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Malignant fibrous histiocytoma of the uterus.

A primary, malignant pleomorphic giant cell tumor of the uterus was studied by light and electron microscopy. The tumor was characterized by spindle cells, plump epithelioid cells, pleomorphic giant cells, osteoclast-like giant cells, and foamy xanthomatous cells. Histochemically, tumor cells did not show either myogenic or epithelial characteristics. Immunohistochemically, tumor cells were devoid of evidence of desmin, cytokeratin, myoglobin, and lysozyme (muramidase), but vimentin was weakly positive, and alpha 1-antichymotrypsin was weakly positive in the cytoplasm of pleomorphic giant cells. Ultrastructurally, tumor cells did not show either myogenic or epithelial features, but they resembled a variant of malignant fibrous histiocytoma. The present case was classified as a storiform-pleomorphic and giant cell type of malignant fibrous histiocytoma of the soft tissues. The uterus is considered to be an additional possible site of malignant fibrous histiocytoma.

Female↗

Pleomorphic leiomyosarcoma of the adrenal gland with osteoclast-like giant cells.

Pleomorphic leiomyosarcoma (PLMS) of the adrenal gland is a rare tumor in an unusual location. A primary PLMS of the left adrenal gland is reported in a 59-yr-old Mexican woman who presented progressive flank pain and weight loss. The tumor measured 16 cm in diameter, showed markedly pleomorphic and osteoclast-like giant cells, necrosis, and high mitotic activity (average 15 per 10 high-power fields). The phenotype was supported by light microscopy and corroborated by immunohistochemistry. The neoplastic cells were strongly positive for muscle-specific actin, desmin, vimentin, and p53. They were negative for CD34, HMB45, estrogen receptors, and S-100 protein. The percentage of Ki-67 positive neoplastic cells was 7.6%. DNA content analysis by flow cytometry showed that tumor was diploid, with a high level of apoptosis. Extra-adrenal primary sites of origin were clinically excluded. The patient developed local recurrence and liver metastases 12 mo after initial treatment. She then received adjuvant chemotherapy and radiotherapy and the metastasis was resected. Twenty-four months later, she is alive with no evidence of disease. This is the second case of adrenal PLMS reported. This case exhibited a high histologic grade, aggressive behavior, and p53 overexpression, but diploid DNA content.

Adrenal Gland Neoplasms↗

Spindle cell and pleomorphic lipoma: an immunohistochemical study and histogenetic analysis.

Twenty-two spindle cell lipomas and seven pleomorphic lipomas were investigated immunohistochemically in order to study the differentiation of the non-adipocytic elements. In all cases, neither spindle cells nor pleomorphic cells reacted with antibodies to a monocyte/macrophage antigen (MAC-387), fibronectin, laminin or type IV collagen. The absence of demonstrable basement membrane material argues against the possible prelipoblastic nature of these cells. With the antibody to S-100 protein, spindle cells were immunonegative, whereas pleomorphic cells sometimes revealed an intracytoplasmic weak to moderate staining reaction. In the light of what is known about the development of adipose tissue, our results would support the hypothesis of Bolen and Thorning (Am J Surg Pathol 1981; 5: 435-441) that spindle cell lipoma is composed of adipocytes and non-fat storing immature mesenchymal cells. It would appear that pleomorphic lipoma is similarly derived but that in some cases adipocytic differentiation is also abnormal. The characteristic clinical distribution of these two types of tumour may be of relevance in determining the cause of these unusual benign patterns of differentiation.

Adult↗

Peripheral T-cell non-Hodgkin's lymphomas of low malignancy: prospective study of 25 patients with pleomorphic small cell lymphoma, lymphoepitheloid cell (Lennert's) lymphoma and T-zone lymphoma. The Kiel Lymphoma Study Group.

Peripheral T-cell lymphomas comprise a heterogenous group of low- and high-grade malignancies differing in their histopathological appearance and also in clinical and prognostic aspects. We prospectively studied 25 patients with low-grade peripheral T-cell lymphomas: pleomorphic, small cell lymphoma (PSC) (n = 9), lymphoepitheloid (Lennert's) lymphoma (LEL) (n = 12) and T-zone lymphoma (TZL) (n = 4). The median patient age was 55 years (range 19-75 years); the male to female ratio was 1.5. 13 patients (52%) had limited stages (I+II), 12 patients (48%) had advanced disease (stage III+IV). 21 patients received the COPBLAM/IMVP-16 regimen. Two patients received more intensive treatments; two received less intensive therapy. Complete remissions were achieved in 16/25 patients (64%). The median observation time of surviving patients was 30 months (range 5-72 months). The actuarial overall survival and event-free survival at 2 years of 21 patients receiving COPBLAM/IMVP-16 were 69% and 35%, respectively. Intensive chemotherapy led to complete remissions in about 60% of the patients and to long-term disease-free survival for one-third. The observed clinical courses illustrate the aggressive nature of PSC, LEL and TZL.

