Fine-needle aspiration of intrapancreatic accessory spleen: Cytomorphologic features and differential diagnosis

The World Health Organization Reporting System for Pancreaticobiliary Cytopathology: Overview and Summary

The recently published WHO Reporting System for Pancreaticobiliary Cytopathology (World Health Organization [WHO] System) is an international approach to the standardized reporting of pancreaticobiliary cytopathology, updating the Papanicolaou Society of Cytopathology System for Reporting Pancreaticobiliary Cytology (PSC System). Significant changes were made to the categorization of benign neoplasms, intraductal neoplasms, mucinous cystic neoplasms, and malignant neoplasms considered low grade. Benign neoplasms, such as serous cystadenoma, categorized as Neoplastic: benign in the PSC system, are categorized as Benign/negative for malignancy in the WHO system. Pancreatic neuroendocrine tumor, solid-pseudopapillary neoplasm, and gastrointestinal stromal tumor, categorized as Neoplastic: other in the PSC system, are categorized as Malignant in the WHO System in accord with their classification in the 5th edition WHO Classification of Digestive System Tumours (2019). The two new categories of Pancreaticobiliary Neoplasm Low-risk/grade and Pancreaticobiliary Neoplasm High-risk/grade are mostly limited to intraductal neoplasms and mucinous cystic neoplasms. Low-risk/grade lesions are mucinous cysts, with or without low-grade epithelial atypia. High-risk/grade lesions contain neoplastic epithelium with high-grade epithelial atypia. Correlation with clinical, imaging, and ancillary studies remains a key tenet. The sections for each entity are written to highlight key cytopathological features and cytopathological differential diagnoses with the pathologist working in low resource setting in mind. Each section also includes the most pertinent ancillary studies useful for the differential diagnosis. Sample reports are provided for each category. Finally, the book provides a separate section with risk of malignancy and management recommendations for each category to facilitate decision-making for clinicians.

Intrapancreatic accessory spleen with an epidermoid cyst: a malignant mimicry

With the liberal use of CT scan for clinical diagnosis, clinicians are faced with an increasing number of pancreatic incidentalomas. Compared with other incidentalomas, pancreatic incidentalomas have higher chances of future malignant transformation. There are many differential diagnoses, and epidermoid cyst in an intrapancreatic accessory spleen (ECIPAS) is extremely rare, with only a handful of reports. Preoperative diagnosis is often complicated, and the final diagnosis is usually only made after surgical resection.We report a 34-year-old man who had an incidentally noted 2.8 cm pancreatic tail cystic lesion on a CT scan done for urinary symptoms. The lesion had a solid nodular component that was worrisome for malignancy, and the patient underwent further evaluation with an MRI scan and endoscopic ultrasound of the pancreas. The differential diagnoses of cystic degeneration of neuroendocrine tumour, branch-duct intraductal papillary mucinous neoplasm with worrisome features or ectopic intrapancreatic spleen were made. A multidisciplinary tumour board recommended surgical resection given risk features of malignancy. The patient subsequently underwent a laparoscopic distal pancreatectomy with splenectomy, and histology confirmed the diagnosis of ECIPAS.Imaging characteristics of ECIPAS are non-specific, and most patients have a diagnosis made only after surgery. Therefore, more evidence is warranted for accurate preoperative imaging diagnosis to avoid unnecessary pancreatic surgery, which is not without its risks.

Inflammatory and tumor-like lesions of the pancreas

Inflammatory/tumor-like lesions of the pancreas represent a heterogeneous group of diseases that can variably involve the pancreatic gland determining different signs and symptoms. In the category of inflammatory/tumor-like lesions of the pancreas, the most important entities are represented by chronic pancreatitis, which includes alcoholic, obstructive and hereditary pancreatitis, paraduodenal (groove) pancreatitis, autoimmune pancreatitis, lymphoepithelial cyst, pancreatic hamartoma and intrapancreatic accessory spleen. An in-depth knowledge of such diseases is essential, since they can cause severe morbidity and may represent a potential life-threatening risk for patients. Furthermore, in some cases the differential diagnosis with malignant tumors may be challenging. Herein we provide a general overview of all these categories, with the specific aim of highlighting their most important clinic-pathological hallmarks to be used in routine diagnostic activities and clinical practice.

