Cystic islet cell tumors: radiologic findings in three cases

Nondegenerated cystic neuroendocrine tumor of the pancreas: a case report

Background

Pancreatic neuroendocrine tumors (PNETs) are typically solid neoplasms but, in very rare cases, present as cystic lesions. We describe a case of a cystic neuroendocrine tumor that developed as a small cystic lesion.

Case presentation

In 2011, a 66-year-old Japanese woman underwent computed tomography (CT) that revealed a cystic lesion in the tail of the pancreas measuring 9 mm. She did not have any symptoms. She underwent a CT scan every year thereafter. The cystic lesion gradually increased and was 40 mm in 2019; endoscopic retrograde pancreatography (ERP) was then performed. Cytological examination demonstrated class IIIb adenocarcinoma, and we conducted laparoscopic distal pancreatectomy. Pathological examination showed PNET.

Conclusion

Although cystic change of PNET is generally caused by ischemia or necrosis inside the tumor, in our case, PNET occurred as a small cyst that increased without changing form.

The rare case of a cystic pancreatic neuroendocrine tumor

The pancreatic neuroendocrine tumors (PanNETs) most commonly present as solid neoplasms; however, very rarely, they may present primarily as cystic neoplasms. Most of the cystic PanNETs are non-secreting tumors, and the radiological features are not well defined. Hence pre-operative diagnosis is usually challenging and the tumors are misdiagnosed as mucinous cystic neoplasms, intraductal papillary mucinous neoplasms, serous cystic neoplasms, solid pseudopapillary neoplasms, and non-neoplastic cysts. However, the management depends on the accurate diagnosis of these cystic lesions, which poses a dilemma. Herein, we report the case of a cystic PanNET in the tail of the pancreas, which was clinically and radiologically misdiagnosed as a mucinous cystic neoplasm. This case is reported to highlight this issue to the medical community regarding the diagnostic difficulty in such rare non-functioning pancreatic neuroendocrine tumors.

Paraneoplastic pemphigus and myasthenia gravis as the first manifestations of a rare case of pancreatic follicular dendritic cell sarcoma: CT findings and review of literature

BACKGROUND

Follicular dendritic cell sarcoma (FDCS) is a rare neoplasm that originates from follicular dendritic cells in lymphoid tissue while paraneoplastic pemphigus (PNP) is an autoimmune blistering disease associated with neoplasms. Pancreatic FDCS associated with PNP and myasthenia gravis (MG) is even rarer and highly malignant. We present the clinical data, pathological materials and computed tomography (CT) features of a rare case of this disease.

CASE PRESENTATION

A 49-year-old woman presented with repeated ptosis of both eyelids, oral ulcers and erosions. Her laboratory results showed a slight elevation of CA125 and positivity of some autoimmune antibodies. CT revealed a round solid mass with central necrosis in the pancreatic tail. The solid component of the mass showed slight enhancement and serpentine feeding arteries in the arterial phase, moderate enhancement with a draining vein around the tumor in the portal venous phase and persistent enhancement in the delayed phase. Surgical resection was performed, and the pathological diagnosis was FDCS. However, the patient died of inability to excrete sputum and occlusion of the respiratory tract.

CONCLUSIONS

Pancreatic FDCS manifested as PNP and MG is very rare. Its CT features are not specific, and the disease should be differentiated from neuroendocrine tumors, solid pseudopapillary neoplasms and acinar cell carcinoma.

Clinicopathological characteristics of non-functioning cystic pancreatic neuroendocrine tumors

BACKGROUND/OBJECTIVES

The biological features of cystic pancreatic neuroendocrine tumors (PNETs) remain unclear. The aim of this study was to clarify the clinicopathological characteristics of non-functioning PNETs (NF-PNETs) with a cystic component.

METHODS

The medical records of 75 patients with NF-PNETs who had undergone resection in our institution were retrospectively reviewed. Clinicopathological factors were compared between PNETs with and without a cystic component. Expression of somatostatin 2 receptor (SSTR-2) was also analyzed.

