Macrocystic serous cystadenoma of the pancreas

Differentiating benign from malignant pancreatic cysts on computed tomography

•

CT can distinguish between benign and premalignant or malignant pancreatic cysts.

•

Solid component and septation were the only CT features that could differentiate benign from malignant cysts.

•

Cyst wall enhancements on CT were more commonly observed in premalignant or malignant cysts than in benign cysts.

•

CT is a necessary diagnostic modality to preoperatively detect and characterize pancreatic lesions.

Purpose

It is important to identify features on computed tomography (CT) that can distinguish between benign and premalignant or malignant pancreatic cysts to avoid unnecessary surgeries. This study investigated the preoperative diagnostic evaluation of cystic pancreatic lesions to determine how advanced imaging and clinical factors should guide management.

Methods

In total, 53 patients with 27 benign and 26 premalignant or malignant cysts were enrolled. CT features of the cysts were compared using univariate and multivariate analyses.

Results

On univariate analysis, a solid component (p < 0.01), septation (p < 0.01), location (p < 0.01), border (p < 0.01), wall enhancement (p = 0.01), lesion margins (p < 0.01), pancreatic atrophy (p = 0.04), and a cystic wall (p < 0.01) were all significantly different between benign and premalignant or malignant cysts. On multivariate analysis, only a solid component (p < 0.01) and septation (p < 0.01) were significant.

Conclusion

A thin cystic wall, uniform homogeneity, a clear border, the presence of septation, pancreatic atrophy, and the absence of both wall enhancements and solid components were more frequently seen in benign cysts. A thick wall, lack of homogeneity, the presence of wall enhancements and solid components, absence of septation, only a small degree of pancreatic atrophy, and unclear borders were more frequent among premalignant or malignant cysts. The only CT features to differentiate benign from premalignant or malignant cysts were a solid component and septation.

Lymphangioma of the pancreas: a multimodal approach to pre-operative diagnosis

BACKGROUND

Lymphangioma of the pancreas is an extremely rare benign tumour of lymphatic origin, with only four cases diagnosed by EUS-FNA reported to date.

METHODS AND MATERIALS

Five cases of either cytologically or histologically diagnosed pancreatic lymphangioma with pre-operative cytological analysis by EUS-FNAC were reviewed.

RESULTS

All patients were female, with a mean age of 56.4 years. By imaging, the cystic lesions ranged in size from 2 to 7 cm (mean 4.5 cm) and were mainly located in the head of the pancreas. All cysts had thin walls and no cyst demonstrated a mural nodule. Diagnosis based on imaging features was benign in all cases due to the absence of high-risk features. Four samples were sent for biochemical analysis, which showed low CEA levels (range, <0.5-19.4 ng/ml; mean, 5.45 ng/ml) and CA 19.9 and CA 72.4 levels within normal range. All cyst fluids showed numerous small lymphocytes with no atypia; no epithelial cells were present, including no gastrointestinal contamination. Flow cytometry in two cases showed T lymphocytes with a mature phenotype. Surgical resection in two patients confirmed the cytological diagnosis. Benign clinical follow-up was available in three patients at 2, 3 and 3.5 years.

CONCLUSION

A multimodal approach to cytological diagnosis (combining clinical, radiological and cyst fluid gross, biochemical and cytological characteristics) can lead to the diagnosis of this cystic neoplasm and distinguish it from other more common cysts in the pancreas, potentially avoiding the need for unnecessary surgery.

Comparative immunohistochemical study of the stroma of serous and mucinous cystic neoplasms: possible histopathogenetic relationship of the 2 entities

OBJECTIVES

Serous and mucinous cystic neoplasms (SCNs/MCNs) are the most common true cystic neoplasms of the pancreas and occur more frequently in women. The aim of this study was to characterize the stroma of SCNs to compare its phenotype with that of MCNs.

METHODS

A total of 12 SCNs and 5 MCNs were analyzed immunohistochemically using the following antisera: progesterone receptor (PR), estrogen receptor (ER), inhibin, CD10, and vimentin. Normal pancreatic tissue (17 cases) and ductal adenocarcinomas of the pancreas (3 cases) were used as controls.

