Osteoclast-type giant cell tumour of the pancreas

Undifferentiated Carcinoma of Pancreas with Osteoclast-Like Giant Cells: One Center’s Experience of 13 Cases and Characteristic Pre-Operative Images

Background

Methods

Results

Conclusion

Clinical Characteristics and Prognosis of Osteoclast-like Giant Cell Tumors of the Pancreas Compared with Pancreatic Adenocarcinomas: A Population-Based Study

Background

The incidence of osteoclast-like giant cell tumor of the pancreas (OGTP) is very low, and relatively little OGTP clinical data is available. The present study, therefore, sought to conduct a more comprehensive analysis of the clinical characteristics and prognosis of OGTP.

Material/Methods

A large population-based cohort analysis was conducted using the Surveillance, Epidemiology and End Results (SEER) registry. We conducted a systematic assessment of the demographic and clinical characteristics of these patients, in addition to assessing available prognostic and therapeutic data corresponding to their disease. We further compared overall survival (OS) in these OGTP and pancreatic adenocarcinoma (PA) patient cohorts, adjusting for sex, grade, stage, and surgical treatment by propensity score matching (PSM).

Results

We included a total of 47 OGTP patients and 73 150 PA patients in the present analysis. The mean ages of PA and OGTP diagnosis were 68.0 and 62.8 years, respectively. Compared with PA patients, OGTP patients were more likely to be female (70.2% versus 48.7%, P<0.01), to have early-stage disease, to have lower rates of lymph node metastasis (17.0% versus 28.8%, P<0.01) and distant metastasis (17.0% versus 45.1%, P<0.01), and to have higher rates of tumor resection (70.2% versus 15.4%, P<0.01). OGTP patients also had a significantly longer median OS than did PA patients (13 months versus 6 months; hazard ratio [HR] 0.55, 95% confidence interval [CI] 0.37–0.57, P<0.0001). No significant differences in tumor site preferences were detected. Our findings also suggested that being female, having early-stage disease, and undergoing surgical resection may be associated with a more favorable prognosis in patients with OGTP.

Conclusions

OGTP patients had distinctive clinical characteristics and a better prognosis compared with PA patients. Understanding these differences will help clinicians accurately recognize these diseases. Radical resection was beneficial to the survival of OGTP patients.

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.

How to reconstruct a Michels type 9 hepatic artery using the inverted splenic artery technique

This case aims to report a video of a pancreaticoduodenectomy that required both portal vein and Michels type 9 hepatic artery reconstruction using the inverted splenic artery technique in a patient with a rare condition.

Primary osteoclast-like giant cell tumor of parotid gland: A rare extraskeletal presentation with diagnostic challenges

Primary osteoclast-like giant cell tumor (OC-GCT) has been rarely described in extraskeletal sites. The diagnosis primarily hinges on the detection of giant cells. However, these giant cells are also seen in many giant cell lesions, thus creating diagnostic confusion and dilemma. Here, we describe a rare case of a 24-year-old male with primary extraskeletal, OC-GCT presenting as a swelling in the right parotid region and highlight its cytological, histological and immunohistochemical characteristics with diagnostic challenges.

A Non-epithelial Pseudosarcomatous Mural Nodule in a Mucinous Cystic Neoplasm of the Pancreas

A mucinous cystic neoplasm of indeterminate malignant potential was found to have a well-circumscribed, 3.1 cm pseudosarcomatous mural nodule, similar to those previously described in the ovary. The nodule contained reactive giant cells and intermediate to large-sized tumor cells with bizarre mitotic figures and nuclear atypia. The tumor cells were found to be of non-epithelial origin, based on multiple negative stains for cytokeratins and ultrastructural demonstration of osteoclastic and osteoblastic differentiation and absent desmosomes. This case report is the only description of a pseudosarcomatous mural nodule in a mucinous cystic neoplasm with non-epithelial origins.

