Immunohistochemical and molecular analysis of giant cell carcinoma of the pancreas: a report of three cases

Presence of cells in the polyaneuploid cancer cell (PACC) state predicts the risk of recurrence in prostate cancer

BACKGROUND

The nonproliferating polyaneuploid cancer cell (PACC) state is associated with therapeutic resistance in cancer. A subset of cancer cells enters the PACC state by polyploidization and acts as cancer stem cells by undergoing depolyploidization and repopulating the tumor cell population after the therapeutic stress is relieved. Our aim was to systematically assess the presence and importance of this entity in men who underwent radical prostatectomy with curative intent to treat their presumed localized prostate cancer (PCa).

MATERIALS AND METHODS

Men with National Comprehensive Cancer Network intermediate- or high-risk PCa who underwent radical prostatectomy l from 2007 to 2015 and who did not receive neoadjuvant treatment were included. From the cohort of 2159 patients, the analysis focused on a subcohort of 209 patients and 38 cases. Prostate tissue microarrays (TMAs) were prepared from formalin-fixed, paraffin-embedded blocks of the radical prostatectomy specimens. A total of 2807 tissue samples of matched normal/benign and cancer were arrayed in nine TMA blocks. The presence of PACCs and the number of PACCs on each core were noted.

RESULTS

The total number of cells in the PACC state and the total number of cores with PACCs were significantly correlated with increasing Gleason score (p = 0.0004) and increasing Cancer of the Prostate Risk Assessment Postsurgical (CAPRA-S) (p = 0.004), but no other variables. In univariate proportional hazards models of metastasis-free survival, year of surgery, Gleason score (9-10 vs. 7-8), pathology stage, CAPRA-S, total PACCs, and cores positive for PACCs were all statistically significant. The multivariable models with PACCs that gave the best fit included CAPRA-S. Adding either total PACCs or cores positive for PACCs to CAPRA-S both significantly improved model fit compared to CAPRA-S alone.

CONCLUSION

Our findings show that the number of PACCs and the number of cores positive for PACCs are statistically significant prognostic factors for metastasis-free survival, after adjusting for CAPRA-S, in a case-cohort of intermediate- or high-risk men who underwent radical prostatectomy. In addition, despite the small number of men with complete data to evaluate time to metastatic castration-resistant PCa (mCRPC), the total number of PACCs was a statistically significant predictor of mCRPC in univariate analysis and suggested a prognostic effect even after adjusting for CAPRA-S.

Polyploid giant cancer cells and cancer progression

Polyploid giant cancer cells (PGCCs) are an important feature of cellular atypia, the detailed mechanisms of their formation and function remain unclear. PGCCs were previously thought to be derived from repeated mitosis/cytokinesis failure, with no intrinsic ability to proliferate and divide. However, recently, PGCCs have been confirmed to have cancer stem cell (CSC)-like characteristics, and generate progeny cells through asymmetric division, which express epithelial-mesenchymal transition-related markers to promote invasion and migration. The formation of PGCCs can be attributed to multiple stimulating factors, including hypoxia, chemotherapeutic reagents, and radiation, can induce the formation of PGCCs, by regulating the cell cycle and cell fusion-related protein expression. The properties of CSCs suggest that PGCCs can be induced to differentiate into non-tumor cells, and produce erythrocytes composed of embryonic hemoglobin, which have a high affinity for oxygen, and thereby allow PGCCs survival from the severe hypoxia. The number of PGCCs is associated with metastasis, chemoradiotherapy resistance, and recurrence of malignant tumors. Targeting relevant proteins or signaling pathways related with the formation and transdifferentiation of adipose tissue and cartilage in PGCCs may provide new strategies for solid tumor therapy.

