Macrocystic Serous Cystadenoma Research Articles

Preoperative differentiation of pancreatic mucinous cystic neoplasm from macrocystic serous cystic adenoma using radiomics: Preliminary findings and comparison with radiological model

PurposeTo develop a radiomics model in the preoperative differentiation of mucinous cystic neoplasm (MCN) and macrocystic serous cystadenoma (MaSCA) and to compare its diagnostic performance with conventional radiological model. Methods57 Patients (MCN = 31, MaSCA = 26) with preoperative multidetector computed tomography (MDCT) scans were retrospectively included in this study. A radiological model was constructed from radiological features evaluated by radiologists. A radiomics model was constructed with high-dimensional quantitative features extracted from manually segmented volume of interests (VOIs). A combined model was constructed using both radiomics features and radiological features. The diagnostic performance of three models were assessed by the area under the receiver-operating characteristic curve (AUC), sensitivity, specificity, accuracy, and the calibration curves. ResultsThe radiological model yielded an AUC of 0.775, sensitivity of 74.2 %, specificity of 80.8, and accuracy of 77.2 %. The radiomics model yielded an AUC of 0.989, sensitivity of 93.6 %, specificity of 96.2 %, and accuracy of 94.7 %. The combined model yielded an AUC of 0.994, sensitivity of 96.8 %, specificity of 100 %, and accuracy of 98.2 %. Both combined model and radiomics model showed higher AUC, sensitivity, and accuracy than radiological model (all P < .05). The combined model showed higher AUC than radiomics model, though no significant difference was found (P = .41). The combined model showed better calibration than radiomics model (P = .91 vs. P < .001). ConclusionsCombined model which contained both radiomics features and radiological features outperformed radiomics model and radiological model in the preoperative differentiation of MCN and MaSCA.

Tumor growth rate of pancreatic serous cystadenomas: Endosonographic follow-up with volume measurement to predict cyst enlargement

BackgroundSerous cystadenomas are benign lesions of the pancreas. Usually they are diagnosed incidentally on cross-sectional imaging studies. Endosonography is a valuable tool in the diagnosis and follow-up of these cystic lesions. Given its benign nature, surgical resection is advised only in symptomatic patients. The interval and length of surveillance is not well established. MethodsA retrospective single center study was done. All the patients with a pancreatic serous cystadenoma sent for an endosonographic evaluation, between December 2008 and December 2015 were included. The lesions were follow-up endosonographically at least once, in a 12 months interval. Volume was measured with the formula π/6 × (d1 x d1 x d2). Two groups were evaluated: patients with a volume under 10 mL (Group 1) and those with a volume of 10 mL or more at presentation (Group 2). Growth rate between these two groups was compared. ResultsThirty-one patients were analyzed, with a mean age of 58.2 years. Patients were mainly women (87%). Twenty-four patients in Group 1 had a mean enlargement of 0.67 ml per year, whereas patients in Group 2 had a mean enlargement of 9.8 ml per year. The growth rate difference between these two groups was statistically significant (p = 0.0001). ConclusionAsymptomatic patients with pancreatic serous cystadenomas should be follow-up for enlargement. Small volume lesions have a low risk of enlargement compared with high volume and macrocystic serous cystadenomas. Volume at presentation is a feature to analyze when defining surveillance interval.

Kyste mucineux simple du pancréas : description d’un cas et revue de la littérature

Simple mucinous cyst of the pancreas is an unusual pancreatic cyst, first described by Kosmahl et al. in 2002with 5cases. We describe a case of simple mucinous cyst of the pancreas, followed by a literature review. The physiopathology of this cyst is still unclear. It is an epithelial cyst, presenting as unilocular cystic lesion of the pancreatic body or tail, with a clear content, and no communication with the pancreatic duct. Microscopically, the cyst is lined by mucin-producing cells with mild atypia, and contains a fibrous wall without ovarian-like stroma. The prognosis is excellent, as no recurrent disease and progression to malignancy have been described. The non neoplastic origin of this lesion is debated, as cases with KRAS mutation and intra-epithelial neoplastic lesions have been recently reported. It is important to distinguish this lesion from macrocystic serous cystadenoma, mucinous cystic neoplasms and intraductal papillary mucinous neoplasms, by clinical, radiological and pathological features, as the treatment varies from simple surveillance to surgical resection.

