Ursula Pauser

Pancreatic ductal adenocarcinomas with cystic features: neither rare nor uniform

Cystic tumors of the pancreas are uncommon but important because of their diverse pathology and biology. Their wide spectrum also includes cystic variants of otherwise solid tumors, such as cystic endocrine tumors, cystic acinar cell carcinomas and ductal adenocarcinomas with cystic changes. In this study, we screened pancreatic ductal adenocarcinomas and their variants for macrocystic changes and determined the nature of the cysts (neoplastic vs non-neoplastic). Of 483 tumors 38 (8%) had cystic features. The largest group consisted of 24 pancreatic ductal adenocarcinomas showing a large-gland pattern with small cysts whose diameter varied between 0.5 and 1.8 cm. The epithelial lining of these cysts was generally positive for CEA (83%) and/or MUC1 (71%) and MUC5AC (74%). p53 was positive in 57% of the cases. The second group of cystic tumors (8/483) showed degenerative cystic cavities with diameters ranging between 1 and 6 cm. This group consisted of poorly differentiated pancreatic ductal adenocarcinomas, undifferentiated carcinomas with or without osteoclast-like giant cells and one adenosquamous carcinoma. In the third group of cystic tumors there were four pancreatic ductal adenocarcinomas containing tumor-related retention cysts. Their epithelial cells were positive for MUC5AC, but negative for CEA, MUC1 and p53. The fourth group consisted of two pancreatic ductal adenocarcinomas showing closely attached pseudocysts caused by tumor-associated pancreatitis. The results indicate that a considerable number of pancreatic ductal adenocarcinomas and their variants display cystic features and must therefore be considered in the differential diagnosis of cystic neoplasms of the pancreas. Moreover, not all of the cystic structures we observed were neoplastic in nature. They may also represent non-neoplastic changes, such as retention cysts and inflammatory pseudocysts.

Pancreatic solid and cystic hamartoma in adults: characterization of a new tumorous lesion.

Nonneoplastic tumor-like lesions (“pseudotumors”) of the pancreas include cystic and noncystic varieties. We report on a solid and cystic tumor-like lesion of the pancreas that occurred in 2 adult patients. The lesions, located in the head and neck of the gland, respectively, were well demarcated and composed of cystic ductal structures embedded in focally inflamed stromal tissue. In addition, one of the lesions showed irregularly arranged but well-differentiated acini and small intralobular and interlobular ducts embedded in hypocellular, fibrotic tissue. Discrete islets were lacking, but immunohistochemical staining for chromogranin A revealed individual scattered endocrine cells evenly distributed between acinar and ductal cells. The surrounding pancreatic parenchyma did not show significant chronic pancreatitis. After tumor removal, the follow-up of the patients was uneventful. Because of the irregular arrangement of otherwise mature tissue components of the pancreas, the lesions were considered solid and cystic hamartomas. Their pathogenesis is so far unknown.

Cellular hamartoma resembling gastrointestinal stromal tumor: a solid tumor of the pancreas expressing c-kit (CD117)

Solid tumors of the pancreas are usually neoplastic. We report on two adult patients, each with a solid tumor of the pancreas that presented with an unusual histology and seemed to follow a benign course. The tumors, one located in the body and one in the tail, were well demarcated and composed of irregularly arranged but well-differentiated acini and small intralobular and interlobular ducts embedded in predominantly hypocellular fibrotic tissue that contained fascicles of cytologically bland spindle cells. Islets were lacking, but immunohistochemical staining for chromogranin A and insulin revealed individual scattered insulin-producing cells distributed between acinar and ductal cells. The spindle cell component tissue showed coexpression of CD34, c-kit (CD117) and bcl-2. The follow-up (2 and 4 years) of the patients was uneventful. We propose to designate the tumors as ‘cellular hamartoma resembling gastrointestinal stromal tumor.’

[Cystic pancreas tumors and their classification: features old and new].

ZusammenfassungZystische Tumoren and tumorartige Läsionen des Pankreas sind selten. Trotzdem haben sie erhebliche Bedeutung erlangt, da sie mit den neuen radiologischen Verfahren leicht zu entdecken sind und im Gegensatz zum duktalen Adenokarzinom zumeist kurativ reseziert werden können. Durch die zunehmende Resektionsquote hat sich in den letzten Jahrzehnten auch die Kenntnis von den zystischen Pankreastumoren und ihr morphologisches Spektrum enorm erweitert. Bekannte Entitäten wurden besser charakterisiert (solid-pseudopapilläre Neoplasien, intraduktal-papillär-muzinöse Neoplasien) und neue Entitäten beschrieben (seröses oligozystisches Adenom, muzinöse nichtneoplastische Zyste, Azinuszellzystadenom und zystisches Hamartom). Diese Übersicht präsentiert die wichtigsten zystischen Tumoren und Läsionen des Pankreas, stellt eine neue Klassifikation vor und fasst die immunhistochemische Differenzialdiagnose zusammen.AbstractCystic tumors and tumor-like lesions of the pancreas are rare, but have attracted a great deal of attention because they are easily recognized with new imaging methods and, in contrast to ductal adenocarcinoma, they can usually be cured surgically. The increasing resection rate in recent years has also increased our knowledge of cystic pancreatic tumors by conspicuously enlarging their morphological spectrum. Known entities have been better characterized (i.e. solid pseudopapillary neoplasm, intraductal papillary mucinous neoplasm) and new ones described (serous oligocystic adenoma, mucinous non-neoplastic cyst, acinar cell cystadenoma and cystic hamartoma). This review discusses the most important cystic tumors and tumor-like lesions, presents a new classification, and summarizes the immunohistochemical differential diagnosis.

