Computed tomography and fine-needle aspiration cytology for preoperative evaluation of cystic tumours of the pancreas

Fine-needle aspiration of pancreatic serous cystadenoma: cytologic features and diagnostic pitfalls

BACKGROUND

The preoperative diagnosis of pancreatic serous cystadenoma (SCA) is important because as a typically benign tumor it can be treated expectantly, whereas many other cystic tumors require excision. This study examines the cytology, clinical and radiologic features, diagnostic accuracy of fine-needle aspiration (FNA), and potential pitfalls associated with this rare tumor.

METHODS

Cytomorphologic features were retrospectively reviewed from 28 FNAs of SCA from 21 patients. FNA biopsies were guided by percutaneous computed tomographic or ultrasonographic imaging in 10 cases and by endoscopic ultrasonographic imaging in 18 cases. Corresponding histology (14 tumors) and clinical/imaging findings were also evaluated.

RESULTS

Patients typically presented with upper abdominal discomfort or asymptomatically. Radiologically, a well-demarcated, multiloculated cystic mass involving the pancreatic head or uncinate process was common. Aspirates were sparsely cellular against a clean or granular, proteinaceous background. Tumor cells formed loose clusters or monolayered sheets composed of cuboidal cells with indistinct cell borders and granular or clear cytoplasm that was often stripped from the nucleus. Nuclei were small, round, with fine chromatin and indistinct nucleoli and devoid of mitotic activity. Seven (25%) of the aspirates were initially classified as "consistent with SCA," 6 (21%) as "no malignant cells," 3 (11%) as "nondiagnostic specimen," 3 (11%) as "suspicious for malignancy," 3 (11%) as "rare atypical cells," and 6 (21%) as "probably or consistent with mucinous cystic neoplasm." Features causing diagnostic difficulty were scant cellularity, papillary groups, nuclear atypia, and columnar cells mimicking those of mucinous neoplasms. Gastrointestinal (GI) epithelium and mucin also caused confusion. The detection of intracytoplasmic glycogen (3 of 6 cases) and cyst fluid analysis (2 of 2 cases) showing low viscosity and low or undetectable levels of carcinoembryonic antigen, CA 19.9, and amylase enhanced diagnostic confidence.

CONCLUSIONS

Diagnosing SCA by FNA is challenging. Familiarity with its morphologic spectrum, use of ancillary studies, and correlation with clinical/radiologic findings greatly improves diagnostic accuracy. Contaminating GI epithelium and mucin should be distinguished from components of a mucinous neoplasm.

True Solitary Pancreatic Cyst in an Adult: Report of a Case

The differential diagnosis of cystic neoformations in the pancreas is challenging. We report a case of a true solitary cyst of the pancreas in a 26-year old woman. Abdominal magnetic resonance imaging and computed tomography showed a unilocular neoformation in the head of the pancreas, without obstruction of Wirsung's duct. We excised the cyst and performed Roux-en-Y loop pancreaticojejunostomy, but the patient suffered recurrent acute pancreatitis from Wirsung's duct stenosis. Thus, a new Roux-en-Y loop pancreaticojejunostomy was successfully done 6 months later. Histologically, the cyst was lined by cuboidal epithelium, immunohistochemically positive to anti-carbohydrate antigen 19-9 antibodies. To our knowledge, only 11 cases of solitary true cyst of the pancreas in adults have been reported, so the characteristics of this unusual entity are not well known. We propose a scheme for the differential diagnosis of cystic neoformations of the pancreas, starting from the histopathological definition of a true solitary cyst.

Microcystic adenoma of the pancreas

BACKGROUND

Cytology literature on pancreatic microcystic adenoma is sparse. It is important to separate microcystic adenoma from adenocarcinoma and mucinous cystic neoplasms on aspiration cytology, because patients with microcystic adenoma can be treated conservatively unless they are symptomatic. Potential pitfalls with endoscopic ultrasound (EUS) sampling of these lesions is discussed.

METHODS

From January 1991 through June 2003, 10 patients with microcystic adenoma of the pancreas were diagnosed on fine-needle aspiration cytology. An additional patient, who was diagnosed with a mucinous cystic neoplasm by EUS sampling, was rediagnosed with microcystic adenoma on the excised specimen. Aspirate smears, cell blocks, core biopsies, subsequent excision (if any), and special stains were reviewed. Imaging studies and clinical data were available from the majority of patients.