Noncommunicating cystic pancreatic lesions (i.e. serous and mucinous cystadenoma + rare lesions)

Mucinous cystic neoplasm (MCN) occurs predominantly in women (>95%) with a mean age of approximately 45 years and most commonly is located in the pancreatic body or tail. The mass is lined by mucin-producing columnar epithelium with a fibrous ovarian-type stroma. The epithelial lining can contain various degrees of atypia, ranging from adenoma to invasive carcinoma. The CT and MR appearance is that of at hick walled cystic mass with septa and/or mural nodules. The contour of the mass is smooth, and the wall or septa may contain calcification. Endoscopic ultrasound with fine needle aspiration of the cyst fluid to assess CEA level may be helpful in distinguishing MCN from serous cystadenoma. CEA 192 ng/mL favors MCN, with an accuracy of approximately 80% [1]. The overall risk of malignancy in one series was 17.5%, and all malignant tumors were either >4 cm or contained mural nodules [2]. Treatment of MCN is surgical resection, and patients without extracapsular or diffuse intracapsular infiltration have an excellent prognosis [2]. Serous cystadenoma (SCA) also occurs predominantly in women (approximately 75%), but the mean age is older (mid 50s to early 60s). It is lined by glycogen-rich cuboidal epithelium and is considered a benign neoplasm, although rare cases of malignant SCA have been reported. The typical appearance is that of a lobulated mass consisting of numerous tiny cysts which give it a honeycomb appearance. Larger lesions may contain a central stellate scar and calcifications. Oligocystic or macrocystic SCA is an uncommon variant comprised of a small number of larger cysts. Distinction between macrocystic SCA and MCN can be made based on the lobulated contour of SCA, its multiple clustered cyst configuration and homogeneity of each locule on T1 weighted MR images [3]. Surgical resection generally is reserved for symptomatic patients, although some authors recommend periodic imaging to assess the rate of growth, with consideration given to surgical resection of lesions with doubling time of 80%), with a median age 30-38 years [5,6]. It is not a true cystic neoplasm in that the cystic component lacks an epithelial lining. Rather, the cystic component represents necrotic degeneration of the mass, with various amounts of internal blood and debris. SPN appears as a well-circumscribed round or oval thick-walled mass with solid and cystic components, but it can appear completely solid or completely cystic. CT demonstrates calcification in nearly half of SPNs [6]. MR often demonstrates a thick T2 hypointense or enhancing rim and internal blood products. Treatment is surgical resection, and the prognosis is excellent, with metastases developing in <5% of patients [6]. Cystic neuroendocrine neoplasm of the pancreas most commonly occurs in patients with multiple endocrine neoplasia type I and usually is nonfunctional [7]. It generally appears as a cystic mass with an enhancing rim and may contain septa or a solid component. Treatment usually is surgical resection, although observation may be a viable alternative approach [8].

Unusual case of a giant serous oligocystic adenoma with communication to main pancreatic duct

Benign serous cystic tumors of the pancreas are rare and include microcystic serous adenoma, serous oligocystic adenoma (SOA), ill-demarcated adenoma, and macrocystic serous cystadenoma. Microcystic serous adenoma usually present are either unilocular cyst or single lesion containing fewer cysts of more than 2 cm in diameter. It is a rare tumor which usually varies from 210 cm in size and at times difficult to differentiate from mucinous cyst. With firm diagnosis small asymptomatic SOAs could be managed without surgery. We describe here a case of middle aged male with a giant serous oligocystic adenoma of 15 cm size arising from head of pancreas producing pressure symptoms. Endoscopic ultrasound and cyst fluid tumor markers were suggestive of serous cystadenoma, computed tomography (CT) and magnetic resonance cholangiopancreatography (MRCP) scan were indicative of mucinous adenoma showing unilocular cyst with dilated common bile duct (CBD), main pancreatic duct (MPD) and communication of cyst with main pancreatic duct. A pancreaticoduodenectomy was done. Histopathology reported the lesion as serous oligocystic adenoma. We are presenting this case due to unusual features, a large unilocular cyst of more than 15 cm in size presented with waxing/waning of surgical obstructive jaundice and on MRCP there was a communication of cyst with MPD with cyst wall thickness of 1 cm (approx.).