Morphologic and Molecular Landscape of Pancreatic Cancer Variants as the Basis of New Therapeutic Strategies for Precision Oncology

To date, pancreatic cancer is still one of the most lethal cancers in the world, mainly due to the lack of early diagnosis and personalized treatment strategies. In this context, the possibility and the opportunity of identifying genetic and molecular biomarkers are crucial to improve the feasibility of precision medicine. In 2019, the World Health Organization classified pancreatic ductal adenocarcinoma cancer (the most common pancreatic tumor type) into eight variants, according to specific histomorphological features. They are: colloid carcinoma, medullary carcinoma, adenosquamous carcinoma, undifferentiated carcinoma, including also rhabdoid carcinoma, undifferentiated carcinoma with osteoclast-like giant cells, hepatoid carcinoma, and signet-ring/poorly cohesive cells carcinoma. Interestingly, despite the very low incidence of these variants, innovative high throughput genomic/transcriptomic techniques allowed the investigation of both somatic and germline mutations in each specific variant, paving the way for their possible classification according also to specific alterations, along with the canonical mutations of pancreatic cancer (KRAS, TP53, CDKN2A, SMAD4). In this review, we aim to report the current evidence about genetic/molecular profiles of pancreatic cancer variants, highlighting their role in therapeutic and clinical impact.

Undifferentiated carcinoma with osteoclast-like giant cells of the pancreas harboring KRAS and BRCA mutations: case report and whole exome sequencing analysis

Background

Undifferentiated carcinoma with osteoclast-like giant cells (UC-OGC) is an extremely uncommon pancreatic neoplasm that comprises less than 1% of all exocrine pancreatic tumors. To date, cases and data from whole-exome sequencing (WES) analysis have been reported by specific studies. We report a case of pancreatic UC-OGC with a literature review, and provide novel insights into the molecular characteristics of this tumor entity.

Case presentation

A 31-year-old male presented with intermittent abdominal pain for several months, and positron emission tomography (PET) showed isolated high metabolic nodules during the pancreatic uncinate process that were likely to be malignant disease. Pathological examination after radical excision revealed UC-OGC associated with poorly differentiated adenocarcinoma at the head of the pancreas. The disease recurred 7.4 months after radical surgery. The KRAS p.G12D (c.35G > A) and somatic BRCA2 p.R2896C (c.8686C > T) mutations were detected by subsequent WES analysis. The patient showed no response to platinum-based systemic chemotherapy, and his condition quickly worsened. He finally died, with an overall survival of 1 year.

Conclusions

As an extremely uncommon tumor entity, UC-OGC is really a unique variant of conventional pancreatic ductal adenocarcinoma due to its similarities, as shown by genomic WES analysis. Clinical examination and molecular analysis by WES could further indicate potential treatment strategies for UC-OGC.

Clinical Characteristics and Overall Survival in Patients with Anaplastic Pancreatic Cancer

Anaplastic pancreatic cancer (APC) is a rare undifferentiated variant of pancreatic ductal adenocarcinoma with poor overall survival (OS). The aim of this study was to evaluate the clinical outcomes of APC compared with differentiated pancreatic ductal adenocarcinoma. We conducted a retrospective review of all patients treated at the Mayo Clinic with pathologically confirmed APC from 1987 to 2011. After matching with control subjects with pancreatic ductal adenocarcinoma, OS was evaluated using Kaplan-Meier estimates and log-rank test. Sixteen patients were identified with APC (56.3% male, median age 57 years). Ten patients underwent exploration of whom eight underwent pancreatectomy. Perioperative morbidity was 60 per cent with no mortality. The median OS was 12.8 months. However, patients with APC who underwent resection had longer OS compared with those who were not resected, 34.1 versus 3.3 months ( P = 0.001). After matching age, sex, tumor stage, and year of operation, the median OS was similar between patients with APC and those with ductal adenocarcinoma treated with pancreatic resection, 44.1 versus 39.9 months, ( P = 0.763). Overall survival for APC is poor; however, when resected, survival is similar to differentiated pancreatic ductal adenocarcinoma.