Adult↗

Myofilament localization and immunoelectron microscopic detection of muscle-specific actin in neoplastic myoepithelial cells in pleomorphic adenomas and myoepitheliomas.

Elucidating the cellular characteristics of the nonluminal or myoepithelial cells of pleomorphic adenomas is one approach to establishing the diagnostic criteria for myoepitheliomas. Ultrastructural features of nonluminal tumor cells in 22 pleomorphic adenomas and of tumor cells in 9 myoepitheliomas were assessed from micrographs of routinely fixed and epoxy resin-embedded samples. Recognizable myofilaments were only moderately prominent in 1 myoepithelioma. In the rest of the cases, irrespective of whether nonluminal cells of pleomorphic adenomas or tumor cells of myoepitheliomas were spindle, angular, round, or plasmacytoid in form, myofilaments were noted only in one third of the cases and were present even in these in a small proportion of the tumor cells. Intermediate filament accumulations and basal lamina were more frequent findings associated with nonluminal tumor cells. Six pleomorphic adenomas and 2 myoepitheliomas had been fixed in half-strength glutaraldehyde and embedded in LR White resin for immunoelectron microscopic detection of muscle-specific actin. In 3 (2 pleomorphic adenomas and myoepitheliomas) of these 8 cases, readily visualized bands of filaments in many tumor cells were strongly labeled by the colloidal gold probe detecting muscle-specific actin even when myofilaments were minimal and infrequent in 2 cases and undetectable in the third by routine transmission electron microscopy. Lack of myofilament detection by immunocytochemistry or routine electron microscopy does not exclude a diagnosis of pleomorphic adenoma or myoepithelioma when growth patterns and cytology indicate such diagnoses. Immunoelectron microscopy, in fact, shows that muscle-specific actin can be detected even when myofilaments or muscle actin are apparently absent or minimal by routine electron microscopy or immunohistochemistry, respectively. Because examples of pleomorphic adenoma and myoepithelioma each with similar histologic and cytologic features of the myoepitheliomatous cells can have variable degrees or complete absence of expression of myofilaments or muscle-specific actin, the time-honored term myoepithelial for the nonluminal cells of pleomorphic adenomas and the term myoepithelioma are legitimate even in the absence of those markers that are specific for normal myoepithelial cells.

Actins↗

Pleomorphic giant cell adenocarcinoma of the prostate: report of 6 cases.

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.

Adenocarcinoma↗

Cutaneous pleomorphic large cell lymphoma.

The case of a primary cutaneous pleomorphic large cell lymphoma occurring in a twenty-one-year-old woman who presented with a blue-reddish nodule on her left cheek of three months' duration is presented. The tumor consisted of pleomorphic blast cells showing high mitotic activity. On immunohistochemical examination, the majority of the tumor cells expressed CD 3 (Leu-4), CD 4 (Leu-3), HLA-DR CD 30 (Ki-1/Ber-H 2), and CD 25 (IL2 receptor). Twenty-two months after excision of the tumor there is no detectable systemic spread of the lymphoma. This case provides further evidence for recent observations that primary cutaneous Ki-1-positive large cell lymphomas without lymph node involvement may have a favorable prognosis after local treatment despite showing histologic pattern of malignancy.

Adult↗

Multiple spindle cell lipomas: a report of 7 familial and 11 nonfamilial cases.