RESULTS

Eight of 12 patients with SCNs and all 5 patients with MCNs were women. For SCNs, the stroma was sclerotic and paucicellular and showed focal moderate to strong reactivity for PR. Estrogen receptor, CD10, and inhibin were virtually negative. For MCNs, the stroma was more cellular and ovarianlike and showed a larger number of PR-positive cells with focal expression of ER and inhibin. Vimentin was expressed in all stromal cells in both groups.

CONCLUSIONS

Both SCNs and MCNs contain PR-positive stromal cells. In view of the aforementioned clinical and immunophenotypical similarities, we suggest that in SCNs and MCNs, the stromal framework is similar in origin and/or differentiation.

Three cases of serous oligocystic adenomas of the pancreas; evaluation of cyst wall thickness for preoperative differentiation from mucinous cystic neoplasms

BACKGROUND

Serous oligocystic adenoma (SOA), a rare pancreatic neoplasm, is generally a benign lesion without the necessity of surgery. Preoperatively, it is difficult to discriminate SOA from mucinous cystic neoplasm (MCN), which essentially needs surgical treatment. The purpose of this study was to evaluate the cyst wall thickness of SOAs and MCNs for preoperative differential diagnosis.

METHODS

We experienced three cases of SOAs with typical histopathological features. The cyst wall thickness of the SOAs was evaluated in the area protruding out of the pancreas and was compared with that of 13 MCNs histopathologically. The same evaluation and comparison were conducted on preoperative computed tomography (CT) images retrospectively.

RESULTS

The SOAs had a uniformly thin cyst wall measuring less than 1 mm. In contrast, the largest area of a cyst wall in MCNs ranged from 2.5 to 10.0 mm. On CT images, all but one of the MCNs showed a detectable cyst wall, while the cyst walls were hardly recognizable in two of the three SOAs.

CONCLUSIONS

For preoperative differentiation between SOAs and MCNs, the evaluation of cyst wall thickness may be an important tool and may contribute to the decision of treatment strategy.

Macrocystic pancreatic lesions: differentiation of benign from premalignant and malignant cysts by CT

OBJECTIVE

To assess useful CT features for differentiating benign from premalignant and malignant macrocystic pancreatic lesions.

METHODS

Seventy-four patients with pathologically proven macrocystic pancreatic lesions were enrolled: 17 benign cysts (macrocystic serous cystadenoma, n=12; congenital cyst; n=5) and 57 premalignant and malignant cysts (mucinous cystic neoplasm, n=28; intraductal papillary mucinous neoplasm of branch duct type, n=20; tumor with cystic change, n=9). Size, location, shape (lobulated, round or oval, or complex cystic with tubular cyst), wall thickness (thin, < or =1mm; thick, >1mm), internal surface (smooth or irregular), and other findings were analyzed with multiphasic CT with thin-section (2.5-3mm) images. CT features between two groups were compared using univariate and multivariate stepwise logistic regression analyses.

RESULTS

On univariate analysis, the differences for the shape (p=0.007), wall thickness (p=0.011), and internal surface (p=0.012) between benign and premalignant and malignant cysts were significant. A lobulated shape, a thin wall and a smooth internal surface were more frequent in benign cysts, whereas a round or oval shape or a complex cystic shape with tubular cyst, a thick wall and an irregular internal surface were more frequent in premalignant and malignant cysts. On multivariate analysis, the shape (p=0.002) and wall thickness (p=0.025) were significant CT features for differentiating benign from premalignant and malignant cysts.

CONCLUSION

Shape and wall thickness are the main CT features for differentiating benign from premalignant and malignant macrocystic pancreatic lesions.