Polyploid giant cancer cells: Unrecognized actuators of tumorigenesis, metastasis, and resistance

Cancer led to the deaths of more than 9 million people worldwide in 2018, and most of these deaths were due to metastatic tumor burden. While in most cases, we still do not know why cancer is lethal, we know that a total tumor burden of 1 kg-equivalent to one trillion cells-is not compatible with life. While localized disease is curable through surgical removal or radiation, once cancer has spread, it is largely incurable. The inability to cure metastatic cancer lies, at least in part, to the fact that cancer is resistant to all known compounds and anticancer drugs. The source of this resistance remains undefined. In fact, the vast majority of metastatic cancers are resistant to all currently available anticancer therapies, including chemotherapy, hormone therapy, immunotherapy, and systemic radiation. Thus, despite decades-even centuries-of research, metastatic cancer remains lethal and incurable. We present historical and contemporary evidence that the key actuators of this process-of tumorigenesis, metastasis, and therapy resistance-are polyploid giant cancer cells.

Pancreatic undifferentiated carcinoma with osteoclast-like giant cells is genetically similar to, but clinically distinct from, conventional ductal adenocarcinoma

Undifferentiated carcinoma of the pancreas with osteoclast-like giant cells (UCOGC) is currently considered a morphologically and clinically distinct variant of pancreatic ductal adenocarcinoma (PDAC). In this study, we report clinical and pathological features of a series of 22 UCOGCs, including the whole exome sequencing of eight UCOGCs. We observed that 60% of the UCOGCs contained a well-defined epithelial component and that patients with pure UCOGC had a significantly better prognosis than did those with an UCOGC with an associated epithelial neoplasm. The genetic alterations in UCOGC are strikingly similar to those known to drive conventional PDAC, including activating mutations in the oncogene KRAS and inactivating mutations in the tumor suppressor genes CDKN2A, TP53, and SMAD4. These results further support the classification of UCOGC as a PDAC variant and suggest that somatic mutations are not the determinants of the unique phenotype of UCOGC. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Clinical outcomes for anaplastic pancreatic cancer: a population-based study

BACKGROUND

Anaplastic pancreatic cancer (APC) is a rare subtype of pancreatic ductal adenocarcinoma (PDA) that can carry a worse overall survival (OS) when compared with other variants. However, the presence of osteoclast-like giant cells (OCGCs) in APC specimens can predict improved OS. The aim of this study was to evaluate the OS of patients with APC (with and without OCGCs) compared with patients with other subtypes of PDA using a population-based registry.

STUDY DESIGN

We identified all patients in the Surveillance, Epidemiology and End Results (SEER) database with pathologically confirmed APC and PDA diagnosed between 1988 and 2008. Overall survival was evaluated using Kaplan-Meier and Cox proportional hazard regression.

RESULTS

The study cohort included 5,859 (94.3%) patients with PDA and 353 (5.7%) with APC. Overall survival for all patients with APC was significantly worse than for patients with PDA (hazard ratio [HR] = 1.9; 95% CI, 1.7-2.1; p < 0.001); however, in the subgroup of resected patients, APC (n = 81) had similar OS to PDA (n = 3,517) (HR = 0.9; 95% CI, 0.7-1.2; p = 0.37). Patients with APC tumors with OCGCs (n = 11) demonstrated improved OS when compared with all other APC variants without OCGCs (n = 342) (HR = 0.3; 95% CI, 0.1-0.7; p = 0.004), but this survival difference was not observed in the subgroup of resected patients (HR = 0.5; 95% CI, 0.2-1.4; p = 0.18).

CONCLUSIONS

Anaplastic pancreatic cancer is a rare malignancy with poor OS. The diagnosis of APC with OCGCs is predictive of improved OS compared with other patients with APC. This survival benefit, however, is not observed in patients with resected disease.

Pathomorphologic study of undifferentiated carcinoma in seven cases: relationship between tumor and pancreatic duct epithelium

BACKGROUND/PURPOSE

By the time undifferentiated carcinoma is detected, it has formed a large mass, and it is reportedly difficult to pathologically observe its relationship with the pancreatic duct. In this study, we examined the pancreatic ducts of seven patients of surgical samples, and pathomorphologically investigated the relationship between the adenocarcinomatous and sarcomatous components and the pattern of tumor extension. In addition, we evaluated the usefulness of pancreatic juice cytology by comparison with the findings of the main pancreatic duct (MPD).