An indeterminate mucin-producing cystic neoplasm containing an undifferentiated carcinoma with osteoclast-like giant cells: a case report of a rare association of pancreatic tumors

Background

Only few case reports of mucinous cystic pancreatic neoplasm containing an undifferentiated carcinoma with osteoclast-like giant cells have been described in the literature. In the majority of cases this unusual association of tumors seems related to a favorable outcome. We present the second case of an indeterminate mucin-producting cystic neoplasm containing an area of carcinoma with osteoclast-like giant cells. The specific features of the two histotypes and the rapid course of the disease make our clinical case remarkable.

Case presentation

A 68 year old female came to our attention for a pancreatic macrocystic mass detected with ultrasonography. Her past medical history was silent. The patient reported upper abdominal discomfort for two months; nausea, vomiting or weight loss were not reported. Physical examination revealed a palpable mass in the epigastrium; scleral icterus was absent. Cross-sectional imaging showed a complex mass of the neck and body of the pancreas, characterized by multiple large cystic spaces separated by thick septa and an area of solid tissue located in the caudal portion of the lesion. The patient underwent total pancreatectomy with splenectomy. Pathological examination revealed a mucinous cystic neoplasm with a component of an undifferentiated carcinoma with osteoclast-like giant cells. Because of the absence of ovarian-type stroma, the lesion was classified as an indeterminate mucin-producing cystic neoplasm of the pancreas. The immunohistochemical studies evidenced no reactivity of osteclast-like giant cells to epithelial markers but showed a positive reactivity to histiocytic markers. Numerous pleomorphic giant cells with an immunohistochemical sarcomatoid profile were present in the undifferentiated carcinoma with osteoclast-like giant cells. A rapid tumor progression was observed: liver metastases were detected after 4 months. The patient received adjuvant chemotherapy (Gemcitabine) but expired 10 months after surgery.

Conclusion

Our case confirms that the presence of a solid area in a cystic pancreatic tumor at cross-sectional imaging should raise a suspicion of malignant transformation. The lack of ovarian-type stroma in a pancreatic mucinous cystic neoplasm and the presence of pleomorphic giant cells in an undifferentiated carcinoma with osteoclast-like giant cells could be a marker of a poor prognosis.

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.

A male case of an undifferentiated carcinoma with osteoclast-like giant cells originating in an indeterminate mucin-producing cystic neoplasm of the pancreas. A case report and review of the literature

We report a rare male case of an undifferentiated carcinoma with osteoclast-like giant cells originating in an indeterminate mucin-producing cystic neoplasm of the pancreas. A 59-year-old Japanese man with diabetes visited our hospital, complaining of fullness in the upper abdomen. A laboratory analysis revealed anemia (Hemoglobin; 9.7 g/dl) and elevated C-reactive protein (3.01 mg/dl). Carbohydrate antigen 19-9 was 274 U/ml and Carcinoembryonic antigen was 29.6 ng/ml. A computed tomography scan of the abdomen revealed a 14-cm cystic mass in the upper left quadrant of the abdomen that appeared to originate from the pancreatic tail. The patient underwent distal pancreatectomy/splenectomy/total gastrectomy/cholecystectomy. The mass consisted of a multilocular cystic lesion. Microscopically, the cyst was lined by cuboidal or columnar epithelium, including mucinous epithelium. Sarcomatous mononuclear cells and multinucleated osteoclast-like giant cells were found in the stroma. Ovarian-type stroma was not seen. We made a diagnosis of osteoclast-like giant cell tumor originating in an indeterminate mucin-producing cystic neoplasm of the pancreas. All surgical margins were negative, however, two peripancreatic lymph nodes were positive. The patient recovered uneventfully. Two months after the operation, multiple metastases occurred in the liver. He died 4 months after the operation.

Osteoclastic and pleomorphic giant cell tumors of the pancreas: A review of clinical, endoscopic, and pathologic features

Giant cell tumors of the pancreas come in three varieties-osteoclastic, pleomorphic, and mixed histology. These tumors have distinctive endoscopic, clinical, and cytological features. Giant cell tumors have a controversial histogenesis, with some authors favoring an epithelial origin and others favoring a mesenchymal origin. The true origin of these lesions remains unclear at this time. These are also very rare tumors but proper identification and differentiation from more common pancreatic adenocarcinoma is important. The risk factors of these tumors and the prognosis may be different from those associated with standard pancreatic adenocarcinoma. Recognition of these differences can significantly affect patient care. These lesions have a unique appearance when imaged with endoscopic ultrasound (EUS), and these lesions can be diagnosed via EUS guided Fine Needle Aspiration (FNA). This manuscript will review the endoscopic, clinical, and pathologic features of these tumors.