Spindle cell lipoma, a variant of a benign lipoma, usually occurs as a solitary, subcutaneous, circumscribed lesion in the posterior back, neck, or shoulders of older men. Multiple lesions are exceedingly rare. To our knowledge, there have been no previous series reported of patients with multiple subcutaneous spindle cell lipomas. We examine the clinicopathologic findings of a group of patients with multiple spindle cell lipomas, including seven with a familial occurrence of this disease. The Soft Tissue Registry of the Armed Forces Institute of Pathology and the consultation files of one of the authors (S.W.W.) from the Department of Pathology at the University of Michigan were searched for patients with multiple spindle cell lipomas. All patients' records, clinical history, and pathology were reviewed. All patients had a minimum of two tumors that met strict morphologic criteria for spindle cell lipoma. Pleomorphic cells, typical of pleomorphic lipoma, were observed in some cases and were acceptable as part of the spectrum of spindle cell lipomas. Associated lesions, family history, ethnic background, daily habits, and natural progression of disease were recorded and compared. Eighteen patients in our files met the criteria for multiple spindle cell lipomas; 4 of the 18 patients were from the same family. Three additional patients had a family history of multiple spindle cell lipomas. The ratio of patients with multiple spindle cell lipomas to all patients with spindle cell lipoma in the two consultation files was 0.5 and 3%, respectively. All of the patients in our study were male; three had a family history of females with less severe disease (fewer and smaller spindle cell lipomas); however, no material from these female patients was available for review. All but four patients presented in their sixth through eighth decades of life; yet, several older patients stated that their first lesion occurred in their fifth decade. Patients had between 2 and >220 lesions, which usually commenced on the posterior neck or back, commonly followed by additional bilateral lesions on the shoulders and upper torso. The natural history of this disease revealed development of multicentric lesions over several years, for both familial and nonfamilial cases. The tumors became more cellular as the disease progressed, often with features of pleomorphic lipoma; however, no patients developed spindle cell liposarcoma. Multiple spindle cell lipomas are rare. The clinical presentation may mimic Madelung's disease (symmetrical lipomatosis). As mentioned above, some cases are familial. Genetic predisposition must be further examined. There appears to be no common ethnic background, environmental exposure, medical condition, or syndrome of associated lesions with multiple spindle cell lipomas.

Adult↗

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.

Antigens, CD↗

Effect of spatial arrangement of the basement membrane on cultured pleomorphic adenoma cells. Study by immunocytochemistry and electron and confocal microscopy.

In a cell line from human pleomorphic adenoma (AP2 cells) we studied the response of these cells to basement membrane proteins. The culture was characterized as myoepithelial-like by transmission electron microscopy and immunocytochemistry. AP2 cells were grown in contact with a reconstituted basement membrane (Matrigel). Cells grown on Matrigel showed conspicuous phenotypic alterations, depending on how the substrate was applied. Cells grown on the top of Matrigel developed a dendritic phenotype, exhibiting thin, long and intercommunicating cytoplasmic extensions resembling normal myoepithelial cells. Cells grown inside Matrigel formed multi-layered clusters. Light, confocal and transmission electron microscopy showed that these clusters were formed by double-layered epithelioid cells delimiting luminal spaces. The cells facing the lumen were cuboidal, showing microvilli at the apical plasmalemmal and junctional complexes. The spatial arrangement of basement membrane is a key modulator of morphogenetic changes and cytodifferentiation of tumour myoepithelial cell lineage in culture.

Adenoma, Pleomorphic↗

Diagnostic criteria for neoplastic myoepithelial cells in pleomorphic adenomas and myoepitheliomas. Immunocytochemical detection of muscle-specific actin, cytokeratin 14, vimentin, and glial fibrillary acidic protein.

OBJECTIVE: Markers for normal salivary gland myoepithelium were used to determine the extent of their expression in the neoplastic myoepithelial (nonluminal) cells of pleomorphic adenomas and then in the tumor cells in myoepitheliomas and to gather information necessary to establish diagnostic criteria, especially muscle actin expression, for myoepitheliomas. STUDY DESIGN: Methanol/acetic acid-fixed and paraffin-embedded tissue was used to immunohistochemically study expression of intermediate and smooth-muscle actin filaments in nonluminal cells in 14 pleomorphic adenomas and to compare this to their expression in five myoepitheliomas. RESULTS: In routine histologic sections, the morphologic variants of nonluminal tumor cells--spindle, stellate, polygonal, angular, and plasmacytoid--in pleomorphic adenoma mirror the spectrum of tumor cells in myoepitheliomas. Immunocytochemical similarities are also apparent. Two specific markers for myoepithelial cells in the normal salivary gland, muscle-specific actin and cytokeratin 14, were both variably, independently, and never uniformly expressed in nonluminal cells of pleomorphic adenoma and tumor cells in myoepitheliomas regardless of their morphology. Cytokeratin 14 in addition labels basal cells of excretory ducts. Both muscle-specific actin and cytokeratin 14 preferentially localized to single layers of periductal cells in pleomorphic adenomas, angular, polygonal, and plasmacytoid cells preferentially expressed cytokeratin 14. Similar patterns were noted in the three myoepitheliomas with reasonable expression of the two markers. Only isolated single cells or small groups of plasmacytoid cells in four pleomorphic adenomas with a significant component of these cells and the two plasmacytoid myoepitheliomas immunostained for muscle-specific actin and cytokeratin 14. In both tumor types, vimentin was nearly uniformly expressed in nonluminal tumor cells of all morphologic types, including plasmacytoid cells. CONCLUSIONS: The range and transition of morphology of nonluminal cells in pleomorphic adenomas is reflected in myoepitheliomas. Incomplete or absent expression of the myoepithelial/basal cell markers, muscle-specific actin, and cytokeratin 14, and the general expression of vimentin is common to both tumors. Because these findings apply to the majority of plasmacytoid cells in pleomorphic adenomas, tumor cells with a similar morphology and immunoprofile are to be expected in myoepitheliomas; the term plasmacytoid myoepitheliomas is thus appropriate regardless of the presence or absence of muscle-specific actin.

