Radiologic Findings of Pancreatic Cystic Neoplasms / 대한내과학회지

With the widespread use of radiologic modalities such as ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI), cystic neoplasms of the pancreas are being increasingly detected; however, developing an accurate characterization and making a differential diagnosis are difficult because of their overlapping morphologic characteristics. Serous cyst adenoma is a common benign neoplasm that is typically observed as a multi-cystic mass or lobulated cyst with or without internal septation. In comparison, mucinous cystic neoplasms appear as smooth cystic tumors with or without internal septation. Finally, intraductal papillary mucinous neoplasms of the pancreas are pleomorphic cystic lesions or clubbed fingerlike tubular structures. These typical imaging findings can help clinicians differentiate cystic neoplasms of the pancreas.

A Case of Primary Paraganglioma that Arose in the Pancreas: the Color Doppler Ultrasonography and Dynamic CT Features

Paragangliomas rarely originate from the pancreas and they are characterized on imaging studies as well-marginated, hypervascular masses with cystic areas. We herein report on a case report of pancreatic paraganglioma in a 57-year-old woman, which was confirmed on pathology. Color Doppler ultrasonography and dynamic CT demonstrated a well-demarcated, extremely hypervascular mass with prominent intratumoral vessels and early contrast filling of the draining veins from the mass. Endoscopic retrograde cholangiopancreatography showed that the main pancreatic duct was displaced and mildly dilated.

Solitary Fibrous Tumor of the Pancreas: Imaging Findings

We report here a case of a pathologically proven solitary fibrous tumor of the pancreas. A 54-year-old man was referred to our hospital for further evaluation of a pancreatic mass that was found incidentally. CT, MR imaging, and endoscopic ultrasonography showed a well-defined, enhancing mass with cystic portions of the pancreas body. MR cholangiopancreatography showed no pancreatic duct dilatation. A solitary fibrous tumor of the pancreas is a very rare lesion.

A Case of Primary Pancreatic T-cell Lymphoma

Primary pancreatic lymphoma is a rare extranodal manifestation of any histopathologic subtype of non-Hodgkin's lymphoma that predominantly involves the pancreas, and it comprises less than 0.5% of all pancreatic malignancies. Histopathologically, most primary pancreatic lymphomas are the B-cell phenotypes, and T-cell lymphomas are extremely rare. We describe here the ultrasonography and computed tomography (CT) findings of a pathologically confirmed pancreatic T-cell lymphoma in a 37-year-old female patient. Ultrasonography showed diffuse pancreatic enlargement and a slightly bulging mass in the head and tail of pancreas that had markedly heterogeneous echogeneity. The lesion abutted onto the adjacent vessels, but there was no evidence of luminal narrowing or obstruction. The CT scan showed diffuse enlargement of the pancreas and the bulging contoured mass at the pancreatic head and tail with inhomogeneous enhancement, including multiple hypodense areas. It also showed the patent peripancreatic vessels and multiple LN enlargements around the pancreas.

A Case of Primary Pancreatic T-cell Lymphoma

Primary pancreatic lymphoma is a rare extranodal manifestation of any histopathologic subtype of non-Hodgkin's lymphoma that predominantly involves the pancreas, and it comprises less than 0.5% of all pancreatic malignancies. Histopathologically, most primary pancreatic lymphomas are the B-cell phenotypes, and T-cell lymphomas are extremely rare. We describe here the ultrasonography and computed tomography (CT) findings of a pathologically confirmed pancreatic T-cell lymphoma in a 37-year-old female patient. Ultrasonography showed diffuse pancreatic enlargement and a slightly bulging mass in the head and tail of pancreas that had markedly heterogeneous echogeneity. The lesion abutted onto the adjacent vessels, but there was no evidence of luminal narrowing or obstruction. The CT scan showed diffuse enlargement of the pancreas and the bulging contoured mass at the pancreatic head and tail with inhomogeneous enhancement, including multiple hypodense areas. It also showed the patent peripancreatic vessels and multiple LN enlargements around the pancreas.