RESULTS

Cystic PNETs were diagnosed in 14 patients (19%). The proportion of men was significantly higher for cystic than solid PNETs (79% vs. 44%, P < 0.05) and cystic PNETs were significantly larger than solid PNETs (25 mm vs. 17 mm, P < 0.01). However, there were no significant differences in the prevalence of lymph node metastases (14% vs. 10%, P = 0.64), hepatic metastasis (7% vs. 3%, P = 0.54), or disease-free survival rate (both 86%, P = 0.29) between PNETs with and without a cystic component. SSTR-2 expression was more frequently observed in PNETs with a cystic component than in those without (100% vs. 70%, P < 0.01).

CONCLUSIONS

Although cystic PNETs were larger upon diagnosis than solid PNETs in this study, prognosis after surgical resection did not differ significantly between these types of PNET. Somatostatin receptor scintigraphy and somatostatin analogues may be more useful for diagnosing and treating cystic PNETs, respectively.

Adult pancreatoblastoma: A case report and clinicopathological review of the literature

PURPOSE

Our purpose was to report a case of adult pancreatoblastoma, and review the literature in order to assist clinicians in the management of the disease.

MATERIALS AND METHODS

The demographic, clinical, and imaging findings of 41 patients with pathologically proven pancreatoblastoma from 1986 to 2017 identified in PubMed were reviewed. The key words used for searching PubMed were: "pancreatoblastoma", "pancreatic tumor", and "adult pancreatoblastoma." We also reported the details of a case of adult pancreatoblastoma treated at our institution.

RESULTS

We identified 41 cases of adult pancreatoblastomas, and the mean age at diagnosis was 41.4 ± 17.4 years. Pancreatoblastomas occurred in the pancreatic head in 48.4% of patients, and in 39.0% of cases the tumor was >8 cm in diameter at diagnosis. Patient age and tumor size were similar between males and females (P = 0.59; P = 0.32, respectively). Metastases was present in 17 of the 41 adult patients (41.5%). No significant difference in age, sex, tumor size, and tumor location was found between patients with and without metastases (P = 0.57, 0.58, 0.64, 0.39, respectively).

CONCLUSION

Preoperative diagnosis of adult pancreatoblastoma is difficult because of the heterogeneous, variable cellular differentiation and atypical clinical and imaging features. A pancreatoblastoma should be considered when tumors in the pancreas are solid and cystic.

Adult pancreatoblastoma - Case report and review of literature

Most cases of pancreatoblastoma, a rare malignant epithelial tumor of the pancreas, are seen in the pediatric population. The rarity of pancreatoblastoma, the similar radiologic findings to those seen in other pancreatic lesions, and its histopathologic heterogeneity, make its preoperative diagnosis in adults a real challenge. We report ultrasound, computed tomography and magnetic resonance imaging correlative findings of a histologically proven pancreatoblastoma in a 37-year-old woman. Pancreatoblastoma should be considered in the differential diagnosis of a pancreatic mass presenting uncommon imaging features.

A systematic review and meta-analysis of the clinicopathologic characteristics of cystic versus solid pancreatic neuroendocrine neoplasms

INTRODUCTION

Cystic pancreatic neuroendocrine neoplasms (PNENs) are rare neoplasms, and presently, it is uncertain whether their behavior is similar or distinct from their solid counterparts. This study aimed to review systematically the present literature to compare the clinicopathologic characteristics of cystic PNENs versus their solid counterparts to determine whether cystic PNENs are likely to be a distinct entity from solid PNENs.

METHODS

Comparative studies of solid versus cystic PNENs studies were reviewed. Cystic and solid PNENs were compared on the basis of several clinicopathologic characteristics.

RESULTS

Seven nonrandomized case control studies compared 152 cystic versus 915 solid PNENs. Pooled analysis demonstrated that the likelihood of PNENs to be located in the head/uncinate of the pancreas was lower for cystic than solid neoplasms (27.7% vs 45.5%, odds ratio [OR] 0.452, 95% confidence interval [95% CI] 0.304-0.673, P < .001). Cystic PNENs were less likely to be functional (14% vs 24.4%, OR 0.405, 95% CI 0.221-0.742, P = .003) and were more likely to be benign/uncertain rather than malignant compared with solid PNENs (90.3% vs 65.9%, OR 3.151, 95% CI 1.297-7.652, P = .011). Cystic PNENs were more likely to have a mitotic count <2 per 10 hpf and a Ki67 index <2% (93.3% vs 72.7%, OR 4.897, 95% CI 2.139-11.209, P < .001 and 82.4% vs 54.1%, OR 4.079, 95% CI 2.177-7.641, P < .001), respectively. Cystic neoplasms were also less likely to have regional lymph node metastases than solid neoplasms (11.2% vs 28.9%, OR 0.387, 95% CI 0.219-0.685, P = .001).In this meta-analysis, there was no difference in the 5-year overall survival and 5-year disease-free survival between cystic vs solid PNENs (92.0% vs 86.8%, P .214) and (98.1% vs 83.9%, P = .185).