Osteoclastic and pleomorphic giant cell tumors of the pancreas diagnosed via EUS-guided FNA: unique clinical, endoscopic, and pathologic findings in a series of 5 patients

INTRODUCTION

Osteoclastic and pleomorphic giant cell tumors of the pancreas are rare entities that have been typically described only in single case reports. We report on our experience with a series of 5 patients with pancreatic giant cell tumors seen at our institution.

METHODS

This was a retrospective study involving a search of the study institution's medical records from 2001 to 2007 for patients diagnosed with giant cell-containing neoplasms of the pancreas.

RESULTS

Five patients (2 women, 3 men) were identified. Age range was 59 to 81 years, with a mean of 70.2 years. None were current or former smokers. None had a history of alcohol abuse or preexisting pancreatitis of any kind. On EUS, tumors tended to be large, with a mean diameter of 47 mm (range 20-70 mm). All tumors had a heterogeneous echotexture and a distinct appearance when compared with the typical appearance of adenocarcinoma when viewed via EUS. The diagnosis of giant cell tumor of the pancreas, as well as the subtype, was made via EUS-guided FNA of the pancreatic lesion. Patients with pleomorphic giant cell tumors of the pancreas had a poor clinical course with a rapid decline, whereas those with mixed or osteoclastic giant cell tumors tended to have a better outcome, with a greater long-term survival. One patient is still alive more than 18 months after diagnosis.

LIMITATION

Retrospective study.

CONCLUSIONS

Giant cell tumors of the pancreas have unique clinical, endoscopic, and cytologic features. The risk factors for these lesions may be different from those associated with pancreatic adenocarcinoma. Some giant cell tumor subtypes may carry a more favorable prognosis than pancreatic adenocarcinoma, and awareness and recognition of these differences can affect patient care.

Giant-cell containing neoplasms of the pancreas: an aspiration cytology study

Giant-cell containing neoplasms of the pancreas are rare with few reports documenting their cytologic appearance. Giant-cell containing neoplasms of the pancreas have been divided into two subtypes corresponding to the osteoclastic giant-cell tumor of the pancreas and the pleomorphic giant-cell carcinoma of the pancreas. Despite the better prognosis reported in some series for osteoclastic giant-cell tumors, the most recent edition of the World Health Organization classification lumps the two entities into a single category designated as undifferentiated carcinoma with osteoclast-like giant cells. Smears obtained from osteoclastic giant-cell tumors show numerous giant-cells with clustered overlapping, bland appearing nuclei containing prominent nucleoli consistent with an osteoclast-type multinucleated giant-cell. These neoplasms contain a second population of mononuclear cells showing more marked nuclear atypia. Pleomorphic giant-cell carcinomas are characterized by anaplastic giant-cells displaying marked nuclear pleomorphism. The mononuclear component is also pleomorphic with markedly atypical epithelioid and spindle shaped cells. In three reported cases, a tumor contained a mixture of the two cell patterns. Thus, undifferentiated carcinoma with osteoclast-like giant cells and pleomorphic giant cell carcinoma may represent a morphologic spectrum with pure osteoclast-like giant-cell tumors at one end and pleomorphic giant-cell carcinoma at the other. Fine-needle aspiration specimens from pure osteoclast-like giant-cell tumors will contain a population of bland multinucleated osteoclastic-like giant-cells that differ markedly from the anaplastic giant-cells of pleomorphic giant-cell carcinoma. The difference in the appearance of the giant-cells aids in distinction of the two neoplasms. When in pure form, the two neoplasms may follow different clinical courses.