Lymphoepithelial Cyst of the Pancreas: A Case Report

We present a case of lymphoepithelial cyst of the pancreas. The cyst showed moderate echogenicity, mimicking a solid lesion on ultrasonography (US), and had a cystic appearance on computed tomography (CT). This ambivalent finding may be a distinctive feature of lymphoepithelial cysts of the pancreas.

Pancreatic Adenocarcinoma: Dual-Phase Helical CT with Surgical and Histopathologic Correlation

PURPOSE: To determine the accuracy of dual-phase helical CT in assessing the resectability of pancreatic ductal adenocarcinoma, and to correlate the CT findings with the surgical and histopathologic findings. MATERIALS AND METHODS: Thirty patients with pathologically proven cancer of the pancreas underwent arterialand portal- phase helical CT scanning, and in two of these, single-level dynamic CT was performed during celiac and superior mesenteric arteriography. In 17 patients who underwent surgery for potentially resectable cancer of the pancreatic head, tumor resectability was assessed. The CT findings were analyzed and correlated with these of surgery and histopathology. RESULTS: In 13 (76%) of the 17 patients who underwent surgery, tumors were resectable. Their average size was 2.76 cm (arterial phase), 2.30 cm (portal phase), and 2.48 cm (pathologically determined) and the overall accuracy of helical CT for assessing resectability was 87%. In all patients, the central portion of the tumors exhibited hypoattenuation at both phases; the peripheral portion showed hypoattenuation at the arterial phase and iso- (n=10) or hyperattenuation (n=3) at the portal phase. Single-level dynamic CT depicted a persistently ypoattenuating central portion and progressive and prolonged enhancement of the periphery. CT-histopathologic correlation showed that central hypoattenuation indicated the presence of tumor cells, necrosis (n=3) and mucin (n=4), while the peripheral iso- or hyperattenuated areas seen at the portal phase represented fibrosis and inflammatory infiltration. Histopathologic examination revealed tumoral infiltration of peripancreatic fat tissue (n=11) and microvascular invasion of major peripancreatic vessels (n=7). CONCLUSION: The dual-phase helical CT is useful in the determination of resectability in pancreas cancer and CT findings represent well the histopathologic features of pancreas cancer.

Extracorporeal Shock Wave Lithotripsy on Pancreatic Duct Stones in Patients with Chronic Pancreatitis: Evaluation of Therapeutic Results with CT

PURPOSE: To demonstrate by CT scanning the effect of extracorporeal shock wave lithotripsy (ESWL) on pancreatic duct stones in patients with chronic pancreatitis. MATERIALS AND METHODS: Pancreatic duct stones in 11 patients with chronic pancreatitis were subject to ESWL using an electrohydraulic lithotripter. Endoscopic stone removal using a basket had failed in ten patients, and in one, endoscopy was impossible due to a previous Whipple's operation. CT scans obtained before and after ESWL were evaluated by two radiologists: the longest and shortest diameters of the target stone were measured, and according to the degree of fragmentation, determined by comparing the area of the stone before and after ESWL, a grade (1-5) was assigned. In each case, the pre- and post- treatment diameter of the main pancreatic duct, measured at the pancreatic body, was also compared. RESULTS: Disintegration of the target stone was achieved in all patients: grade 1 (over 75% of the area remained, compared with that of the initial stone) was assigned in two patients; grade 2 (51-75% of the original area) in one; grade 3 (26-50%) in four; grade 4 (under 25%) in two; and grade 5 (complete clearance of the target stone) in two. The mean area decreased from 175 mm2 to 69 mm2 after ESWL (p<0.05); a decrease of more than 50% was observed in eight patients (73%). The mean diameter of the main pancreatic duct decreased from 7.36 to 4.81 mm (p<0.05). No severe adverse effects or complications were noted, and all patients showed clinical improvement. Follow-up studies indicated that pancreatic duct stones recurred in three patients. CONCLUSION: ESWL can cause the fragmentation of pancreatic duct stones without significant complications, and should be considered where endoscopic stone removal has failed. CT is a suitable non-invasive and accurate tool for evaluating the therapeutic results of ESWL.