RESULTS

CLINICAL RESULTS

The patients included 5 females and 6 males who ranged in age from 45 years to 84 years. Radiology studies showed tumors, which were heterogeneous with areas of fluid density and septations, located in the head, body, or tail of the pancreas. The masses ranged in size from 1 cm to 17 cm. The radiographic impression was highly suggestive of microcystic adenoma in six patients; detailed radiologic information was not available from three patients. On follow-up, six patients were alive and well at the last follow-up available, two patients died of unrelated sepsis, and three patients were lost to follow-up. Three of 11 patients underwent a Whipple resection. Cytology results: The cytologic features identified included the following: 1) Bland tumor cells were seen in sheets or small groups with a lack of nuclear abnormalities and moderate-to-scant cytoplasm with occasional clearing or vacuolation. Naked nuclei were present occasionally. Tumor cells were distinguishable from acinar cells based on larger cell size and granular cytoplasm in which prominent nucleoli were seen. 2) Relatively acellular, fibrovascular stroma was seen, usually located between tumor cells. 3) Calcifications were seen in four of eleven tumors. One tumor sampled by EUS revealed fragments of glandular-type epithelium with minimal atypia and was diagnosed erroneously as a mucinous cystic neoplasm. Cell blocks or core biopsies from most tumors showed fragments of dense stroma and cystic spaces lined by flattened epithelial cells. Subsequent Whipple resection in three patients showed histologic features of microcystic adenoma. Special stains performed in select tumors were positive for cytokeratin, carbohydrate antigen 19.9, and periodic acid-Schiff stain. Calretinin staining was negative in the tumor cells.

CONCLUSIONS

A cytologic diagnosis of microcystic adenoma is possible based on the criteria described above. Cell block and/or core biopsy, special stains, and radiologic information are key in making a definitive diagnosis. Patients with microcystic adenoma are spared a major surgical procedure unless they are symptomatic. With the EUS-guided modality of pancreatic sampling, caution should be exercised in misinterpreting benign glandular epithelium derived from the stomach or small bowel as a mucinous cystic neoplasm.

Management of cystic tumours of the pancreas

BACKGROUND

Cystic tumours of the pancreas account for 5% of pancreatic neoplasms and are frequently misdiagnosed as pancreatic pseudocysts. The authors' experience of managing these tumours is presented here, highlighting the clinical presentation, diagnostic difficulties and operative treatment.

METHODS

This is a retrospective study of all patients diagnosed to have cystic tumours of the pancreas treated at The Mater Hospital, during a 5-year period from 1997 to 2002. Literature was reviewed and guidelines for the management of these tumours have been outlined.

RESULTS

Seven patients with cystic pancreatic tumours were treated over this time-period. All patients were women with a median age of 40. Two of these patients were initially diagnosed as having pseudocysts and were treated elsewhere by cystgastrostomy. The tumour was resected in all patients. All but one was benign. At follow up, ranging from 13 to 66 months, all patients were alive and well.

CONCLUSIONS

Cystic tumours of the pancreas are uncommon and generally slow growing. It is important not to assume that a cystic lesion in the pancreas, especially in middle-aged women, is a pseudocyst. Satisfactory surgical resection may be possible even after previous operative procedures on the pancreas. Prognosis after resection remains good.

Macrocystic serous adenoma of the pancreas

Macrocystic serous adenoma of the pancreas (MSAP) is a rare neoplasm. Its preoperative diagnosis by physical examination and imaging studies is challenging, if not impossible. In recent years, a few cases of MSAP with correct cytodiagnosis by transabdominal fine-needle aspiration (TFNA) have been documented. This paper reports two cases of MSAP that were successfully diagnosed by TFNA cytology. Two adult women presented with epigastric discomfort. Abdominal imaging studies revealed a large pancreatic cystic lesion in both cases. TFNAs of the pancreatic lesions were subsequently performed and revealed a clear serous fluid containing small monolayered sheets of benign cuboidal epithelial cells with scant, clear or granular cytoplasm, vesicular nuclei and micronucleoli. The cell cytoplasm stained positively with periodic acid-Schiff (PAS) and negatively with PAS with prior digestion with diastase (PASD). The cytological findings in both cases were similar and suggested a serous cystadenoma. The two pancreatic lesions were removed by Whipple's operation. They showed features of a macrocystic serous adenoma of the pancreas that were characterized by a small number of large cystic cavities lined by a single layer of non-mucus secreting, PAS-positive and PASD-negative cuboidal epithelial cells. By electron microscopy, the epithelial lining cells showed short and aborted apical microvilli, well-formed desmosomes and a large amount of intracytoplasmic glycogen, suggesting a centroacinar ductal cell origin.