[Osteoclastic giant cell tumour of the pancreas]

Osteoclast giant cell tumours are bone tumours that occur in adults, and that are considered benign by WHO but locally aggressive. Strictly identical tumours are described in the pancreas, without simultaneous bone localization. We report the case of a 62-year woman with an osteoclast giant cell tumour of the distal pancreas, without any epithelial component, which was diagnosed after pancreatic resection and with no signs of recurrence after a 24-month follow-up. These pancreatic tumours are rare, with a very poor prognosis, an unclear histogenesis; they are often confused with pleomorphic or undifferentiated pancreatic carcinomas including a component of osteoclast giant cell. These osteoclast giant cell tumours of the pancreas usually present as large cystic tumours. In certain cases, complete resection can result in long-term survival.

Osteoclastoma-like Giant Cell Tumor of the Lung

The main components of an unusual form of lung tumor were osteoclast-like multinucleated giant cells and mononuclear stromal cells. Besides, scattered islands of moderately differentiated squamous cells also appeared. Both the mononuclear and the osteoclast-like giant cells reacted with antibodies against CD68 and vimentin, but did not react with antibodies against cytokeratin, EMA and CEA, or lysozyme and a-1-antitrypsin. The p53 and PCNA antigens were positive only in mononuclear cells and not the osteoclast-like giant cells, suggesting that mononuclear cells represent proliferating elements with histiocytic differentiation while osteoclast-like giant cells are stromal, presumably reactive components of the tumor.

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.

K-ras oncogene mutations in osteoclast-like giant cell tumors of the pancreas and liver: genetic evidence to support origin from the duct epithelium

Osteoclast-like giant cell tumors (OCGTs) of the pancreas and liver are enigmatic tumors. Despite their striking morphologic resemblance to certain mesenchymal tumors of bone and tendon sheath, it has been suggested that these tumors may, in fact, arise from epithelial precursors. It is also unclear whether the osteoclast-like giant cells in OCGTs are neoplastic or nonneoplastic. We identified OCGTs of the pancreas and liver that were associated with atypical intraductal epithelial proliferations or mucinous cystic neoplasms. To determine the relationship between the noninvasive epithelial proliferations and the infiltrating OCGTs, each individual component was analyzed for mutations at codon 12 of the K-ras oncogene. Four of the five-duct epithelial lesions harbored activating mutations of the K-ras oncogene. In each case, the same K-ras mutation was also present in the mononuclear cells from the paired OCGT. Moreover, these same mutations were detected when the osteoclast-like giant cells were individually microdissected and analyzed. A panel of immunohistochemical stains was performed, and the osteoclast-like giant cells demonstrated macrophage differentiation. These cells were consistently reactive for the monocyte/macrophage marker KP1, but showed absent staining for a panel of epithelial markers. The infiltrating mononuclear cells lacked strong staining for epithelial markers and monocyte/macrophage markers. These findings suggest that OCGTs of the pancreas and liver are undifferentiated carcinomas that arise directly from intraductal epithelial precursors. The finding of K-ras mutations in the osteoclast-like giant cells may reflect their propensity to phagocytize tumor cells.

Undifferentiated carcinoma with osteoclast-like giant cells of the pancreas and periampullary region

BACKGROUND

Undifferentiated carcinomas with osteoclast-like giant cells are rare pancreatic and periampulary neoplasms that morphologically mimic giant cell tumor of bone. Despite numerous publications based primarily on single case reports, the terminology, histogenesis, and biologic behavior of these tumors remain controversial.

METHODS

The authors studied one periampullary and nine pancreatic neoplasms of this type. Immunohistochemistry was performed on nine of the cases and clinical follow-up data was obtained in eight.