Extramedullary Plasmacytoma of the Pancreas: Imaging Findings: Case Report

Extramedullary plasmacytoma involves organs outside the bone marrow, but involvement of the pancreas is very rare. We present the imaging findings of extramedullary plasmacytoma of the pancreas in a patient with multiple myeloma. Mixed echogenecity was noted at US, and marked enhancement at CT and MR.

US and CT Imaging of Undifferentiated Carcinoma of the Pancreas

We report the case of a 64-year-old female patient with an undifferentiated carcinoma involving the pancreatic head in whom hepatic metastasis and encasement of the portal and superior mesenteric veins had occurred. Ultrasound demonstrated a round well-defined hypoechoic mass with increased color Doppler flow signals at the periphery, while CT revealed a heterogeneously enhanced mass with a less attenuated central portion and rim enhancement of the pancreatic head.

Tuberculous Abscess of the Pancreas Presenting as Obstructive Jaundice: A Case Report

Pancreatic tuberculosis is very rare, though dissemination to the gastrointestinal tract and mesenteric lymph nodes is common. We describe a case of pancreatic tuberculosis presenting as a cystic mass in the pancreatic head, with biliary obstruction, in a patient with miliary pulmonary tuberculosis. Surgery for the curative treatment of jaundice was performed, and the histopathologic findings indicated that a pancreatic abscess with caseous necrosis was present, consistent with tuberculosis.

Inflammatory Pseudotumor of the Pancreas: A Case Report

Inflammatory pseudotumors are tumor-like benign lesions of uncertain pathogenesis and have most commonly been reported in the lungs. In the pancreas they are rare. We describe a case of inflammatory pseudotumor of the pancreas which was seen to be isoattenuating at non-contrast CT, and as a well-defined nodule with homogeneous enhancement in the pancreatic tail at contrast-enhanced CT. After a preoperative diagnosis of islet cell tumor, partial pancreatectomy of the pancreatic tail, with splenectomy, was performed. The gross specimen was a yellowish-white, solid mass and the lesion was histopathologically confirmed as inflammatory pseudotumor with an extensive area of sparse cellular fibrosis and collagen deposition.

CT Findings of Acinar Cell Carcinoma of the Pancreas: Focused on Spiral CT Findings

PURPOSE: To evaluate the CT findings (in particular, those of dual-phase spiral CT) of acinar cell carcinoma of the pancreas. MATERIALS AND METHODS: We retrospectively reviewed the CT findings of pathologically confirmed pancreatic acinar cell carcinoma in seven patients (M:F = 4:3) aged 26 -57 (average,46) years. Serum amylase and lipase were clinically checked, and concomitant subcutaneous nodules or osteolytic bony lesions were evaluated. Contrast-enhanced CT scanning. was performed in seven cases, and in four of these, dual-phase spiral CT scans were also obtained. Tumor size and location, the extent of intratumoral necrosis, calcification, contour, margin, capsule, adjacent organ invasion, lymphadenopathy, hepatic metastasis and enhancement pattern were analyzed. RESULTS: Serum lipase was elevated in three cases, but in all, the serum amylase range was normal. In no case were subcutaneous nodules or osteolytic bony lesions observed. The size of the mass was 5 -18 (mean 8.4 cm), and tumors were located in the tail (n=3), body (n=2) and head (n=1), with one involving both the body and tail. Intratumoral necrosis was noted in six of seven cases and calcification in two. A lobulated contour with capsule was observed in six, and in two there was splenic invasion. In three of four cases in which dual-phase spiral CT was performed, the enhancement pattern was high during the arterial phase and isodense with normal pancreatic parenchyma during the venous phase. In two cases involving spiral CT, multiple hyperattenuated hepatic metastasis was observed during the arterial phase. In three cases in which conventional post-contrast CT was performed, the tumor showed low enhancement. CONCLUSION: Pancreatic acinar cell carcinoma is rare, but if a large, well encapsulated, strongly enhanced pancreatic mass showing central necrosis is observed during the arterial phase of dual-phase spiral CT, and metastatic nodules are also present, pancreatic acinar cell carcinoma should be differentiated from other pancreatic neoplasms.