CONCLUSION

These findings suggest that cystic PNENs tend to be biologically less aggressive compared with their solid counterparts; more data, however, with respect to molecular analysis are required to establish whether cystic and solid PNENs were distinct pathologic entities.

Imaging features of the less common pancreatic masses

Contrast-enhanced multiphase CT and dynamic gadolinium-enhanced MR have been validated in the literature as outstanding modalities for the evaluation of pancreatic pathology. In addition to the more frequently seen pancreatic adenocarcinoma, neuroendocrine tumors of the pancreas and cystic lesions such as serous and mucinous cystadenomas and IPMNs, a variety of benign and malignant lesions may occur in the pancreas. The purpose of this pictorial essay is to review the imaging findings of a variety of uncommon, benign and malignant, pancreatic neoplasms.

Pancreatic neuroendocrine tumor with cystlike changes: evaluation with MDCT

OBJECTIVE

The objective of our study was to determine the prevalence and CT appearance of cystlike changes of pancreatic neuroendocrine tumor (NET), particularly of small (≤ 3 cm) tumors.

MATERIALS AND METHODS

The clinical records, images, and pathologic reports of 74 consecutive patients (average age, 55.5 years) with surgically resected pancreatic NETs who underwent preoperative CT were retrospectively reviewed. The size and location of the pancreatic NETs were recorded. The tumors were classified on the basis of CT appearance as small (≤ 3 cm) or large (> 3 cm) and as solid, partially (≤ 50% or > 50%) cystic, or purely (≈ 100%) cystic. Peripheral contrast enhancement on CT was characterized, and lymph node and liver metastases found by pathologic examination were recorded.

RESULTS

A total of 78 pancreatic NETs were reviewed. Five were not visualized on CT, leaving 73 pancreatic NETs in 69 patients (multiple tumors were visualized on CT of three patients) for analysis. The mean size of the 73 tumors was 3.0 ± 2.6 (SD) cm (range, 0.7-13.1 cm); 52 tumors were 3 cm or smaller and 21 tumors were larger than 3 cm. Gross pathologic results confirmed that 13 of the 73 (17.8%) tumors were predominantly (> 50% or ≈ 100%) cystic: 10 of the 52 (19.2%) tumors 3 cm or smaller and three of the 21 (14.3%) tumors larger than 3 cm. Peripheral contrast enhancement was seen in 11 of the 13 (85%) predominantly cystic pancreatic NETs. Compared with solid pancreatic NETs, predominantly cystic pancreatic NETs were less commonly associated with lymph node and liver metastases.

CONCLUSION

Cystic pancreatic NETs are not rare and should be included in the differential diagnosis of a cystic pancreatic mass, particularly if the cystic mass is associated with peripheral contrast enhancement. A minority of cystic pancreatic NETs can present with no peripheral enhancement.