RESULTS

The neoplasms were large (average 9 cm), partially or completely multicystic, and hemorrhagic. Histologically, they were composed predominantly of ovoid or spindle-shaped bland mononuclear cells and evenly spaced osteoclast-like giant cells. However, three neoplasms had foci in which the nuclear pleomorphism of the mononuclear cells approached that observed in anaplastic spindle and giant cell carcinomas. Other histologic features included phagocytosis of the mononuclear cells by the osteoclast-like giant cells (in 7 of 10 cases), osteoid or bone formation (in 3 of 10 cases), and chondroid differentiation (in 1 of 10 cases). Four neoplasms had foci of conventional adenocarcinoma and two arose in preexisting mucinous cystic neoplasms of the pancreas. The mononuclear cells were positive for epithelial markers in six of nine tumors tested (cytokeratins AE-1, AE-3, Cam 5.2, and/or epithelial membrane antigen). They were negative for the histiocytic markers (CD-68, lysozyme) in all nine cases tested. In contrast, the osteoclast-like giant cells were positive for CD-68 in all nine cases, positive for lysozyme in four cases, and negative for cytokeratins (AE-1, AE-3, and Cam 5.2) in all nine cases. p53 stained the mononuclear tumor cells in three cases and MIB-1 stained the mononuclear tumor cells in four cases, but the osteoclast-like giant cells did not stain with either antibody in all nine cases tested. Most of the patients died of disease within 1 year of diagnosis; only 1 patient was alive and disease free 14 years after surgical excision.

CONCLUSIONS

The association of these tumors with conventional adenocarcinoma or mucinous cystic neoplasms, the histologic features, and the immunohistochemical profile supports an epithelial phenotype for the mononuclear cells and a reactive histiocytic lineage for the nonneoplastic osteoclast-like giant cells. These neoplasms, which are better classified as undifferentiated carcinomas, follow an aggressive clinical course; most patients die of disease within 1 year.

Mixed pleomorphic-osteoclast-like tumor of the pancreas. Light microscopical, immunohistochemical, and molecular biological studies

The morphological, immunohistochemical, and molecular biological features of a case of giant cell tumor of the pancreas are described. This neoplasm showed mononuclear and multinucleated tumor giant cells as well as numerous osteoclast-like cells with multiple foci of osteoid-osseous metaplasia. The pleomorphic and osteoclastic giant cells displayed extensive homologies in their immunohistochemical profiles. Neither the pleomorphic nor osteoclast-like portion of the tumor showed neither c-Ki-ras nor p53 mutation and did not express the mutated p53 protein. The results suggest that the pleomorphic and osteoclast-like components are histogenetically related and that this rare neoplasm originates from a precursor cell capable of differentiating along divergent cell type.

An unusual epithelial pleomorphic giant cell tumour of the pancreas with osteoclast-type cells

A case of giant cell tumour of the pancreas with a mixture of pleomorphic giant cells and osteoclast-like cells is described. This association is rare and its histogenesis has been debated. The presence of a small differentiated adenocarcinomatous area at the periphery of the tumour indicates an epithelial origin. Moreover, some pleomorphic cells were positive for keratin (KL1). The osteoclast-like cells strongly expressed CD68 (a marker of histiomonocytic lineage) and did not show proliferative activity. They probably correspond to an unusual reaction of the stroma. Their clinical importance in this type of tumour remains unknown.

Case report: malignant giant cell tumour of the pancreas presenting as a large pancreatic cyst

Carcinoma of the pancreas is a common tumour. Histologically, the majority are adenocarcinomas of duct origin. Carcinomas of the pancreas containing giant cells are uncommon and those containing osteoclast-type tumour cells are very rare. We report a case of malignant giant cell tumour presenting as an extremely large, thin walled haemorrhagic cyst of the pancreas. This tumour is most unusual in that the wall is composed of multiple highly pleomorphic malignant-looking multinucleated giant cells as well as numerous osteoclast-like giant cells in a stroma of small spindle shaped mononuclear cells.

A case of AFP-positive pancreas papillary carcinoma suggestive of a primitive endoderm phenotype

In a 70 year old woman with a tumor in the head of the pancreas, the lesion was predominantly composed of papillary adenocarcinoma protruding into the main pancreatic duct, with periductal invasion. The major portion of the adenocarcinoma was intraductal and was composed of tall columnar epithelial cells with pseudostratified nuclei, had the appearance of primitive endodermal epithelium and was positive for carcino-embryonic antigen. In contrast, in the other portion of the adenocarcinoma which had the predominant component of periductal invasion, neoplastic cells had an irregular, eosinophilic cytoplasm, resembled ordinary pancreas adenocarcinoma of ductal origin and was positive for CA19-9. Neuro-endocrine and alpha-fetoprotein-positive cells with a primitive appearance were scattered among the neoplastic epithelial linings. In addition, a vimentin-positive sarcomatoid component intermingled with the adenocarcinoma. These findings suggest that the adenocarcinoma observed in this tumor with the primitive appearance also had a primitive phenotype. This was evidenced by immunohistochemistry and the divergent directions of differentiation. This particular case illustrates that pancreas adenocarcinoma of the ordinary histologic type can arise secondarily from the more primitive neoplastic cells during carcinogenesis within the pancreatic duct.