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

Serous cystadenomas of the pancreas are generally considered to be microcystic adenomas. Typical serous cystadenomas of the pancreas are encapsulated tumors composed of tiny cysts less than 2 cm in size showing sponge-like appearance with a central stellate scar or calcification on the cross-section. It has been recently reported, however, that serous cystadenomas may have macrocystic variants (major cysts more than 2 cm in size) that are radiologically indistinguishable from mucinous cystadenomas of the pancreas. We report the CT and MR imaging findings in a patient with mixed microcystic and macrocystic serous cystadenoma of the pancreas, indicating the histopathologic correlation. The mass was composed of two different types of cyst: multiple, small (2 cm) with peripheral calcification.

Lymphoepithelial Cyst of the Pancreas: A Case Report

Lymphoepithelial cyst of the pancreas is a very rare lesion of unknown etiology. It is difficult, on the basis of radiologic images, to differentiate between lymphoepithelial cyst and pancreatic pseudocyst or other cystic neoplasms, particularly if these are mucinous. We describe the sonographic and CT findings in a case of surgically proven lymphoepithelial cyst of the pancreas.

Pancreatic Cancer: Comparison of Two Series of Dual-phase Helical CT in Detection of Tumor and in Assessing Vascular Invasion

PURPOSE: To compare the clinical utility of two series of dual-phase helical CT scans of the pancreas for tumor detectability and for the evaluation of vascular invasion. MATERIALS AND METHODS:Two series of dual-phase helical CT scans of the pancreas were performed in 49 pa-tients with pancreatic adenocarcinoma proven by pathology (n=21) and by clinical findings (n=28). The first series, in 24 patients, was obtained with a 45-sec (pancreatic phase) and an 80-sec delay (hepatic phase), and for the second series, in 25 patients, the corresponding delay times were 35 and 75 secs. A total of 120 ml non-ionic contrast media was injected of a speed of 3 ml/sec. Tumor conspicuity for each phase was assessed by measuring the attenuation number of the pancreatic mass and of normal pancreas. Enhancement of the celiac axis (CA), superior mesenteric artery (SMA), and superior mesenteric and portal veins was assessed by measuring the attenuation number of each phase. RESULTS: A comparison of the first and second series revealed no statistically significant tumor conspicuity. Enhancement of the celiac axis and superior mesenteric artery was better on scans obtained at 35-sec/75-sec delay (CA 254 HU +/-41, 224 HU +/-43; SMA 259 HU +/-55, 212 HU +/-44; p < .05), as was enhancement of the superior mesenteric and portal veins, but no statistical significance was observed. CONCLUSION: Dual-phase helical CT scans of the pancreas obtained at 35-sec/75-sec and 45-sec/80-sec delay for the pancreatic phase and hepatic phase, respectively, are equal in terms of the detectability of pancreatic ade-nocarcinoma,but for the evaluation of vascular invasion, dual-phase scanning with delays of 35 and 75 sees may be more appropriate.

Radiologic Findings of the Serous Cystadenomas of the Pancreas with Macro cystic or Unilocular Variants: Comparison with the Pathologic Findings

PURPOSE: To evaluate the radiologic findings of the serous cystadenomas of the pancreas with macrocystic or unilocular variants and to compare them with the pathologic findings. MATERIALS AND METHODS: In eight patients(7 females and 1 male ranging in age from 26 to 49 [mean, 37] years) with surgically proven serous cystadenomas, the findings of abdominal CT(n=8), abdominal sonography(US, n=8), endoscopic retrograde pancreatography(ERCP, n=6), endoscopic sonography(EUS, n=3), and MRI(n=1) were evaluated. The location and size of tumors, lobulation, internal septa, solid component, calcification, communication with the pancreatic duct, dilatation of the proximal pancreatic duct, and contrast enhancement on CT were assessed and compared with the pathologic findings. RESULTS: Tumors were located in the head(n=3), body(n=3) and tail(n=2), and their mean size was 4 (range, 1 -8) cm. Abdominal CT scanning revealed well-defined cystic masses composed of macrocyst(s) with calcifica-tion(n=3) and dilatation of the proximal duct (n=2). Three cases showed contrast enhancement of the cystic walls, the pathologic examination of which revealed fibrotic tissues. Four tumeurs were unilocular without septation or lobulation; these features, together with calcification, were depicted more clearly by US and EUS. ERCP revealed no communication between the cysts and pancreatic ducts. Imaging studies showed that macrocystic adenomas were superimposed on mucinous cystadenomas, and unilocular adenomas were indis-tinguishable from pseudocysts. CONCLUSION: Serous cystadenomas of the pancreas with macrocystic or unilocular variants are common in middle-aged women. Features present due to the existence of fibrotic tissues, and which may be reveled by contrast-enhanced CT, include internal septa, calcification, duct dilation, and prominent enhancement of the cystic wall. Serous cystadenoma should be included in the differential diagnosis of macrocystic or unilocular cystic lesions of the pancreas.