WFUMB Position Paper-Incidental Findings, How to Manage: Spleen

The World Federation for Ultrasound in Medicine and Biology (WFUMB) is addressing the issue of incidental findings (IFs) with a series of publications entitled "Incidental Imaging Findings-The Role of Medical Ultrasound." IFs are less commonly encountered in the spleen than in many other abdominal organs but remain a frequent dilemma in clinical practice. A histological diagnosis is rarely necessary for patient management. Many IFs, such as secondary spleens and splenic cysts, are harmless and do not require any further investigation. The diagnosis of many other focal splenic lesions is, however, often problematic. The following overview is intended to illustrate a variety of incidentally detected spleen pathologies such as size variants, shape variants, secondary spleens, focal splenic lesions and splenic calcifications. It should aid the examiner in establishing the diagnosis. Moreover, it should help the ultrasound practitioner decide which pathologies need no further investigation, those requiring interval imaging and cases in which immediate further diagnostic procedures are required.

Laparoscopic spleen-preserving distal pancreatectomy for epidermoid cyst in an intrapancreatic accessory spleen: A case report

RATIONALE

Pancreatic tail cystic lesions are increasingly encountered in clinical practice, however, it is difficult to make a correct diagnosis preoperatively because there are many types of pancreatic neoplastic and non-neoplastic cysts. Epidermoid cyst in an intrapancreatic accessory spleen (ECIPAS) is a rare non-neoplastic cyst locating in the pancreatic tail, and it is commonly misdiagnosed as another cystic neoplasm.

PATIENT CONCERNS

A 51-year-old man was admitted for investigation of abdominal pain. The physical examination and laboratory tests found no abnormalities, except for an elevation of carbohydrate antigen (CA)19-9. Imaging revealed a cystic lesion within the pancreatic tail, and the solid component surrounding the cyst was enhanced similarly to those of the splenic tissue.

DIAGNOSIS

ECIPAS was diagnosed based on the pathology after surgery. The mass was composed of a cyst and brown solid spleen-like tissue. The microscopic analysis demonstrated that the solid component was accessory splenic tissue, and the cyst wall was lined with a thin stratified squamous epithelium.

INTERVENTIONS

Laparoscopic spleen-preserving distal pancreatectomy was performed.

OUTCOMES

The patient was discharged on day 5 postoperatively after an uneventful recovery. CA19-9 returned to normal after surgery. During a 2-years follow-up, there was no evidence of tumor recurrence.

LESSONS

Although rare ECIPAS should be considered in the differential diagnosis of pancreatic tail cystic lesions, and the typical imaging features might facilitate the preoperative diagnosis. Laparoscopic distal pancreatectomy is a safe and effective approach for treating ECIPAS.

Epidermoid cyst in an intrapancreatic accessory spleen in the pancreas head: a case report

Background

An epidermoid cyst in an intrapancreatic accessory spleen (ECIPAS) in the pancreas head is an extremely rare condition. The natural course of this condition is not well known, and it is difficult to diagnose before surgery due to the lack of specific imaging findings.

Case presentation

A tumor was found in the head of the pancreas in a 68-year-old man with abdominal distension and discomfort. Magnetic resonance imaging (MRI) suggested a malignant tumor, such as a colloid cancer. The tumor was removed surgically, with pathologic examination showing that it was an ECIPAS.

Conclusion

ECIPAS cannot be easily distinguished from other pancreatic cystic tumors, making it necessary to include ECIPAS in the differential diagnosis of these tumors. Unnecessary surgical resection may be avoided by more accurate preoperative diagnosis based on clinical and imaging characteristics.

Epithelial cyst arising in an intrapancreatic accessory spleen: a case report of robotic surgery and review of minimally invasive treatment

Background

An epithelial cyst in an intrapancreatic accessory spleen (ECIPAS) is rare. We report a case of ECIPAS that was treated with robot-assisted distal pancreatectomy with splenectomy.

Case presentation

The case was a 59-year-old woman who was referred to our hospital after a pancreatic tail tumor was found on computed tomography prior to surgery for small bowel obstruction at another hospital. A cystic lesion in the pancreatic tail was discovered and evaluated by magnetic resonance imaging and endoscopic ultrasonography. Based on clinical and radiological features, mucinous cystic neoplasm was included in the differential diagnosis. The patient underwent robot-assisted distal pancreatectomy with splenectomy. The postoperative course was uneventful. Pathological evaluation revealed a 20-mm ECIPAS in the pancreatic tail.

Conclusions

If a pancreatic tail tumor is present, ECIPAS should be included in the differential diagnosis. However, preoperative diagnosis is difficult, and a definitive diagnosis is often not obtained until after surgery. Surgery should be minimally invasive. Laparoscopic distal pancreatectomy has become a standard surgical procedure because it is minimally invasive. Robot-assisted surgery is not only minimally invasive, but also advantageous, because it has a stereoscopic magnifying effect and allows the forceps to move smoothly. Robot-assisted distal pancreatectomy may be a good option, when performing surgery for a pancreatic tail tumor.