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.

Macrocystic serous cystadenoma of the pancreas: clinicopathologic features in seven cases

BACKGROUND

Serous cystic neoplasms of the pancreas are uncommon tumors classified as microcystic adenomas. In this article, the authors report clinico-pathologic features of seven cases of macrocystic variant of the serous cystadenoma.

METHODS

Seven patients (5 females and 2 males) with a diagnosis of cystic lesion of the pancreas were observed after 1995. Clinical, radiological, and pathologic features, including immunohistochemistry, were reported. Enzymes and tumor markers CEA, CA 19-9, CA 125, CA 15-3, CA 72-4, and mucin-like carcinoma-associated antigen (MCA) were investigated in the serum and cyst fluid of the patients. Cytology was also performed.

RESULTS

Six patients were symptomatic complaining abdominal pain. All cases had radiologic evidence of unilocular cyst of the pancreas. The suspected diagnosis was consistent with mucinous cystic neoplasm. Serum tumor markers were all in the normal range. After surgery, pathology showed in all cases a cyst lined with cuboidal, periodic acid-Schiff (PAS)-positive epithelium, without mucin content or atypia. Minute microcysts were found surrounding the main cavity. Immunohistochemical stains were positive for cytokeratin, CA19-9, CA15-3, CA 72-4, and MCA. CEA was unexpressed. CA 125 in the cyst fluid were found elevated in three cases and CA 19-9 in three cases. Cytology was negative in all cases.

CONCLUSION

When a unilocular pancreatic cyst is found, without history of pancreatitis and gallstones, having low serum tumor markers levels and negativity of CA 72-4 and MCA in the cyst fluid, the diagnosis of the macrocystic variant of the serous cystadenoma may be suggested. At present, the diagnosis is still based on pathological examination after cyst removal.

Mucinous cystic neoplasm (mucinous cystadenocarcinoma of low-grade malignant potential) of the pancreas: a clinicopathologic study of 130 cases

Mucinous cystic neoplasms (MCNs) of the pancreas are uncommon tumors. The classification and biologic potential of these neoplasms remain the subject of controversy. Attempts to classify these tumors in a similar manner to ovarian MCNs remains controversial, as even histologically benign-appearing pancreatic MCNs metastasize and are lethal. One hundred thirty cases of MCNs were identified in the files of the Endocrine Pathology Tumor Registry of the Armed Forces Institute of Pathology from the years 1979 to 1993. The pathologic features, including hematoxylin and eosin staining, histochemistry, immunohistochemistry (IHC), cell cycle analysis, and K-ras oncogene determination were reviewed. These findings were correlated with the clinical follow-up obtained in all cases. There were 130 women, aged 20-95 years (mean age at the outset, 44.6 years). The patients had vague abdominal pain, fullness, or abdominal masses. More than 95% of the tumors were in the pancreatic tail or body and were predominantly multilocular. The tumors ranged in size from 1.5 to 36 cm in greatest dimension, with the average tumor measuring >10 cm. A spectrum of histomorphologic changes were present within the same case and from case to case. A single layer of bland-appearing, sialomucin-producing columnar epithelium lining the cyst wall would abruptly change to a complex papillary architecture, with and without cytologic atypia, and with and without stromal invasion. Ovarian-type stroma was a characteristic and requisite feature. Focal sclerotic hyalinization of the stroma was noted. This ovarian-type stroma reacted with vimentin, smooth muscle actin, progesterone, or estrogen receptors by IHC analysis. There was no specific or unique epithelial IHC. K-ras mutations by sequence analysis were wild type in all 52 cases tested. Ninety percent of patients were alive or had died without evidence of disease (average follow-up 9.5 years), irrespective of histologic appearance; 3.8% were alive with recurrent disease (average 10 years after diagnosis); and 6.2% died of disseminated disease (average 2.5 years from diagnosis). Irrespective of the histologic appearance of the epithelial component, with or without stromal invasion, pancreatic MCNs should all be considered as mucinous cystadenocarcinomas of low-grade malignant potential. Pancreatic MCNs cannot be reliably or reproducibly separated into benign, borderline, or malignant categories.

Ultrasound-guided fine needle biopsy of pancreatic masses: results of a multicenter study

OBJECTIVE

The aim of this study was to investigate the results of ultrasound-guided fine needle biopsy of pancreatic masses in a large multicenter series.