Cystic pancreatic neuroendocrine tumors: a clinicopathologic study

Pancreatic neuroendocrine tumors (PanNETs) are typically solid neoplasms but in rare instances may present as cystic lesions. This unusual presentation can make clinical diagnosis challenging. In addition, the clinical and histopathologic characteristics of cystic PanNETs are poorly defined. We identified 53 cystic PanNETs in our single-institution experience of 491 surgically resected PanNETs. Similar to solid PanNETs, cystic PanNETs developed with an equal sex distribution and over a wide age range (23 to 91 y; mean, 52 y). The unusual cystic appearance made radiologic differentiation from other cystic pancreatic neoplasms difficult with a misdiagnosis in 23 of 53 (43%) cases. An association between cystic PanNETs and multiple endocrine neoplasia type 1 or multifocal disease [5 of 53 (9%) and 7 of 53 (13%), respectively] was not observed as compared with solid PanNETs (P=0.34 and P=0.31, respectively). Grossly, cystic PanNETs were predominantly located in the tail of the pancreas (n=28, 53%) and were similar in size (mean, 3.3 cm) to solid PanNETs (mean, 4.1 cm; P=0.12). All cysts were unilocular (n=53, 100%) and filled with clear to straw-colored fluid. Larger cysts were sometimes noted to be hemorrhagic. Histologically, the cysts were lined by a thin fibrous band that separated the cyst from the neoplastic cells. In comparison with their solid counterparts, cystic PanNETs were less likely to demonstrate tumor necrosis (6%; P=0.04), perineural invasion (8%; P<0.001), vascular invasion (4%; P<0.001), regional lymph node metastasis (13%; P<0.001), and synchronous distant metastasis (4%; P=0.015). The neoplastic cells of the cystic PanNETs were well differentiated (n=53, 100%) with a low mitotic rate and low Ki-67 proliferation index (range, 0.2% to 11%; mean, 1.8%). On the basis of both the American Joint Cancer Committee and European Neuroendocrine Tumor Society staging systems, the majority of cystic PanNETs presented at a lower pathologic stage as compared with solid PanNETs. In summary, cystic PanNETs are a distinctive subgroup of PanNETs with unique clinical, radiographic, and pathologic features.

Cystic pancreatic neuroendocrine neoplasms with uncertain malignant potential: report of two cases

Neuroendocrine tumors of the pancreas (NETP) represent only 1%-2% of all pancreatic neoplasms. They can be classified as functioning or non-functioning, respectively, according to the presence or absence of paraneoplastic syndrome. Case 1 concerned a 70-year-old woman with a cystic lesion of the pancreatic head and body. All tumor markers were negative. The patient underwent a distal pancreatectomy. The histology revealed a well-differentiated endocrine tumor with uncertain malignant potential. Case 2 was a 61-year-old man with chronic polyserositis. The serum tumor markers were negative, while he was strongly positive for intracystic tumor markers carcinoembryonic antigen, carbohydrate antigen (CA) 19-9, and CA 125. The patient underwent a cephalo-pancreatic duodenectomy. The preoperative differential diagnosis of cystic NETP is still a challenge due to the high rate of the nonfunctional variant. Although cystic NETPs are well differentiated, they are still tumors with a malignant potential, and therefore an early diagnosis and radical surgical resection could be associated with a better long-term survival.

Clinico-pathological features of cystic pancreatic endocrine neoplasms and a comparison with their solid counterparts

AIM

Pancreatic endocrine neoplasms (PENs) may occasionally manifest as cystic lesions of the pancreas. The aim of this study is to report our experience with cystic PENs and to compare their clinico-pathological features with their solid counterparts.

MATERIALS AND METHODS

From 1990 to 2004, 38 patients with PENs were reviewed. Six of these tumours appeared on radiological imaging as a cystic lesion of the pancreas.

RESULTS

Of the 38 patients with a PEN, 21 of the patients were female and with a median age of 54.5 (range, 33-83) years. Sixteen patients had functional endocrine tumours of which insulinoma was the most common. The six patients with cystic PEN had a median age of 55.5 (range, 41-70) years and half were female. Cystic PENs were significantly larger [48 (range, 25-170) mm vs 19 (range, 3-120) mm, P = 0.013] and were less likely to be benign (0 vs 50%, P = 0.017) compared to their solid counterparts. There was no difference between cystic and solid PENs in terms of age, sex, presence of symptoms, proportion of functioning tumours and location of tumours within the pancreas.

CONCLUSION

Cystic PENs share many clinico-pathological features with solid PENs. These differ only in the cystic appearance and tend to be of a larger size. Hence, these findings suggest that cystic and solid PENs are unlikely to be distinct pathological entities but are likely to be morphological variants of the same entity.

Diagnostic imaging of cystic pancreatic neoplasms

Cystic pancreatic neoplasms are being diagnosed with growing frequency due to improving imaging technologies and increasing clinician awareness. Distinguishing cystic neoplasms from pseudocysts and discriminating among the various cystic neoplasms is essential to appropriate management. The backbone of diagnosis of these tumors continues to be cross-sectional imaging by CT and MRI. Despite refinements in technology and significant progress in characterizing these lesions, the overall accuracy of CT and MR is limited. EUS, especially as means of FNA, will have an increasing role in the evaluation of selected cases as experience grows. No radiologic investigation can reliably distinguish cystic neoplasms from pseudocysts nor differentiate among cystic neoplasms in all cases. For uncertain lesions, surgeons should favor either careful observation with serial imaging or surgical resection.