Intrapancreatic Accessory Spleen Masquerading as a Pancreatic Mucinous Neoplasm

Incidentally discovered pancreatic cysts have become more common with increasing use of abdominal cross-sectional imaging. Tools that help us to better risk stratify a pancreatic cyst include advanced imaging techniques, such as pancreatic protocol computed tomography (CT) scan or magnetic resonance imaging (MRI) with cholangiopancreatography. Endoscopic ultrasound (EUS) and fine-needle aspiration (FNA) are invasive measures to better define and sample cysts especially if high-risk features are present. EUS may also yield pancreatic cyst fluid for analysis of carcinoembryonic antigen (CEA) which is elevated in mucinous cysts. This case highlights a rare finding of a mucinous, epidermoid cyst in an intrapancreatic accessory spleen (IPAS) with high-risk features on EUS.

Gamna-Gandy bodies in fine-needle aspiration from abdominal splenosis: A clue to underlying portal hypertension

A 40-year-old woman presented with abdominal pain and jaundice. Past medical history was significant only for splenectomy following a motor vehicle accident. Owing to presence of multiple peritoneal nodules on computerized tomography (CT) and elevated serum CA-125, ovarian peritoneal carcinomatosis was suspected. Ultrasound-guided fine-needle aspiration (FNA) revealed presence of abundant hemosiderin, leukocytes, endothelial cells, and fungal hypha-like structures. No evidence of neoplasia was found. Findings were consistent with Gamna-Gandy bodies (GGBS) within splenic tissue. Based on history of splenectomy and FNA findings, a diagnosis of abdominal splenosis with presence of GGBS was made. Workup for hepatic cirrhosis and portal hypertension was recommended. Liver biopsy confirmed presence of cirrhosis. To our knowledge, this is the first report of GGBS identified within abdominal splenosis. It is important for pathologists to be able to recognize GGBS and to be aware of their relationship to portal hypertension and other conditions associated with severe vascular congestion or hemorrhage. History and pathogenesis of GGBS, their diagnostic morphologic features and a review of cases of GGBS diagnosed via cytology are given.

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.

Accessory spleen located in the right parietal peritoneum: The first case report

RATIONALE

Accessory spleen is a congenital abnormality caused by failure of the splenic anlage to fuse during embryology. The presence of an accessory spleen located in the parietal peritoneum has not been reported so far, and an accessory spleen situated on the right side is extremely rare. In the present study, we describe the first case of an accessory spleen located in the right parietal peritoneum.

PATIENTS CONCERNS

A 65-year-old man, presented with pain in his left abdomen for 1 month.

DIAGNOSES

With ultrasonography and computed tomography, it was difficult to determine the accurate location and diagnosis, and an abdominal fibroma was preoperatively considered.

INTERVENTIONS

By laparotomy, we found a mass connected to the right parietal peritoneum by a vascular pedicle. We resected it completely, and the gross specimen measured 5.0 × 3.0 × 2.5 cm and was a localized tumor with a capsule.

OUTCOMES

Microscopically, sinusoids were visible, as well as scattered lymphoid follicles, eosinophils, histiocytes, plasma cells, neutrophils, and red blood cells, indicative of splenic tissue. Finally, the lesion was diagnosed as an accessory spleen located in the right parietal peritoneum. Postoperatively, he recovered well and was followed up for a 31 months, during which he was well with no complication.

LESSONS

We present the first accessory spleen located in the right parietal peritoneum. Awareness of the accessory spleen and familiarity with typical imaging findings are necessary for surgeons to make a precise preoperative diagnosis.

Epidermoid Cyst in an Intrapancreatic Accessory Spleen: Case Report and Literature Review of the Preoperative Imaging Findings

An epidermoid cyst arising within an intrapancreatic accessory spleen (ECIAS) is rare, and also difficult to correctly diagnose before surgery. It is mostly misdiagnosed as a cystic tumor, such as a mucinous cystic neoplasm or as a solid tumor with cystic degeneration, such as a neuro endocrine tumor. We herein report a case of ECIAS and also perform a literature review of 35 reports of ECIAS. Although the preoperative diagnosis of ECIAS using conventional imaging is relatively difficult to make, careful preoperative examinations of the features on computed tomography and magnetic resonance imaging could lead to a correct preoperative diagnosis of ECIAS which might thereby reduce the number of unnecessary resections.