METHODS

This study collected the data of 510 patients who had a final diagnosis available and who had undergone ultrasound-guided fine needle biopsy of the pancreas. Retrieval rate, sensitivity, specificity, and overall diagnostic accuracy of the whole series, by three different bioptic procedures (cytology, histology, and cytology plus histology) were evaluated. The reliability of ultrasound-guided fine needle biopsy to allow a correct diagnosis in the different pancreatic pathologies was calculated. Finally, any complications were collected.

RESULTS

For cytology, histology, and cytology plus histology, retrieval rate values were: 94%, 96%, and 97%; sensitivity was: 87%, 94%, and 94%, specificity: 100%; and diagnostic accuracy: 91%, 90%, and 95%, respectively. Ultrasound-guided fine-needle biopsy correctly diagnosed all the cases of pancreatic metastases or non-Hodgkin's lymphoma (23 of 510 cases as 5%; in eight of 23 it led to the first diagnosis of the primary tumor) and all the cases of abscesses, 97% of the cases of pseudocysts, 86% of pancreatic adenocarcinomas, 62% of cystic neoplasms, 35% of the cases of chronic pancreatitis (in this case, the bioptic procedures were reviewed), and 33% of neuroendocrine tumors. There were complications in one case of asymptomatic peripancreatic hematoma, three cases of vaso-vagal reactions, and 21 cases of pain.

CONCLUSION

Ultrasound-guided fine needle biopsy of the pancreas is efficacious, without any difference between the various bioptic modalities (with the exception of chronic pancreatitis, in which histology is better). The technique is safe. Moreover, the procedure allows the identification of patients affected by pancreatic tumors other than adenocarcinoma (in our survey 5% of the total); in about one third of these patients it leads to the diagnosis of the primary tumor, thus avoiding inappropriate treatments.

K-ras oncogene mutations indicate malignancy in cystic tumors of the pancreas

OBJECTIVE

To evaluate clinical parameters, presurgical diagnostic tests, histologic findings, and the presence of K-ras oncogene mutations in cystic tumors of the pancreas to determine which best predict malignancy.

SUMMARY BACKGROUND DATA

Because presurgical, intraoperative, and final pathologic differentiation is difficult in cystic tumors of the pancreas, it would be a major benefit to identify markers that accurately predict malignancy in these rare tumors. The role of K-ras oncogene mutations as an indicator of malignancy has not been determined in these tumors.

METHODS

Nineteen patients with cystic tumors of the pancreas were evaluated, including K-ras mutation analysis based on polymerase chain reaction and restriction digestion assays and direct DNA sequencing, to screen for parameters that accurately predict malignancy.

RESULTS

All malignant cystic pancreatic tumors (five cystadenocarcinomas and three mucin-producing adenocarcinomas) harbored K-ras mutations at codon 12 or 13. K-ras mutations were also detected in the percutaneous fine-needle aspirates of two of these patients. In contrast, none of nine benign cystadenomas or the solid-papillary neoplasm had K-ras mutations. None of the patients with a benign tumor carrying K-ras wild-type sequences developed recurrent disease after a mean follow-up of 50 months. Seven of the 8 malignant cystic pancreatic tumors, but none of the 11 benign tumors, showed dilatation of the main pancreatic duct on computed tomography or endoscopic retrograde cholangiopancreatography.

CONCLUSIONS

K-ras mutation analysis seems to be a powerful tool to determine the malignant potential of cystic pancreatic tumors before and after surgery. Dilatation of the main pancreatic duct on computed tomography or endoscopic retrograde cholangiopancreatography is highly suggestive for malignancy in these rare tumors.

Serous cystadenoma of the pancreas with atypical cells. Case report

CONCLUSION

Serous cystadenomas of the pancreas may have the biologic ability to undergo malignant transformation.

BACKGROUND

It is generally recognized that: serous cystadenomas of the pancreas are benign and that their malignant potential is low.

METHODS

A serous cystadenoma of the pancreas was resected from a 53-yr-old woman. In the central portion of the tumor, papillary structures were found on the cyst wall. Immunohistologic studies using antibodies to carbohydrate antigen 19-9, carcinoembryonic antigen, and proliferating cell nuclear antigen were performed to determine the malignant potential of this tumor.

RESULTS

On histology, most tumor cells were positive for periodic acid-Schiff but were negative for periodic acid-Schiff after diastase digestion and Alcian blue, a staining pattern typical of serous cystadenomas. The cells found in the papillary structure of the cyst wall were mildly atypical. These cells were stained with antibodies to carbohydrate antigen 19-9, carcinoembryonic antigen, and proliferating cell nuclear antigen, indicating that the cells comprising the papillary structure were proliferating more rapidly than cells in other parts of the tumor and strongly suggesting that the cells are premalignant.