Multiple synchronous serous cystadenomas of the pancreas: uncommon CT and MRI findings

Serous cystadenomas (SCAs) of the pancreas are benign cystic tumors. Although still controversial, asymptomatic SCAs, in contrast to their mucinous counterparts, can be treated conservatively. This attitude is mostly defendable for lesions of the pancreas head or multiple lesions distributed throughout the entire pancreas, as their surgical resection is still associated with significant morbidity. Thus, correct diagnosis is essential, and this relies on radiological and biological characteristics. Asymptomatic multiple SCAs are rare. Most cases described in the literature are either symptomatic, degenerated, or both. We present a case of huge (>10 cm), multiple asymptomatic SCAs, not associated with von Hippel-Lindau disease, involving the entire pancreas. The patient has been followed up for 3 years and remains asymptomatic. Tumor markers were within normal ranges. On abdominal computed tomography (CT) and magnetic resonance imaging (MRI), the lesions showed pathognomonic characteristics of SCAs, and their uncommon dimensions and number remained stable over time. 18-Fluorodeoxyglucose positron emission tomography (PET) scan performed at 3-year follow-up did not show hypermetabolic lesions.

Magnetic resonance imaging in the assessment of cystic pancreatic lesions: differentiation of benign and malignant lesion status

PURPOSE

To characterize cystic pancreatic lesions and tumors with magnetic resonance imaging (MRI), and to assess the value of morphological criteria in differentiating pseudocysts versus cystic tumors and benign versus malignant cystic tumors.

MATERIAL AND METHODS

Twenty-three patients with cystic pancreatic tumors or lesions underwent plain and contrast-material-enhanced MRI, including magnetic resonance cholangiopancreatography (MRCP). The MR findings were characterized and analyzed by two readers, and the role of various imaging criteria and combinations thereof for final lesion assignment were assessed. Final diagnoses were obtained from the results of open surgery (n = 19) and/or biopsy (n = 4).

RESULTS

Final diagnoses included cystic tumors (n = 11) and pseudocysts (n = 12). The lesions were located in the head (56%) and body or tail (44%). Lesion diameters ranged from 7 to 50 mm. Various lesion contrast enhancement patterns were observed for both benign and malignant lesions. Serous cystadenomas were located in the head, they were lobulated, and had wall diameters < or = 2 mm; with the combination of these characteristics all patients with serous cystadenoma could be identified, whereas in no other patient was this constellation observed.

CONCLUSION

MRI facilitated the diagnosis of serous cystadenomas, although no definite morphologic criterion for the differentiation between pseudocysts and mucinous cystadenomas was identified. In consideration of the substantial therapeutic consequences, either diagnostics in unclear cystic pancreatic lesions should comprise cyst fluid analysis if necessary, or eligible patients should be referred for surgical resection.

[Unilocular macrocystic serous cystoadenoma of the pancreas]

The differential diagnosis between macrocystic serous cystoadenoma and mucinous cystoadenoma is very difficult but is highly important due to the latter's potential for malignant transformation. We present a case of unilocular macrocystic serous cystoadenoma. Due to the impossibility of obtaining an accurate preoperative diagnosis, all macrocystic unilocular lesions, in an appropriate clinical context, must be resected.

Unusual imaging appearances of pancreatic serous cystadenoma: correlation with surgery and pathologic analysis

BACKGROUND

We describe imaging and pathologic features of serous cystadenoma of the pancreas on multislice helical computed tomography CT (MS-CT) and surgical resection.

METHODS

Radiologic and pathologic features were analyzed in five patients. All patients underwent MS-CT and digital subtraction angiography (DSA), and four patients underwent magnetic resonance (MR) imaging. Preoperatively, three cases showed radiologic evidence of mainly solid appearance on MS-CT, and the suspected diagnoses were solid pancreatic tumors (patients 1-3). The other two cases showed radiologic evidence of macrocystic tumor of the pancreas, and the suspected diagnoses were mucinous cystic tumors (cases 4 and 5). All patients underwent surgery, and the diagnosis of serous cystadenoma was confirmed on pathologic examination.

RESULTS

In three cases that showed a solid appearance on MS-CT, a microcystic appearance was identified on microscopic examination, and the tumors were found to be hypervascular lesions on multiphasic contrast-enhanced CT and DSA. In cases 1 and 2, the lesions showed high intensity with internal septation on T2-weighted MR images. In two cases, the tumors were classified as a macrocystic variant of serous cystadenoma, and no mural nodules, papillary projections, or calcifications were seen in the tumors.