METHODS

Seven primary undifferentiated carcinomas of the pancreas (from three male and four female patients with a mean age of 59 years) were analyzed. Histopathological evaluation was based on the WHO diagnostic criteria. Pancreatic juice cytology was performed and evaluated in two patients.

RESULTS

All the undifferentiated carcinomas contained adenocarcinomatous and sarcomatous components, and two had a distinct glandular structure. However, we could not pathomorphologically confirm the continuity of the adenomatous with the sarcomatous components in any of the patients. Three undifferentiated carcinomas contained osteoclast-like giant cells. Pathological observation of the tumor and MPD was possible in three of the seven undifferentiated carcinomas. PanIN-3 was observed in the MPD of three patients, suggesting extension into the MPD. In one of these three, the tumor presented intraductal growth in the MPD, and preoperative pancreatic juice cytology revealed atypical cells with osteoclast-like giant cells. In the remaining two, the tumor extraductally compressed the MPD upward.

CONCLUSIONS

Undifferentiated carcinoma showed two patterns of cancer extension: (1) invasion and expansive growth during the sarcomatous transformation of adenocarcinoma, and (2) intraductal extension. In addition, some undifferentiated carcinomas showed extension in the MPD. Of note, postoperative pancreatic juice cytology may be useful for the diagnosis.

Molecular characterization of pancreatic neoplasms

Molecular analyses of neoplasms of the pancreas, coupled with careful histopathologic examination has helped refine the classification of pancreatic neoplasia. A number of molecularly and histologically distinct subtypes of pancreatic neoplasms have been identified and, importantly, many of these subtypes have important clinical implications. For example, most of the solid-pseudopapillary neoplasms harbor mutations in the beta-catenin gene (CTNNB1), and, as a result, most solid-pseudopapillary neoplasms have an abnormal nuclear pattern of labeling with antibodies to the beta-catenin protein. Clinically, patients with a solid-pseudopapillary neoplasm have a much better prognosis than do patients with ductal adenocarcinoma of the pancreas. Therefore, the immunolabeling of a pancreatic biopsy for the beta-catenin protein can help identify patients with low-risk neoplasms. It is clear that the time is now ripe for a new modern classification of neoplasms of the pancreas; a classification that does not abandon gross and microscopic pathology, but which instead integrates molecular findings with gross, microscopic, and clinical findings.

Application of immunohistochemistry to liver and gastrointestinal neoplasms: liver, stomach, colon, and pancreas

CONTEXT

Immunohistochemistry has become an integral component of the practice of pathology. Newer antibodies allow for increasingly precise diagnoses for tumors that previously could not be easily identified. Recently, immunohistochemical evaluations have begun to allow pathologists to actively assist in determining prognosis and even in selecting therapies.

OBJECTIVE

To summarize the usefulness of currently available immunostains for the study of liver and gastrointestinal system neoplasms and to make recommendations for panels of immunostains that can be particularly helpful.

DATA SOURCES

Information has been collected from recent literature as well as from personal experience and practice.

CONCLUSIONS

Many immunostains are now available for the practicing pathologist that allow for increasing accuracy in diagnosis of liver and gastrointestinal tract neoplasms. Panels of immunostains can be used to differentiate between various tumors and also to identify site of origin in the case of a metastatic neoplasm. Immunostains that allow for prognostic determinations and for guidance in the selection of chemotherapeutic agents can also be used by pathologists to assist in the management of patients with malignant tumors affecting the liver and gastrointestinal tract.