Serous cystadenoma of the pancreas: report of 30 cases with emphasis on the imaging findings

PURPOSE

Our goal was to evaluate retrospectively 30 cases of serous cystadenoma (SCA) to determine its main imaging features as well as to discuss the differential diagnosis problems versus the other cystic lesions of the pancreas.

METHOD

Thirty SCAs were analyzed; they were all benign lesions, proven at surgery. Twenty-three tumors were evaluated with US, 26 with CT, and 5 with MRI.

RESULTS

Three different morphostructural patterns were identified: microlacunar (n = 19), mixed (n = 6), and macrolacunar (n = 5). The diagnosis of SCA, possible in either the microlacunar or the mixed patterns, was achieved in 74% of cases with US (17/23) and in 61.5% with CT (16/26). Among the 19 patients evaluated with both modalities, the joint information allowed a correct diagnosis in 16 cases (84%). The five macrolacunar tumors were undistinguishable from other cystic masses of the pancreas.

CONCLUSION

The diagnosis of SCA can be considered certain in the microlacunar, likely in the mixed, and not possible in the macrolacunar type.

Serous cystadenocarcinoma of the pancreas

The mucinous type of cystadenoma of the pancreas is known to have malignant potential, whereas the serous type is believed to be benign. Therefore, the therapeutic strategies for serous cystadenomas are less aggressive than in mucinous cystadenoma, where complete operative resection is the procedure of choice. A patient with a biopsy-proven serous cystadenocarcinoma with a lymph node metastasis is reported. Considering the reported case and a review of the literature, the origin of serous cystadenocarcinoma appears to be from cystadenoma lesions. Even if this development of cystadenocarcinoma in pre-existing serous cystadenoma lesions is a rare entity, a less aggressive treatment of this lesion should be avoided in favor of resection procedures because of the good chance of cure.

Resection of the inferior head of the pancreas: report of a case

We developed a new technique for partial resection of the head of the pancreas with an end-to-side pancreaticoduodenostomy, while preserving the duodenum, the common bile duct, and the upper part of the head of the pancreas around the duct of Santorini. A resection of the inferior head of the pancreas was performed in a patient with an intraductal mucin-producing tumor of the pancreas. This procedure is considered to be appropriate for treating both benign disease and noninvasive malignant disease involving either the uncinate process or the duct of Wirsung, because it removes both the uncinate process and the pancreatic tissue around the duct of Wirsung. We thus believe that a resection of the inferior head of the pancreas with an end-to-side pancreaticoduodenostomy can help play a significant role in the management of patients with benign diseases and localized malignant tumors of the pancreas.

Serous cystadenoma of the pancreas communicating with a pancreatic duct

CONCLUSION

To differentiate serous cystadenoma from other cystic lesions communicating with the pancreatic duct, careful radiological examination is necessary.

BACKGROUND

Communication between the cystic cavity and the pancreatic duct in an ordinary serous cystadenoma is uncommon, although it is not uncommon in other cystic lesions, such as pseudocyst, mucinous cystadenoma/adenocarcinoma, and intraductal papillary tumor. METHODS. A serous cystadenoma of the pancreas communicating with main pancreatic duct in a 76-yr-old male is reported.

RESULTS

The communication was preoperatively demonstrated by endoscopic retrograde cholangiopancreatography and confirmed by histopathological examination of the resected specimen.

Solitary true cyst of the pancreas in adults. Report of three cases and review of the literature

Solitary true cysts of the pancreas are extremely rare: to date, only eight cases have been reported in the English literature, four of which had clinical significance. An additional three cases of solitary true cysts of the pancreas are presented. One patient was incidentally found at operation, performed for other disease, to have a cystic lesion in the body of the pancreas; the other two patients experienced abdominal pain and nausea. Abdominal US, CT, and MR showed a unilocular cyst in the body and tail of the pancreas. In both cases, preoperative diagnosis of pancreatic cystic neoplasm was made. Two patients underwent excision of the mass and one distal pancreatectomy. Analysis of the cyst fluid revealed high CA 19-9 levels in two and CA 125 levels in one case. All cysts were lined by cuboidal epithelium, without morphological alterations. Preoperative differential diagnosis with the most common cystic pancreatic lesions (inflammatory or neoplastic) is difficult.