CONCLUSION

Imaging appearance of serous cystadenoma on MS-CT is various and sometimes indistinguishable from that of solid tumor or mucinous cystic tumors of the pancreas. Imaging findings of hypervascularity and a well-marginated high-intensity lesion with internal septation on T2-weighted MR imaging may be crucial to identify serous cystadenoma that contains no visible cystic compartments on MS-CT.

Macrocystic pancreatic cystadenoma: The role of EUS and cyst fluid analysis in distinguishing mucinous and serous lesions

BACKGROUND

Benign pancreatic serous cystadenoma usually is morphologically distinguishable from mucinous cystadenomas, which require resection because of their malignant potential. A macrocystic variant of serous cystadenoma recently has been described, rendering this important distinction more difficult. The aim of this study was to determine the EUS and tumor marker characteristics of mucinous cystadenoma compared with macrocystic serous cystadenomas.

METHODS

Medical records for consecutive patients seen between 1995 and 2002, with a histopathologic diagnosis of mucinous cystadenoma or macrocystic serous cystadenoma after surgery, who had undergone a detailed EUS examination, including EUS-guided FNA, were retrospectively reviewed.

RESULTS

A resection specimen was available for 32 mucinous cystadenomas and 9 macrocystic serous cystadenomas. No significant differences were observed with regard to clinical data (age, gender, presence of symptoms), lesion size, and location within the pancreas. All mucinous cystadenomas had a discernible cyst wall (thickened, 66%; focal parietal nodules, 25%) compared with 56% of macrocystic serous cystadenomas (p<0.0001). A thick echo content also was more frequent in mucinous cystadenoma (56% vs. 11%; p=0.04; statistical significance removed by the Bonferroni correction). Microcysts were only observed in macrocystic serous cystadenomas (44%; p=0.0008). The combination of a cyst wall that is thickened and the absence of microcysts had a sensitivity of 100% and specificity of 78% for the diagnosis of mucinous cystadenoma compared with macrocystic serous cystadenoma. Although intracystic carbohydrate-associated antigen 72-4 and mucins M1 were non-discriminatory, low carcinoembryonic antigen (<5 ng/mL) and carbohydrate-associated antigen 19-9 (<50,000 U/mL) values were found in macrocystic serous lesions (respectively, 100% and 100%; p=0.0002 and p=0.0002).

CONCLUSIONS

Although there is considerable overlap, helpful EUS characteristics that differentiate mucinous cystadenoma from macrocystic serous cystadenoma include a thick cyst wall and microcysts. These features, coupled with analysis of aspirated fluid for tumor markers (especially carcinoembryonic antigen), should help to confirm the diagnosis.

Serous oligocystic adenoma of the pancreas

Cystic neoplasms of the pancreas are uncommon lesions but are becoming increasingly prevalent. Herein we report a case of an oligolocular cystic lesion in the head of the pancreas in a young female that had undergone a cystenteroanastomosis 10 years ago. She underwent a duodenopancreatectomy with an uneventful recovery. The histology showed a serous oligocystic adenoma of the pancreas and the immunohistochemistry study confirmed the diagnosis. There is no sign of recurrence after the surgery. The role of pre-operative diagnosis based on tomographic, echoendoscopy and fine needle aspiration are discussed.

Discrimination of unilocular macrocystic serous cystadenoma from pancreatic pseudocyst and mucinous cystadenoma with CT: initial observations

PURPOSE

To compare the computed tomographic (CT) appearance of pancreatic unilocular macrocystic serous cystadenoma, mucinous cystadenoma, and pseudocyst to determine if there are findings that assist in the differential diagnosis.

MATERIALS AND METHODS

CT findings in 33 patients (24 women, nine men; age range, 18-84 years; mean age, 41 years) with unilocular pancreatic lesions (macrocystic serous cystadenoma, n = 12; mucinous cystadenoma, n = 11; pseudocyst, n = 10) were retrospectively and jointly reviewed by two blinded observers. Twenty-three patients underwent helical CT, which included pancreatic and portal venous phase imaging with delays of 40 seconds and 65 seconds, respectively, after contrast material injection. Ten patients underwent conventional (nonhelical) CT. The number, size, location, and contour of lesions were reviewed, along with wall thickness and enhancement and other signs of pancreatic and peripancreatic involvement. Diagnosis was based on lesion resection (n = 22) or on a combination of cytologic findings, biochemical markers, and tumor markers (n = 11). The Fisher exact test was used to analyze the results.