Early undifferentiated pancreatic carcinoma with osteoclastlike giant cells: direct evidence for ductal evolution

Undifferentiated (anaplastic) carcinomas of the pancreas are rare. To a variable degree, they may contain osteoclastlike giant cells and are then sometimes referred to as osteoclastlike giant cell tumors. The histogenesis of these tumors has been discussed with great controversy. Thus, as a result from numerous histomorphologic, immunohistochemical, ultrastructural, and molecular examinations, frequently performed as single case studies, it has been concluded that undifferentiated carcinomas and osteoclastlike giant cell tumors of the pancreas originate from epithelial cells, mesenchymal cells, undifferentiated precursor cells, or stem cells. However, to date, early stage tumors have not been described, most likely because of the fact that at the time of diagnosis the tumors have commonly reached advanced stages with large tumor size. In this report, we present the case of an undifferentiated pancreatic carcinoma with osteoclastlike giant cells, which was incidentally detected at a very early stage in a pancreatitis specimen. Our histomorphologic and immunohistochemical findings not only provide evidence for a ductal origin, but for the first time document initial steps in the evolution of these tumors. Therefore, we suggest that the tumor should be considered as an anaplastic variant of pancreatic ductal adenocarcinoma.

Osteoclast-like giant cell tumors of the pancreas and liver

Osteoclast-like giant cell tumors (OGCT) are rare abdominal tumors, which mainly occur in the pancreas. The neoplasms are composed of two distinct cell populations and frequently show an inhomogenous appearance with cystic structures. However, due to the rarity of these tumors, only very limited clinical data are available. Imaging features and sonographic appearance have hardly been characterized. Here we report on two cases of osteoclast-like giant cell tumors, one located within the pancreas, the other within the liver, in which OGCTs are extremely rare. Both patients were investigated by contrast sonography, which demonstrated a complex, partly cystic and strongly vascularized tumor within the head of the pancreas in the first patient and a large, hypervascularized neoplasm with calcifications within the liver in the second patient. The liver OGCT responded well to a combination of carboplatin, etoposide and paclitaxel. With a combination of surgical resection, radiofrequency ablation and chemotherapy, the patient’s survival is currently more than 15 mo, making him the longest survivor with an OGCT of the liver to date.

Pleomorphic Giant Cell Adenocarcinoma of the Prostate

Pleomorphic tumors with giant cells have been described in a variety of primary sites. However, only a few cases have been described among prostatic carcinomas with only 1 on diagnostic biopsy material. Five cases were retrieved from the consultation files of one of the authors. One of the cases was retrieved from the surgical pathology files at our institute. Patient ranged in age from 59 to 76 years (mean=65.8 y). The diagnosis was made on needle biopsy (n=3), urethral biopsy (n=1), transurethral resection (n=1), or radical prostatectomy (n=1). In all cases, giant, bizarre, anaplastic cells were present. In 4 of the cases, marked pleomorphism occupied 5% of the specimen, with 20% and 70% bizarre giant cells in the other 2 cases. In one case, the bizarre cells had atypical mitotic figures, with other cases showing no mitoses in the markedly pleomorphic cells. In addition to the pleomorphic giant cell component, multiple coexistent histologic components were seen including Gleason score 9 conventional prostate cancer (n=6), small cell carcinoma (n=1), squamous carcinoma (n=1), and prominent ductal adenocarcinoma differentiation with intraductal spread (n=1). Immunohistochemically, 4 cases were for negative for prostate-specific antigen in the giant cells, 1 had 5% staining, and the other had 50% positivity in the giant cells. Staining for prostate-specific antigen in the conventional prostate carcinoma component was 1%, 5%, 20%, 50%, 100%, and 100%. The bizarre giant cells were strongly positive for cytokeratins AE1/AE3 and/or Cam 5.2 (n=3). Two cases had a history of conventional prostate cancer 4 years before the giant cell component, 1 treated with Lupron and the other with radiation. Follow-up after diagnosis of the giant cell component: Case 1: dead in 1 year of disease; Case 2: progressive metastases in 2 years; Case 3: alive at 1 year with disease; Case 4: large perineal recurrence after brachytherapy at 3 years; Case 5: radical prostatectomy with extraprostatic extension and seminal vesicle invasion; and Case 6: alive at 3 months, free of disease. Conventional prostate cancer, even when very high grade, typically consists of cells with relatively uniform nuclei. Our study expands the histology described in prostate cancer to include in very rare cases with prominent pleomorphism and bizarre giant cells. This giant cell component heralds a particularly aggressive clinical outcome.