Microcystic Serous Cystadenoma of the Pancreas With Subtotal Cystic Degeneration

Pancreatic serous cystadenomas are benign cystic neoplasms. Extensive degeneration mimicking a pancreatic pseudocyst has been described in several types of pancreatic neoplasms but has not been documented in serous cystadenomas. We report subtotal cystic degeneration of microcystic serous cystadenomas (MSCA) that produces radiographic, gross, and microscopic overlap with pancreatic pseudocyst. Resected MSCA with degenerative change were identified from the pathology archives of Memorial Sloan-Kettering Cancer Center and Johns Hopkins Hospital. The clinical, radiographic, gross, and microscopic findings were reviewed. Eight MSCAs with subtotal cystic degeneration were retrieved from among 397 resected serous cystadenomas (2.0%). There were 2 men and 6 women (mean age, 52 y). Available radiographic studies showed classic features of MSCA in 2 of 4 cases. Four cysts were unilocular, and 4 were multilocular. Gross features of MSCA were noted focally in the multilocular cases but were not evident in the unilocular examples. The predominant histologic features were those of pancreatic pseudocyst, including a fibrotic cyst wall lacking epithelium and instead composed of myofibroblastic proliferation, hemorrhage, and inflammation. Residual foci of MSCA were embedded in fibrosis, comprising 5% to 60% of the tumor volume. Most pancreatic serous cystadenomas display characteristic morphology, including a glycogen-rich epithelial lining and prominent subepithelial capillaries; however, extensive degenerative macrocystic change can obscure these classic features. This phenomenon is to be distinguished from macrocystic serous cystadenoma, in which thin-walled macrocystic spaces are epithelium lined. Thus, serous cystadenoma should be included in the differential diagnosis of pancreatic masses with extensive degenerative cystic change.

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, ≤1 mm; thick, >1 mm), internal surface (smooth or irregular), and other findings were analyzed with multiphasic CT with thin-section (2.5–3 mm) 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.

Can EUS Help Differentiate Macrocystic Serous Cystadenomas from Mucinous Cystadenomas of the Pancreas by Its Morphologic Characteristics?

Background/Aims: Benign pancreatic serous cystadenoma is usually distinguishable from mucinous cystadenoma (MCA), which requires resection because of its malignant potential. Macrocystic serous cystadenoma (M-SCA), a macrocystic variant of serous cystadenoma which is hard to distinguish from MCA, has recently been described. The aim of this study was to describe the morphologic characteristics of M-SCA with EUS, in order to differentiate M-SCA from MCA. Subjects and Methods: Clinical and morphologic characteristics on EUS were reviewed from 31 consecutive patients with M-SCA or MCA who had undergone surgery. Results: Resected specimens were available for 11 M-SCAs and 20 MCAs. Significant differences in characteristics were observed with age (44 years old, 26–58 for M-SCA vs. 57 years old, 31–68 for MCA, p=0.011) and location within the pancreas (64% in head for M-SCA vs. 85% in body or tail for MCA, p=0.013). No significant differences on EUS were observed between both groups regarding the type of loculation, cyst wall, and echo-pattern of cyst contents. But, many cases of M-SCA had microcysts (82%) when compared with 15% of MCA (p<0.001), and lobulated configuration of cyst was more frequently seen in M-SCA than MCA (91% vs. 25%, p=0.001). The combination of microcysts and lobulated configuration of cyst had sensitivity of 90%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 95% for the diagnosis of M-SCA when compared with MCA. Conclusions: M-SCA tends to occur at a relatively younger age than MCA and locate mainly in the head of the pancreas. While conventional imaging modalities display considerable morphologic overlap between M-SCA and MCA, EUS reveals characteristic findings including microcysts and lobulated configuration of cyst, which may help differentiate M-SCA from MCA.