RESULTS

Three of four CT findings were independently specific for macrocystic serous cystadenoma: location in the pancreatic head, lobulated contour, and absence of wall enhancement. When two of these four criteria were used in combination, 83% (10 of 12) of patients with unilocular macrocystic serous cystadenoma were identified. When three or four of these criteria were used, a specificity of 100% was achieved. Location in the pancreatic head (P <.05), lobulated contour (P <.005), and lack of wall enhancement (P <.005) were specific for macrocystic serous cystadenoma in comparison with mucinous cystic tumor. Lobulated contours (P <.005) were specific for macrocystic serous cystadenoma in comparison with pseudocyst. Other CT findings were not helpful in distinguishing between the three types of lesions.

CONCLUSION

A combination of CT findings is helpful in making the diagnosis of pancreatic unilocular macrocystic serous cystadenoma.

Macrocystic serous adenoma of the pancreas: radiologic-pathologic correlation

OBJECTIVE

Macrocystic serous adenoma is a rare benign pancreatic neoplasm, recently described in the pathology literature. We describe the CT and MR imaging features in a series of five consecutive pathologically proven cases.

MATERIALS AND METHODS

Of seven cases fulfilling the pathology criteria for macrocystic serous adenoma over an 11-year period, five patients underwent preoperative CT and MR imaging at our institution. In addition to the clinical presentation and pathologic features of the tumor, the following CT and MR imaging features were reviewed: size and location; wall thickness; internal septations; and presence of mural nodules, papillary projections, or calcifications.

RESULTS

All patients but one were women (age range, 36-78 years; mean age, 48.6 years). The sizes of the tumors ranged from 1.5 to 5.0 cm (mean, 3.1 cm). Three (60%) of five tumors were located in the pancreatic head. The wall measured less than 2 mm in four lesions and 4 mm in one. No mural nodules, papillary projections, or calcifications were present. Lesions were unilocular (n = 3) or bilocular (n = 2). Excellent correlation of imaging features with gross pathology was observed.

CONCLUSION

On CT and MR imaging, the macrocystic variant of serous adenoma typically appears as a small (< 5 cm), uni- or bilocular cyst with a thin (< 2 mm) wall that lacks mural nodules or calcifications. The imaging appearance of macrocystic serous adenoma is distinctly different from that of microcystic serous cystadenoma, but the imaging appearance of macrocystic serous adenoma is indistinguishable from mucinous cystadenoma and cystadenocarcinoma of the pancreas.

[Unilocular macrocystic serous cystadenoma of the pancreas: a morphologic variant to be considered]

Serous cystadenoma of the pancreas is a benign cystic tumor, which radiological diagnosis is easy in its typical microcystic variant. The macrocystic variant is uncommon and raises diagnostic problems with other macrocystic lesions of the pancreas such as pseudocysts and mucinous cystadenomas. We report the case of a young woman with a unilocular macrocystic serous cystadenoma of the pancreas which was identified on pathologic examination of the surgical specimen, after unconclusive abdominal ultrasound and CT-scan. This case describes an unusual clinical presentation of this cystic tumor and emphasizes that the diagnosis of such an entity is still based on pathological examination after cyst removal.

Macrocystic form of serous pancreatic cystadenoma

OBJECTIVES

Macrocystic serous cystadenoma of the pancreas are benign lesions with sometimes difficult diagnostic issues. We aimed to describe clinicopathological and imaging features with cyst fluid analysis in a series of patients undergoing surgery for macrocystic serous cystadenoma.

METHODS

Eight patients underwent pancreatic resection for a macrocystic lesion of the pancreas diagnosed on ultrasonography or CT. Endoscopic ultrasonography and preoperative fine-needle aspiration were performed in seven patients. Immunohistochemical analysis of the surgical specimen with antibodies to carcinoembryonic-antigen (CEA), carbohydrate antigen (CA) 19-9, estrogen receptor, and progesterone receptor antibodies was performed in all cases.