Immunohistochemical and genetic analysis of osteoclastic giant cell tumor of the pancreas

Clinical, histopathologic, immunohistochemical, and genetic analyses of 2 osteoclastic giant cell tumors of the pancreas are presented. The neoplasms were composed of osteoclastic giant cells and pleomorphic cells (PCs). The tissue-specific markers gave evidence of mesenchymal nature of the osteoclastic giant cells, as well as other components of the tumor, and lacked any signs of epithelial differentiation in both patients. The nonepithelial nature of both components in the osteoclastic giant cell tumors presented may be associated with a better prognosis, which corresponds to the previous reports of similar neoplasms. A positive immunoreactivity to neuron-specific enolase was recorded in patient 2. The presence of CD68 in osteoclastic giant cells proved their histiocytic nature. Both components of the tumors showed a negative immunoreactivity to desmin and only a scattered reactivity to smooth muscle cell actin, typical markers of myofibroblastic differentiation. Mutation analysis of the tumor revealed the wild state of both p53 and K-ras oncogenes in both patients. A positive immunoreactivity for p53 in PCs of both osteoclastic giant cell tumors was recorded, whereas osteoclastic giant cells did not express this protein. The expression of p21 was recorded in osteoclastic giant cells in patient 1. The absence of Ki-67 in the osteoclastic giant cells and its expression in PCs gave evidence of a different proliferation rate of both cell populations. Different tissue-specific markers, a different proliferation rate, and a different state of oncogene activation in the osteoclastic giant cell tumors contribute to the idea that the tumor derives from a pluripotent cell that may differentiate into an array of phenotypes.

Expression of novel markers of pancreatic ductal adenocarcinoma in pancreatic nonductal neoplasms: additional evidence of different genetic pathways

Solid pseudopapillary tumor, pancreatoblastoma, undifferentiated carcinoma with osteoclastic-like giant cells, and acinar cell carcinomas are rare pancreatic nonductal neoplasms. Compared to the significant advances in our understanding of the pathogenesis of pancreatic ductal adenocarcinomas in the last decades, the molecular mechanisms underlying pancreatic nonductal neoplasms are poorly understood. In order to elucidate their molecular pathogenesis, we constructed tissue microarrays to study the expression of some novel pancreatic ductal adenocarcinoma-associated tumor markers in these nonductal pancreatic neoplasms. We analyzed nine markers including tumor suppressor gene (14-3-3 sigma), proliferation marker (topoisomerase II alpha), epithelial markers (prostate stem cell antigen, mesothelin and cytokeratin 19), stromal markers (fascin, hsp47 and fibronectin), and gamma-synuclein whose function is not delineated. In addition, we included tumor suppressor gene DPC4 and oncogene Beta-catenin to further confirm their expression in pancreatic nonductal tumors. Our results showed that in contrast to pancreatic ductal adenocarcinomas that show loss of Dpc4 protein in 55% of cases, loss of Dpc4 expression is absent in pancreatic nonductal neoplasms. Expression of 14-3-3 sigma is frequently seen in both pancreatic nonductal neoplasms (25-100%) and ductal adenocarcinomas (89%). Aberrant nuclear expression of beta-catenin is common in pancreatic nonductal neoplasms, specifically in solid pseudopapillary tumors (88%) and pancreatoblastomas (100%) but is rarely seen in pancreatic ductal adenocarcinomas (<5%). Expression of topoisomerase II alpha is not seen in solid pseudopapillary tumors and undifferentiated carcinomas with osteoclastic-like giant cells but is focally seen in pancreatoblastomas (50%) and acinar cell carcinomas (85%). Expression of PSCA and mesothelin was observed in pancreatic nonductal neoplasms but their expression was seen less frequently (0-50%) and weaker than that in pancreatic ductal adenocarcinomas (60-100%). CK19, a marker of pancreatic ductal adenocarcinomas, is not expressed in pancreatic nonductal neoplasms. Expression of gamma-synuclein as well as stromal markers (fascin, hsp47 and fibronectin) is frequently seen in both. Our findings indicate pancreatic nonductal neoplasms have distinctive patterns of protein expression relative to pancreatic ductal adenocarcinomas and suggest that pancreatic nonductal neoplasms have different genetic pathways from the more common pancreatic ductal adenocarcinomas.