Actins↗

Malignant plasmacytoid myoepithelioma of the palate: histological observations compared to benign predominant plasmacytoid myoepithelial cells in pleomorphic adenoma of the palate.

Predominant benign plasmacytoid myoepithelial cells in pleomorphic adenoma and malignant plasmacytoid myoepithelioma cells were investigated morphologically. The cells of both tumors were plasmacytoid in appearance and sheet-like. Immunohistochemically, they were positive for keratin, vimentin, and S-100 protein, and negative for alpha-smooth muscle actin. In the malignant cells, large nuclei with irregular nuclear membranes and distinct nucleoi and occasional intranuclear inclusions and nuclear grooves were seen. Ultrastructural findings showed that the benign cells were richer in intermediate filaments and had fewer mitochondria. The intranuclear inclusions and nuclear grooves of the malignant cells were caused by invagination of the irregular nuclear membranes. Taken in their entirety, the above light microscopical nuclear findings may be useful as an adjunct for distinguishing malignant from benign plasmacytoid neoplastic myoepithelial cells of the salivary gland.

Adenoma, Pleomorphic↗

Benign squamous cells with pleomorphic microvilli in urine or bladder washings.

Exfoliated cells in catheterized urine or bladder washings from 40 patients were observed by light microscopy (LM) and by scanning electron microscopy (SEM). The specimens from seven of these patients (six postmenopausal females and one 85-year-old male) contained squamous cells with pleomorphic microvilli (PMV) on their surfaces. Four of these cases had no bladder lesions by cystoscopic examination. Three patients had recurrent papillary transitional-cell carcinoma of the bladder, and the cytologic specimens from two of them contained transitional cells with PMV. The distinction between squamous and transitional cell is readily made by SEM, based primarily on cell shape and thickness. The presence of PMV on otherwise-benign-appearing squamous cells in urine or bladder washing specimens may be a source of confusion in the interpretation of SEM findings. The presence of PMV on exfoliated squamous cells in cytologic material from the human urinary tract does not seem to have the same diagnostic and prognostic significance as the presence of PMV on transitional cells.

Aged↗

[The effects of HSV-tk suicide gene and wild-type p53 gene on pleomorphic adenoma cells of salivary gland].

OBJECTIVE: To study the therapeutic effects of combined gene therapy of wild type p53 (wt-p53) and herpes simplex virus thymidine kinase (HSV-tk) gene on pleomorphic adenoma cells of salivary gland. METHODS: Wild type p53 and HSV-tk gene were transfected into human pleomorphic adenoma cells of salivary gland by using recombinant adenovirus vector. The efficiency of transfection was checked and gene was expressed by RT-PCR methods. The cell inhibition after transfected was verified by light microscope and MTT. RESULTS: The proliferation of the pleomorphic adenoma cells transfected wt-p53 and HSV-tk gene was inhibited and the cell survival rate decreased to 54% and 38% respectively in 5 days. However, when wt-p53 gene combined with HSV-tk/GCV system, the killing effects was significantly stronger (P < 0.05) and the cell survival rate decreased to 20%. CONCLUSION: Combining p53 gene with HSV-tk/GCV system for gene therapy in pleomorphic adenoma cells of salivary gland is a valuable method.

Adenoma, Pleomorphic↗

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.

Adenocarcinoma↗

An immunohistochemical study of bizarre neoplastic cells in pleomorphic adenoma: its cytological nature and proliferative activity.