Successful Cystic Fenestration for a Macrocystic Serous Cystadenoma of the Pancreas Causing Obstructive Jaundice: Report of a Case

A 72-year-old man was admitted to our hospital for investigation of jaundice. We made a preoperative diagnosis of macrocystic serous cystadenoma (SCA) of the pancreas, but did not perform palliative choledochojejunostomy because aspiration of the pancreatic cystic fluid caused the cysts to shrink and relieved the compressive stenosis of the common bile duct (CBD) during the operation. Frozen sections of the cyst wall taken by incision biopsy showed no signs of malignancy. Therefore, we performed fenestration of the cystic wall after fixing the inner epithelium of the cyst with 100% ethanol and aspirating the cystic fluid. Cholangiography after the cystic fenestration showed resolution of the CBD stenosis and abdominal computed tomography (CT) confirmed the disappearance of the pancreatic cysts. No recurrence of cystic swelling or obstructive jaundice has been detected by abdominal CT or laboratory data for more than 2 years since the cystic fenestration. Thus, cystic fenestration may be a better palliative option for treating benign compressive tumors such as macrocystic SCA of the pancreas causing obstructive jaundice.

Cystic lesion of the pancreas

Cystic lesion of the pancreas

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.

Discrimination of Unilocular Macrocystic Serous Cystadenoma from Pancreatic Pseudocyst and Mucinous Cystadenoma with CT: Initial Observations

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

Le cystadénome séreux macrokystique uniloculaire du pancréas : une variante morphologique à connaître

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 noncontributive, 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, anti-estrogen receptor, and anti-progesterone 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.

Macrocystic form of serous pancreatic cystadenoma.

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. 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. 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. 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.

Mixed Microcystic and Macrocystic Serous Cystadenoma of the Pancreas: A Case Report

Mixed Microcystic and Macrocystic Serous Cystadenoma of the Pancreas: A Case Report

Macrocystic Serous Cystadenoma of the Pancreas

Abstract: The case of a 61 ‐year‐old man with macrocystic serous cystadenoma of the pancreas is reported. Abdominal ultrasonography and computerized tomography showed a multilocular cystic lesion in the body of the pancreas. The major cysts ranged in size from more than 2.0 cm up to 6.0 crn. Endoscopic ultrasonography (EUS) showed a few small cysts in addition to the large cysts. The preoperative diagnosis was either mucinous cystic tumor or congenital cyst of the pancreas and tumor enucleation was performed. Histological examination revealed serous cystadenoma of the pancreas with macrocysts. Detecting small cysts with EUS may be useful for distinguishing this unusual tumor from mucinous cystic tumors.

A case of macrocystic serous cystadenoma of the pancreas

A case of macrocystic serous cystadenoma of the pancreas is presented, and literature is reviewed. A 35-yr-old woman presented with mild upper abdominal pain. Abdominal ultrasonography and an abdominal computed tomography revealed a multiloculated and calcified cyst in the body of the pancreas. A T1-weighted image, using magnetic resonance imaging, revealed a low-intensity multiloculated, pancreatic mass. In contrast, T2-imaging of the tumor showed a high-intensity mass. Endoscopic retrograde cholangiopancreatography showed no contact between the main pancreatic duct and the tumor. The preoperative diagnosis was a mucinous cystic neoplasm. Tumor enucleation was performed. Subsequent microscopic examination of this tumor suggested the diagnosis of a macrocystic serous cystadenoma of the pancreas.

Macrocystic serous cystadenoma of the pancreas: A morphologic variant differing from microcystic adenoma

The term “microcystic adenoma” of the pancreas has gained nearly universal acceptance among pathologists owing to the characteristic gross and microscopic features of this tumor. The possible existence of macrocystic variants of serous cystadenoma has been largely ignored in the literature. We report five cases of macrocystic serous cystadenoma of the pancreas, two of which were of the unilocular type. These tumors exhibited distinctly different macroscopic features from microcystic adenoma, which created diagnostic difficulties for both the radiologist and pathologist. Computed tomography scans on all five cases were thought to represent either mucinous cystic neoplasms or pseudocysts and the tumors were misclassified in two of three cases on which intraoperative frozen sections were performed. In our opinion, microcystic and macrocystic serous tumors represent morphologic variants of the same benign pancreatic neoplasm and we suggest that the term “serous cystadenoma” be used to encompass all variants of this benign neoplasm.