Osteoclastic giant cell tumor of the pancreas. An immunohistological study and review of the literature

A case of an osteoclastic giant cell tumor of the pancreas is presented. The different surgical specimens during the forty months of observation suggest that the histological feature of the tumor has changed. Although immunohistological studies were performed, the histogenesis remains obscure. Additional 19 cases of the literature were briefly reviewed.

Osteoclast-like giant cell tumor of the pancreas: immunophenotypic similarity to giant cell tumor of bone

An immunophenotype was performed on an osteoclast-like giant cell tumor of the pancreas using a panel of antibodies to epithelial and leukocyte antigens. Several antibodies to cytokeratin and carcinoembryonic antigen were negative in the tumor. Osteoclast-like cells were positive for CD4, CD13, CD45, CD68, CD71, and vimentin, but negative for lysozyme and HLA-DR. Mononuclear tumor cells were positive for CD4, CD11c, CD13, CD14, CD45, CD68, CD71, HLA-DR, and vimentin, but negative for lysozyme. The phenotype is similar to that previously described for giant cell tumor of bone. The osteoclast-like cell phenotype is also similar to that reported for normal osteoclasts. The findings support a nonepithelial origin for osteoclast-like giant cell tumor of the pancreas, and suggest a derivation similar to giant cell tumor of bone.

Giant cell tumor of the pancreas of mixed osteoclastic and pleomorphic cell type: evidence for a histogenetic relationship and mesenchymal differentiation

We describe a giant cell tumor of the pancreas composed of a mixture of osteoclastic and pleomorphic cell types. This rare tumor had a unique immunohistochemical profile. Both types of tumor giant cells stained for vimentin, alpha-1-antitrypsin, alpha-1-antichymotrypsin, synaptophysin, muscle actin, and neuron-specific enolase, but not for epithelial markers. Electron microscopy showed cells which resembled primitive fibroblasts and osteoclast with no epithelial features. These findings are most consistent with mesenchymal differentiation. The extensive homologies in immunohistochemical staining of both osteoclastic and pleomorphic giant cells in this case indicates that these cells are histogenetically related.

Fine-needle aspiration cytology of osteoclastic giant-cell tumor of the pancreas

Osteoclastic giant-cell tumor (OGCT) of the pancreas is a rare tumor. We present the fine-needle aspiration (FNA) and bile cytology findings of an OGCT arising in the head of the pancreas in a 72-yr-old male, along with immunocytochemical studies that were done on the cytologic material. The smears showed numerous giant cells with clustered, overlapping, uniform, bland-appearing nuclei with prominent nucleoli consistent with osteoclastic-type multinucleated giant cells. A second population of mononucleated cells appearing singly or in groups having similar nuclear features was also present. Immunocytochemical studies performed on the FNA and bile duct fluid material demonstrated positive staining of the malignant cells for vimentin, alpha-1 antichymotrypsin, and alpha-1 antitrypsin and negative staining for high- and low-molecular-weight cytokeratin, pooled monoclonal cytokeratin, epithelial membrane antigen, and carcinoembryonic antigen. Although not definitive, these studies are supportive of a mesenchymal-stromal histogenesis of this unusual pancreatic malignancy.

Malignant fibrous histiocytoma (giant cell type) of the pancreas. A distinctive variant of osteoclast-type giant cell tumor of the pancreas

Malignant giant cell tumors of the pancreas are rare neoplasms which have been generally thought to represent epithelial malignancies of either acinar or ductal epithelium. The authors have studied a tumor of the pancreas that was characterized histologically by a proliferation of benign-appearing osteoclast-type giant cells in association with atypical, often bizarre mononuclear cells. Immunohistochemical studies demonstrated negative staining of the tumor cells with epithelial markers, including low-molecular weight keratins, carcinoembryonic antigen and epithelial membrane antigen, and positive staining with vimentin antibodies, supporting a fibroblastic line of differentiation. Electron microscopic examination also showed absence of ultrastructural features of epithelial differentiation such as microvilli, intercellular junctions, or desmosomes. The authors believe the current case represents a true sarcoma of the pancreas, currently best classified as a malignant fibrous histiocytoma, giant cell type. This tumor should be distinguished from the epithelial type of osteoclastic giant cell tumor of the pancreas.