MR imaging features of solid pseudopapillary tumor of the pancreas in adult and pediatric patients

OBJECTIVE

This study was conducted to describe the MR imaging features of solid pseudopapillary tumor of the pancreas.

CONCLUSION

Solid pseudopapillary tumor of the pancreas, a tumor typically seen in young women, is a large, well-defined, encapsulated lesion with heterogeneous high or low signal intensity on T1-weighted, heterogeneous high signal intensity on T2-weighted, and early peripheral heterogeneous enhancement with progressive fill-in on gadolinium-enhanced dynamic MR imaging. These features help differentiate this rare tumor from other pancreatic neoplasms.

Imaging of cystic diseases of the pancreas

Although the majority of cystic lesions of the pancreas seen in clinical practice represent postinflammatory pseudocysts, it is important for the radiologist to be knowledgeable of the wide spectrum of cystic masses of the pancreas and the variable prognoses they possess. As a result of similarities in the imaging features of these lesions, a definitive diagnosis is often not possible. By combining imaging features with clinical history, a reasonable differential diagnosis can be offered to the referring physician. In some cases, biopsy or fluid aspiration may be required prior to surgery. In a patient without the appropriate history of pancreatitis and the presence of a cystic pancreatic mass, it is incumbent upon the radiologist to offer alternative diagnoses of cystic neoplasms of the pancreas.

Imaging and localization of pancreatic insulinomas

For pancreatic insulinomas, the treatment of choice is surgical excision, which when successful is curative. Intraoperative palpation combined with ultrasonography theoretically depict almost all tumors, however the accuracy of palpation is improved by the preoperative localization. All recent advances in imaging have improved the likelihood for curative surgical resection. Our purpose is to demonstrate the characteristics of all modalities, which may be used in the preoperative localization algorithm.

Cystic endocrine tumors of the pancreas: clinical, radiologic, and histopathologic features in 13 cases

Cystic endocrine tumors of the pancreas are rare and raise difficult clinical problems. Our aims were to reevaluate the diagnostic and therapeutic strategy and to assess their histopathologic characteristics. Thirteen cystic endocrine tumors diagnosed in 10 patients were included. Clinical, radiologic, and pathologic data were reviewed. There were 6 male and 4 female patients (median age, 46 yrs). Six patients had evidence of multiple endocrine neoplasia type 1 (MEN1) disease. Four had a functional endocrine syndrome. Ten tumors were visible on imaging studies. The most suggestive radiologic features were the existence of a peripheral hypervascular rim (10 cases) and images of cyst into cyst (two cases). On gross and histologic examinations, two distinct types were present. Macrocystic tumors (six cases) were unilocular and limited by a thick wall containing nests of tumor cells. Microcystic tumors (seven cases) were characterized by the presence of multiple cystic spaces directly lined by tumor cells. Surgical resection was performed in all cases. Three patients had lymph node metastases at the time of diagnosis. One patient is dead with metastatic dissemination. The others are alive without recurrence or metastasis. The diagnosis of endocrine tumor must be considered for any pancreatic cyst discovered in a patient with a history of MEN1 syndrome or with clinical features suggestive of this syndrome. Cystic pancreatic endocrine tumors must be treated by surgical resection because of their possible malignant evolution.

Nonfunctioning endocrine tumor of the pancreas with extrapancreatic growth and cyst formation: report of a case

We report a case of nonfunctioning endocrine tumor of the pancreas with extrapancreatic growth and cyst formation. A 48-year-old woman was admitted to our hospital with an upper abdominal mass, which was detected during a routine medical checkup. The preoperative diagnosis was a solid cystic tumor of the pancreas. The tumor, which measured about 7cm in diameter, arose from the head of the pancreas and had a thin stalk, measuring about 1 cm in diameter. The histopathological diagnosis was a malignant nonfunctioning endocrine tumor of the pancreas. Cyst formation occurred in 67% of the reported cases with extrapancreatic growth in Japan. It is speculated that the cyst formation in this disease is related to the large size of the tumor and to the extrapancreatic growth.