Metastatic Tumor of the Pancreas: Helical CT Findings

PURPOSE: To analyze the helical computed tomographic (CT) findings of distant metastatic tumors to the pancreas and to determine the differential points between these and primary pancreatic carcinomas. MATERIALS AND METHODS: We surveyed 22 patients with metastatic tumor of the pancreas, proven on the basis of clinical and pathological findings. Seventeen patients were men, and five and five were women, and their ages ranged between 36 and 83 years. Their primary conditions were lung cancer (n=15), rectal cancer (n=2), melanoma of the foot, chondrosarcoma of the sacrum, cervical cancer, leiomyosarcoma of the uterus, and ex-tragonadal choriocarcinoma of the mediastinum. We retrospectively reviewed the abdominal helical CT findings, analysing the number, location, size and attenuation of masses, as well as secondary change, which included dilatation of the pancreatic and biliary ducts and invasion of peripancreatic tissue or vessels. We also evaluated the differential findings of primary pancreatic cancer. RESULTS: Sixteen patients had a solitary focal mass, while in five, two masses. were present. Among the 22 patients, low-density nodular masses were present in 21; in the other, in whom multiple metastasis from chon-drosarcoma had occurred, there was dense calcification. The size of metastatic masses varied, ranging from 0.6 to 6 cm in diameter. The pancreatic duct proximal to the mass was dilated in ten cases, while the bile duct was dilated in six. The metastatic masses demonstrated no peripancreatic or vascular invasion, though they showed a discrete margin and contour bulging. CONCLUSION: Single metastasis to the pancreas was most common, and metastatic masses had a discrete margin, with contour bulging. There was no peripancreatic or vascular invasion. If the metastasis involved a single low-attenuated mass, however, with pancreatic or biliary dilatation, it was difficult to differentiate this from primary pancreatic cancer.

Multifocal Serous Cystadenoma of the Pancreas: A Case Report

Serous cystadenoma of the pancreas is a benign neoplasm and usually unifocal; multifocal tumors are rare, and to our knowledge, only a few cases have been reported. We describe a case involving two separate serous cystadenomas in the head and body of the pancreas. The patient was a 41-year-old woman with no subjective symptoms. Abdominal ultrasonography performed for the purpose of a routine check-up revealed a septated cystic mass in the body of the pancreas. CBC and blood chemistry revealed no abnormality, but abdominal computed tomography indicated two separate cystic masses with enhanced internal septa in the head and body of the pancreas. Whipple's operation was performed and two serous cystadenomas of the pancreas were diagnosed histopathologically.

Multifocal Serous Cystadenoma of the Pancreas: A Case Report

Serous cystadenoma of the pancreas is a benign neoplasm and usually unifocal; multifocal tumors are rare, and to our knowledge, only a few cases have been reported. We describe a case involving two separate serous cystadenomas in the head and body of the pancreas. The patient was a 41-year-old woman with no subjective symptoms. Abdominal ultrasonography performed for the purpose of a routine check-up revealed a septated cystic mass in the body of the pancreas. CBC and blood chemistry revealed no abnormality, but abdominal computed tomography indicated two separate cystic masses with enhanced internal septa in the head and body of the pancreas. Whipple's operation was performed and two serous cystadenomas of the pancreas were diagnosed histopathologically.