Osteoclast-type giant cell neoplasms of the parotid gland

The parotid gland is added to the list of parenchymal organs, notably the pancreas, in which osteoclast-like cells appear as constituent cells in their neoplasms. The cells' role in the neoplasms is a reactive one or, more rarely, as an integral element in an osteoclast-type giant cell neoplasm or so-called osteoclastoma. Distinctive in histological appearance, the osteoclast-type giant cell neoplasm is a malignant lesion that, to date, has been described only in the pancreas and parotid glands. This report presents examples of each type of giant cell lesion in the parotid gland.

S-100 protein localization in minor salivary gland tumours: an aid to diagnosis

The clinician is almost entirely dependent on the histopathologist to accurately diagnose minor salivary gland tumours, but in some cases the histological interpretation of the specimen is very difficult. Recently it has been demonstrated using immunohistochemical techniques that S-100 protein is present in some salivary gland tissues and its localization has been used as an aid in the differentiation of major salivary gland tumours. To assess its value in the diagnosis of minor salivary gland tumours it was localized in sections from 15 such tumours using both a standard peroxidase-antiperoxidase (PAP) and a newly developed immunogold-silver staining sequence (IGSS) technique. Strong staining for S-100 protein was seen in the nuclei and cytoplasm of the cellular areas and also in the cells in the chondroid and myxoid areas of pleomorphic adenomas. Generally the staining was more intense and widespread with the IGSS method. No staining was observed in any of the other tumour types. We conclude that S-100 protein localization is a valuable aid in the differentiation of minor salivary gland tumours. Furthermore, the IGSS method enables more sensitive 'reading' of the staining reaction.

Osteoclast-type giant cell tumour of the pancreas

Two cases of osteoclast-type giant cell tumour of the pancreas (OGTP) are presented and compared with similar tumours of other locations and pancreatic carcinomas. One of the tumours was analyzed by immunohistochemical methods. The mononuclear stromal cells and osteoclast-like giant cells, which characterize this very rare neoplasm, reacted with an antibody against vimentin, but were not decorated by antibodies against lysozyme, alpha-1-ACHT, alpha-1-AT. Pleomorphic mononuclear cells in osteoid additionally contained osteonectin and could thus be identified as osteoblasts. Only the tumour glands stained positively with panepithelial keratin antibodies and antibodies against the keratin polypeptides 7, 18, 19. These results demonstrate for the first time the mesenchymal differentiation of the OGTP, which in some cases is also able to form epithelial structures. The immunohistochemical reactions and the characteristic morphology of the tumour show the OGTP to be an entity which must be differentiated from pancreatic carcinoma, especially from its giant cellular subtype.

Sarcomatoid carcinoma of the pancreas presenting as gastric carcinoma: clinicopathologic and ultrastructural findings

The clinicopathologic and ultrastructural features of a sarcomatoid carcinoma of the pancreas presenting initially as gastric carcinoma are described. By light microscopy, the tumor contained cellular patterns similar to those present in tumors of mesenchymal origin. Spindle cell areas arranged in a storiform pattern were present. Ultrastructurally, bundles of cytoplasmic microfilaments were present in the cell cytoplasm and were similar in distribution to those found on fine structural examination in tumors of mesenchymal origin. Rows of desmosomes were found between cells supporting an epithelial origin for this tumor. Following initial therapy, metastatic tumor produced polypoid lesions in the small intestine resulting in recurrent small bowel intussuceptions. Our findings indicate that sarcomatoid carcinoma of the pancreas, by both light and ultrastructural examination, is a heterogenous tumor at the cellular level and may be a cause of repeated intussuception when intraluminal compromise occurs.