A case of osteoclast-like giant cell tumor of the pancreas with ductal adenocarcinoma: histopathological, immunohistochemical, ultrastructural and molecular biological studies

Osteoclast-like giant cell tumor of the pancreas is a very rare neoplasm, of which the histiogenesis remains controversial. A 63-yr-old woman was hospitalized for evaluation of epigastric pain. An abdominal computerized tomography revealed the presence of a large cystic mass, arising from the tail of pancreas. A distal pancreatectomy with splenectomy was performed. Histologically, the tumor was composed of mononuclear stromal cells intermingled with osteclast-like giant cells. In addition, there was a small area of moderately to well differentiated ductal adenocarcinoma. The final pathologic diagnosis was osteoclast-like giant cell tumor of the pancreas with ductal adenocarcinoma. Here, we describe the histopathological, immunohistochemical, ultrastructural and molecular biological findings of this tumor with review of the literature pertaining to this condition.

Pleomorphic Giant Cell Carcinoma of the Prostate

We report the clinical and pathologic features of 2 cases of pleomorphic giant cell carcinoma of the prostate. One case was found at autopsy in a 77-year-old man and was composed of high-grade prostatic adenocarcinoma with prominent anaplastic giant cells. The patient presented with metastases to multiple retroperitoneal lymph nodes, liver, and lumbar vertebrae. The second case occurred in a 45-year-old man who underwent transurethral resection of the prostate and was found to have high-grade prostatic adenocarcinoma with an extensive anaplastic giant cell component. The patient presented with distant metastases and died within 9 months. Both regular adenocarcinoma and anaplastic giant tumor cells displayed cytoplasmic immunoreactivity for prostate-specific antigen, prostatic acid phosphatase, and keratin AE1/AE3; in one case, scattered cells were also positive for chromogranin and epithelial membrane antigen. Pleomorphic giant cell carcinoma is a rare variant of prostatic adenocarcinoma with a poor prognosis that should be considered in the differential diagnosis of prostatic pleomorphic tumors.

Osteoclast-like giant cell tumor in mucinous cystadenocarcinoma of the pancreas: an immunohistochemical and molecular analysis

Osteoclast-like giant cell tumors (OLGT) are rare neoplasms of the pancreas and mostly associated with ductal adenocarcinomas. In this report, we present the rare case of OLGT associated with mucinous cystadenocarcinoma (MCC). We investigated the expression profile of both tumors by methods of molecular biology and immunohistochemistry. The panel of markers included osteopontin, her2/neu, mismatch repair genes, K-ras, p53, E-cadherin, VEGF-C, and podoplanin. Osteopontin was expressed by the osteoclast-like giant cells but not by the mononuclear tumor cells of the OLGT. We detected an amplification and overexpression of her2/neu in the MCC but not in the OLGT. Although we observed an immunohistochemical expression of hMSH2 and hMLH1 in the OLGT, we were not able to confirm this result by western blot analysis. We also did not find any microsatellite instability (D2S123, BAT26). While mutation of K-ras codon 12 was found in both tumor components, there was wild-type DNA of p53. E-cadherin was expressed in MCC but not in OLGT. VEGF-C was only positive in osteoclast-like giant cells and some of the mononuclear cells of OLGT. The vessel-rich stroma of OLGT did not present any podoplanin-positive lymphatic vessel. The observation of our case and others in the published literature may indicate separating OLGT with undifferentiated carcinoma from OLGT with MCC for the better clinical outcome of the latter.

