography and magnetic resonance image revealed a small oval-shaped mass in the tail of her pancreas with the diameter 2 cm or less. A distal pancreatectomy was performed for the suspection of malignant neuroendocrine tumor of the pancreas. An intrapancreatic accessory spleen was confirmed by the pathologic examination.

DISCUSSION

Intrapancreatic accessory spleen is one kind of congenital ectopic spleen without indication for operative intervention. We present the case to support that intrapancreatic accessory spleen may enlarge through a compensatory mechanism, and raise the awareness of this intrapacreatic entity to avoid unnecessary surgical operation.

CONCLUSION

IPAS should be highly considered as a differential diagnosis while the lesion is no more than 2.5 cm in diameter and/or other accessory spleens show around the splenic hilum.