RESULTS

Patients included seven women and one man, with a mean age of 48 yr. Lesions were incidentally discovered on ultrasonography in six patients and had a mean size of 3 cm (range, 1.5-5 cm). Endoscopic ultrasonography revealed millimetric cysts in three cases. In the seven aspirated cysts, cytological analysis was non-contributive, but biochemical analysis showed low content of CEA (< 5 ng/ml) and CA72.4 (< 40U/ml) in all but two. At histology, cysts were lined by clear cuboidal cells. They focally expressed CA19-9 but were negative for anti-CEA, antiestrogen receptor, and antiprogesterone receptor antibodies. Microscopic cysts in the wall of the lesions were demonstrated in five cases.

CONCLUSIONS

Macrocystic serous cystadenoma is a particular variant of pancreatic serous cystadenoma. Endoscopic ultrasonography may be useful in detecting peripherally located millimetric cysts in unilocular lesions, and measurement of enzymes and tumor markers in cyst fluid may also contribute to the diagnosis showing low concentrations.

Role of endoscopic ultrasound in the diagnosis of cystic lesions of the pancreas

Endoscopic ultrasound (EUS) is an ideal imaging technique for pancreatic cystic lesions. Ultrasound is exquisitely sensitive for detecting and characterizing cysts arising in solid organs, and when the transducer is placed on an endoscope, high resolution imaging of the pancreas is achieved. Linear EUS can also guide needle aspiration of pancreatic cystic lesions and through the use of aspiration cytology, cystic tumors of the pancreas can be diagnosed. Since cytology is a relatively insensitive test, cyst fluid tumor markers such as CEA have been employed to improve the sensitivity for the detection of malignancy. Cyst fluid CEA values are uniformly low in serous cystadenomas, higher in mucinous lesions, and markedly elevated in mucinous cystadenocarcinomas. Through the use of these techniques, the ability to detect and diagnose early malignancies of the pancreas will be greatly enhanced.

Serous oligocystic adenoma of the pancreas: a clinicopathological and immunohistochemical study of three cases with ultrastructural findings

AIMS

Serous oligocystic adenoma of the pancreas is an uncommon benign neoplasm and is a recently described entity. To date, there are 19 adult cases of this tumour. We report three additional cases, two with macrocystic and one with unilocular types. We describe their clinicopathological, immunohistochemical and ultrastructural findings and review the world's literature.

METHODS

For a 10-year period, we reviewed all benign cystic lesions of the pancreas with emphasis on serous oligocystic adenoma. We characterised serous oligocystic adenoma as an ill-demarcated or encapsulated mass, composed largely or exclusively of macrocysts (cysts measuring 20mm or more) but few in number (oligolocular). Grossly, it may contain only a single cyst (unilocular) of any size with a few satellite cysts observed on histological examination. Special stains and immunohistochemistry as well as electron microscopy were performed on three and two cases of serous oligocystic adenoma, respectively.

RESULTS

Between 1990 and 2000, we collected 26 benign cystic lesions of the pancreas, three of which were serous oligocystic adenomas (two with macrocystic and one with unilocular types). Many of the cells lining the cysts showed PAS positivity. There was negative staining for PAS with diastase digestion, Alcian blue and mucicarmine. All cases showed positive staining for CAM5.2, AE1/AE3, EMA and CK7. The proliferation index marker was low. There was negative staining for CK20, insulin, glucagon, somatostatin, synaptophysin, chromogranin A, CEA and p53. Ultrastructural studies on two cases revealed similar findings. The single row of uniform epithelial cells lining the cysts was composed of simple cuboidal to flat cells which rested on a thin basal lamina. Their nuclei were round to ovoid. Glycogen granules were identified in the cytoplasm. Short microvilli emerged from the epithelial apical surface. Adjacent tumour cells were connected by microfilaments.

CONCLUSIONS

Serous oligocystic adenomas of the pancreas are uncommon benign tumours. Prior to this study, 19 adults with these lesions were reported in the world's literature. No correct pre-operative diagnosis was carried out on all 22 cases. The 20 patients with follow-up ranging from 2 months to 5 years did not show tumour recurrence or malignant transformation.