A rapidly growing epidermoid cyst in an intrapancreatic accessory spleen treated by laparoscopic spleen-preserving distal pancreatectomy: Report of a case

Epidermoid cysts arising in an intrapancreatic accessory spleen are exceedingly rare, furthermore the natural course of them is hardly known. We report a case correctly diagnosed with epidermoid cyst in an intrapancreatic accessory spleen, followed by 1 year observation, finally underwent surgical treatment. The patient presented with diarrhea. Contrast-enhanced computed tomography (CT) revealed a pancreatic cyst 20 mm in diameter, surrounded by a solid component showing the same enhancement as the spleen, suggesting the presence of an epidermoid cyst in an intrapancreatic accessory spleen. One year later, back discomfort developed, and a CT scan revealed that the cyst had grown to 38 mm in diameter. To obtain a definitive diagnosis, we performed a laparoscopic spleen-preserving distal pancreatectomy. The histopathological diagnosis was compatible with an epidermoid cyst in an intrapancreatic accessory spleen, which is benign. The postoperative course was uneventful. This case demonstrates that an epidermoid cyst arising in an intrapancreatic accessory spleen can rapidly grow, even if it is benign. Laparoscopic spleen-preserving distal pancreatectomy can be a useful procedure, with the advantages of low invasiveness and organ preservation, for the treatment of benign or low-grade malignant tumors located in the pancreatic body or tail.

Endoscopic ultrasound-guided pancreatic fine-needle aspiration: potential pitfalls in one institution's experience of 1212 procedures

BACKGROUND

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has emerged as the diagnostic modality of choice for mass lesions in the pancreas. The objective of the current study was to determine the accuracy and pitfalls of EUS-FNA in the diagnosis of pancreatic lesions in cases that involved follow-up surgical resection.

METHODS

Cases of EUS-FNA of pancreatic lesions performed from 2007 to mid-2012 for which subsequent surgical resection was performed were retrieved from the department's database. The accuracy of the cytologic diagnosis was assessed using the histological diagnosis as the gold standard. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated. "Neoplastic," "suspicious," and "malignant" were classified as a positive cytologic diagnosis. In one calculation method, "atypical" was also included as a positive cytologic diagnosis whereas in another it was not considered to be a positive cytological result. The cases with a cytologic-histological discrepancy were reviewed to identify sources of errors.

RESULTS

A total of 1212 cases from 1104 patients (518 women and 586 men; age range, 18-94 years [average age, 63.5 years]) were identified. Cytologic diagnoses included 52 unsatisfactory, 224 benign, 129 atypical, 140 neoplasm, 35 suspicious, and 632 malignant diagnoses. Of these cases, 397 patients had histological follow-up information available. The sensitivity, specificity, positive predictive value, and negative predictive value were 83.2%, 85.9%, 95.9%, and 56.1%, respectively, with atypical cases excluded from the analysis. When atypical cases were included as a positive cytologic diagnosis, the sensitivity, specificity, positive predictive value, and negative predictive value were 86.7%, 67.9%, 90.7%, and 58.5%, respectively, and were 73.7%, 87.7%, 95.6%, and 48.0%, respectively, when atypical cases were included as a negative cytologic diagnosis. The major difficulty in EUS-FNA cytology was to differentiate pancreatic mucinous neoplasms from contaminants of gastric mucosa. Other pitfalls included differentiating mucinous neoplasm from extensive pancreatic intraepithelial neoplasia, and endocrine tumor from nesidioblastosis versus acinar cell carcinoma or intrapancreatic spleen.

CONCLUSIONS

EUS-FNA is a valuable tool for the diagnosis of pancreatic lesions, especially solid malignant tumors. Cytologic-radiological correlation is essential in differentiating pancreatic mucinous neoplasms from gastric mucosa, because the former usually are found to have characteristic features on imaging. Pathologists should be aware of the pitfalls in the cytologic diagnosis of pancreatic lesions that may significantly change the clinical management of the patients.

Pitfalls in EUS FNA

Although endoscopic ultrasound (EUS) fine-needle aspiration (FNA) is a safe and accurate procedure, the diagnostic yield varies. Factors contributing to the diagnostic accuracy of EUS FNA include endosonographer and cytopathologist experience, EUS image recognition, accurate FNA targeting of the lesion, proper specimen collection and handling, use of ancillary techniques, and accurate cytologic interpretation. Errors in performance or judgment made before, during, or after the procedure may affect the results of the EUS FNA. The authors discuss the potential pitfalls of EUS FNA and methods to avoid their occurrence to optimize the diagnostic yield, efficiency, and safety of the procedure.