The cytological nature and proliferative activity of bizarre neoplastic cells, widely scattered in pleomorphic adenomas of salivary gland origin were studied. Pleomorphic adenomas containing numerous bizarre neoplastic cells were found in four cases, and were equal to 2.9% of all pleomorphic adenomas examined. All four cases presented as well-circumscribed, firm masses measuring less than 1.5 cm in size, located in the palate, and were of 7 months to 4 years duration. Histopathologically, these pleomorphic adenomas were cell rich type, and were well demarcated from surrounding tissues, although their fibrous capsules were partially defective. In addition to characteristic histopathological findings of pleomorphic adenoma, numerous neoplastic cells with bizarre appearance were scattered throughout the lesion, excepting for tubuloductal structures. These bizarre neoplastic cells had irregular-shaped and large nuclei with or without hyperchromatism, although their nucleoli were small and mitotic figures were few. Furthermore, there were many multinucleated giant cells, some of which showed multilobulated nuclei. Neither necrosis nor infarct was seen in the tumors. Immunohistochemically, bizarre neoplastic cells scattered in solid-proliferating areas and myxoid areas were neoplastic myoepithelial cells in nature. There was no statistical significance of MIB-1 labeling indices between pleomorphic adenomas with bizarre neoplastic cells and usual pleomorphic adenomas. The p53 labeling indices were quite low. Although the benign nature of pleomorphic adenomas with numerous bizarre neoplastic cells and hypercellularity, distinguishing such pleomorphic adenomas from various stages of malignant transformation in pleomorphic adenomas and other carcinomas should be made by histological section of submitted biopsy specimen or aspirated content for cytological diagnosis. The present paper suggests that the term 'bizarre cell pleomorphic adenoma' is an appropriate name for this neoplasm, in that it is distinguished from the usual benign pleomorphic adenoma which is easily diagnosed by routinely prepared histological or cytological stainings.

Adenoma, Pleomorphic↗

Pleomorphic (giant cell) carcinoma of the intestine. An immunohistochemical and electron microscopic study.

Pleomorphic (giant cell) carcinomas have been described in the lungs, thyroid, pancreas, and gallbladder. Two pleomorphic carcinomas of the small bowel and two of the large bowel are presented. On light microscopic study, the carcinomas were solid, without squamous or glandular differentiation. The tumors were composed of the following three cell types: gemistocytic (giant) cells, smaller polygonal cells, and spindle cells, with identical immunohistochemical reactions. A panel of monoclonal and polyclonal antibodies was applied. All tumors were found to coexpress keratin and vimentin. A positive reaction for neuron-specific enolase (NSE) was found in three tumors and a positive reaction for chromogranin was found in one tumor. On electron microscopic study, intracytoplasmic whorls of intermediate filaments were seen in the perinuclear area. Dense core "neurosecretory" granules were rarely seen. Intestinal pleomorphic carcinomas are histologically identical to pulmonary giant cell carcinomas. The prognosis is poor due to early tumor spread, with only a few months of postoperative survival. The pleomorphic carcinomas have some of the differentiation characteristics of carcinoid tumors and are best regarded as poorly differentiated variants of neuroendocrine carcinomas.

Aged↗

Fine-needle aspiration biopsy of pleomorphic (giant cell) carcinoma of the pancreas. Cytologic, immunocytochemical, and ultrastructural findings.

Four cases of pleomorphic (giant cell) carcinoma (PGC) of the pancreas, diagnosed by fine-needle aspiration biopsy, are presented. Ancillary immunocytochemical studies were also performed on the smears (four cases) and cell blocks (three cases), along with ultrastructural (electron microscopic) examination of the aspirated specimen (two cases). Three of the four patients were elderly (age range: 44-65 years), and all had large pancreatic masses. A spectrum of cytomorphologic features was encountered, including poorly cohesive bizarre mononuclear cells, many multinucleated tumor giant cells, and associated malignant spindle cells. Prominent cellular cannibalism and cytophagocytosis also were seen. Immunoperoxidase studies demonstrated dual staining of the malignant cells for cytokeratin and vimentin in two cases and exclusive staining for vimentin in the remaining two cases. Ultrastructural examination demonstrated epithelial features in both cases studied. One of the cases demonstrated intracytoplasmic whorled bundles of intermediate filaments, corresponding to pale eosinophilic globular material, appreciated both in the Diff-Quik- and Papanicolaou-stained smears and staining with positive results for vimentin. The immunocytochemical studies suggest that the coexpression of vimentin and cytokeratin within the cells is consistent with a pleomorphic malignancy of epithelial origin. It is speculated that the staining of two of the cases exclusively for vimentin can be seen in either epithelial malignancies with sarcomatoid transformation or, less likely, a pure sarcoma of the pancreas.

Adult↗