A case of osteoclast-type giant cell tumor of the pancreas with high-frequency microsatellite instability

It has been reported that osteoclast-type giant cell tumor of the pancreas (OGTP) is rare, with a frequency of only 0.2% of the total reported pancreatic carcinomas. We report herein a rare case of OGTP in a 57-year-old Japanese man. Preoperative examinations showed a solid and cystic tumor, measuring 20 x 15 cm at the pancreas body. The resected specimen was a solid tumor with a giant cyst containing bloody contents. The tumor was composed of a proliferation of mononuclear cells admixed with osteoclast-type giant cells. The tumor cells were immunoreactive for vimentin, alpha1-antitrypsin, and EMA but not for CEA and cytokeratin. These findings indicated that this case was a malignant OGTP. The tumor cells showed microsatellite instability with high frequency (MSI-H). The present patient is alive 3 years after the operation, while OGTP has been reported to have a poor outcome. It has been reported that pancreatic carcinomas with MSI-H status have a favorable outcome. MSI-H might be one of the predictive markers for the long survival in OGTP.

The pathology of ductal-type pancreatic carcinomas and pancreatic intraepithelial neoplasia: insights for clinicians

The phenotypic classification of pancreatic neoplasms is based on their cellular lineage. Thus, tumors with a ductal, acinar, and endocrine phenotype can be distinguished. Most pancreatic neoplasms show a ductal phenotype and can be classified as ductal adenocarcinomas. Less common tumors with a ductal phenotype are the variants of ductal adenocarcinoma, intraductal papillary mucinous neoplasm (including colloid carcinoma), mucinous cystic neoplasm, medullary carcinoma, and other rare tumors. Ductal adenocarcinomas most likely develop from ductal proliferative lesions arising in the pancreatic duct system. A recently adopted classification system for these lesions distinguishes between three grades of pancreatic intraepithelial neoplasia (PanIN). Molecular studies have revealed that PanIN-2 and PanIN-3 lesions represent a distinct step toward invasive carcinoma.

Lobular carcinoma of the breast metastatic to the epidural space: a potential mimic of giant cell bone tumor

We report the case of a 64-year-old woman with a spinal epidural mass. Tissue from a decompression laminectomy disclosed a tumor with numerous osteoclast-like giant cells separated by small, moderately atypical tumor cells. The osteoclast-like giant cells were immunoreactive for vimentin, but negative for epithelial membrane antigen and broad-pectrum cytokeratin. Subsequent breast biopsy revealed a lobular carcinoma of classic type without osteoclast-like giant cells. This is the first reported case in which metastatic breast carcinoma was accompanied by these giant cells but the giant cells were not present at the primary tumor site.

Osteoclastic giant cell tumor of the pancreas: case report and literature review

An unusual case of a 40-year-old woman seeking treatment for a 10-cm cystic neoplasm of the pancreas is described. Imaging revealed a large proteinaceous, fluid-filled cyst with a mural nodule. Laparotomy was successful with en bloc resection. Pathologic examination revealed a neoplastic mucinous epithelial tumor with an abundance of multinucleated tumor giant cells. This presentation is consistent with literature reports of an osteoclastic-type giant-cell tumor of the pancreas. The natural history, pathologic evaluation, and clinical implications of this rare neoplasm are discussed with reference to published reports.

In vitro induction of giant cell tumors from cultured hamster islets treated with N-Nitrosobis(2-Oxopropyl)amine

Giant cell carcinoma of the pancreas is a rare tumor. Its histogenesis is still controversial. In a Syrian hamster pancreatic cancer model, tumors similar to human giant cell carcinomas have been induced at an extremely low rate of incidence and after the use of high doses of pancreatic carcinogens. Thus far no tumors of giant cell type have been induced by the in vitro treatment of hamster pancreatic ductal cells with the potent pancreatic carcinogen N-nitrosobis(2-oxopropyl)amine (BOP). In the present study we report the induction of giant cell carcinoma from hamster islets treated with BOP in vitro. The results suggest that in hamsters some component of islet cells, probably stem cells, are the origin of giant cell carcinoma.