Zystische Pankreastumoren und ihre Klassifikation

ZusammenfassungZystische Tumoren and tumorartige Läsionen des Pankreas sind selten. Trotzdem haben sie erhebliche Bedeutung erlangt, da sie mit den neuen radiologischen Verfahren leicht zu entdecken sind und im Gegensatz zum duktalen Adenokarzinom zumeist kurativ reseziert werden können. Durch die zunehmende Resektionsquote hat sich in den letzten Jahrzehnten auch die Kenntnis von den zystischen Pankreastumoren und ihr morphologisches Spektrum enorm erweitert. Bekannte Entitäten wurden besser charakterisiert (solid-pseudopapilläre Neoplasien, intraduktal-papillär-muzinöse Neoplasien) und neue Entitäten beschrieben (seröses oligozystisches Adenom, muzinöse nichtneoplastische Zyste, Azinuszellzystadenom und zystisches Hamartom). Diese Übersicht präsentiert die wichtigsten zystischen Tumoren und Läsionen des Pankreas, stellt eine neue Klassifikation vor und fasst die immunhistochemische Differenzialdiagnose zusammen.AbstractCystic tumors and tumor-like lesions of the pancreas are rare, but have attracted a great deal of attention because they are easily recognized with new imaging methods and, in contrast to ductal adenocarcinoma, they can usually be cured surgically. The increasing resection rate in recent years has also increased our knowledge of cystic pancreatic tumors by conspicuously enlarging their morphological spectrum. Known entities have been better characterized (i.e. solid pseudopapillary neoplasm, intraductal papillary mucinous neoplasm) and new ones described (serous oligocystic adenoma, mucinous non-neoplastic cyst, acinar cell cystadenoma and cystic hamartoma). This review discusses the most important cystic tumors and tumor-like lesions, presents a new classification, and summarizes the immunohistochemical differential diagnosis.

Solid pseudopapillary neoplasms. Enigmatic entity with female preponderance

ZusammenfassungSolid-pseudopapilläre Neoplasien (SPN) stellen eine morphologisch wie biologisch besondere Tumorentität des Pankreas dar. Es handelt sich um große solitäre Tumoren, die typischerweise bei jungen Frauen auftreten. Histologisch zeigen sie in variabler Zusammensetzung solide, pseudopapilläre und pseudozystische Muster. Die Tumorzellen sind monomorph und ihr Immunprofil ist durch eine Positivität für Vimentin, neuronspezifische Enolase (NSE), β-Catenin und den Progesteronrezeptor charakterisiert. Etwa 90% der Patienten werden durch eine komplette Resektion des Tumors geheilt. Da jedoch in wenigen Fällen Rezidive und Metastasen auftreten können, werden sie als niedrigmaligne eingestuft. Histologisch kann am Primärtumor ein malignes Verhalten nicht vorhergesagt werden. Die wichtigste Differenzialdiagnose ist der neuroendokrine Tumor des Pankreas. Die Ursache und Herkunft der SPN sind unklar.AbstractSolid pseudopapillary neoplasms (SPN) of the pancreas represent a special tumor entity, both morphologically and biologically. They form large solitary tumors that occur predominantly in young women. Histologically, they show solid, pseudopapillary, and pseudocystic patterns. The tumor cells are monomorphous and typically express vimentin, neuron-specific enolase, nuclear β-catenin, and the progesterone receptor. Complete resection cures the tumor in about 90% of the cases. However, because recurrences and even metastases may occur in a small number of cases, SPN are classified as low-grade malignant tumors. Predicting malignancy histologically is not yet possible. The most important differential diagnosis to consider is neuroendocrine tumor of the pancreas. The etiology and pathogenesis of SPN are obscure.

[Mesenchymal tumors of the pancreas. Surprising, but not uncommon].

ZusammenfassungPrimäre mesenchymale Tumoren des Pankreas sind selten. Sie werden unter der Verdachtsdiagnose eines primären soliden oder zystischen Pankreastumors exploriert. Benigne mesenchymale Tumoren umfassen Lymphangiome, Hämangiome, Schwannome, solitäre fibröse Tumoren, Adenomatoidtumoren, den Klarzelltumor und Hamartome. Eine Sonderstellung nehmen die inflammatorischen Pseudotumoren ein. Unter den malignen mesenchymalen Tumoren finden sich Leiomyosarkome, maligne periphere Nervenscheidentumoren (MPNST), Liposarkome, maligne fibröse Histiozytome, Ewing-Sarkome und primitive neuroektodermale Tumoren (PNET). Wichtig ist die differenzialdiagnostische Abgrenzung gegenüber anaplastischen Karzinomen und retroperitonealen mesenchymalen Tumoren mit Infiltration in das Pankreas.AbstractMesenchymal tumors of the pancreas are rare. They are resected because a solid or cystic pancreatic tumor is suspected. Benign mesenchymal tumors comprise lymphangiomas, hemangiomas, schwannomas, solitary fibrous tumors, adenomatoid tumors, clear cell tumors, and hamartomas. Inflammatory pseudotumors are a special case. Malignant mesenchymal tumors include leiomyosarcomas, malignant peripheral nerve sheath tumors (MPNST), liposarcomas, malignant fibrous histiocytomas, Ewing’s sarcomas, and primitive neuroectodermal tumors (PNET). It is important to differentiate these tumors from anaplastic carcinomas and retroperitoneal tumors that infiltrate pancreatic tissue.