Desmin positivity in primitive neuroectodermal tumors of childhood.

In this report, we describe two rosette-forming primitive neuroectodermal tumors that were found to contain desmin by both immunohistochemistry and Western blotting. Electron microscopy on both cases was consistent with primitive neuroectodermal tumors and revealed that the tumor cells contained cytoplasmic bundles of intermediate filaments. In both cases, studies for MyoD1 protein using immunohistochemistry and Western blotting were negative. Thus, the detection of desmin in a pediatric neoplasm does not absolutely exclude the diagnosis of primitive neuroectodermal tumor and should not be considered as prima facie evidence that a small-cell tumor is a rhabdomyosarcoma.     

Intermediate filamentous proteins in adult granulosa cell tumors. An immunohistochemical study of 25 cases.

Adult granulosa cell tumors (AGCTs) are classified as sex cord-stromal tumors of the ovary. However, they may be confused with other primary ovarian neoplasms. Intermediate filaments, specifically vimentin and cytokeratins, have been identified in AGCTs by immunohistochemistry performed on frozen and formalin-fixed, paraffin-embedded tissue and two-dimensional electrophoresis. Recently, however, immunohistochemical demonstration of cytokeratin has been used as supporting evidence of epithelial rather than sex cord-stromal differentiation in ovarian neoplasia. To investigate further intermediate filamentous proteins in AGCTs, 25 such tumors were studied by immunohistochemistry in formalin-fixed, paraffin-embedded sections. Cytoplasmic staining was observed, frequently in a distinct punctate, paranuclear pattern, in 14 of 25, 14 of 25, and seven of 17 tumors using monoclonal antibodies AE1/AE3, CAM 5.2, and 35BH11, respectively, which share the ability to detect low molecular weight cytokeratins. Staining for cytokeratin was not seen in any of the 17 tumors studied using the antibody 34BE12. Twenty-three of 25 tumors showed strong positivity for vimentin, characteristically seen as globoid paranuclear staining. Nine of 25 tumors contained desmin, which was restricted to the intermixed spindle cell, cortical type stromal component of the tumors. These patterns of immunoreactivity for intermediate filaments, particularly cytokeratins, are different than in common epithelial tumors of the ovary and may be useful in the differential diagnosis of ovarian neoplasia. Moreover, the immunohistochemical detection of cytokeratins should not be used as a criterion for excluding AGCT from the differential diagnosis of an ovarian neoplasm.     

Rhabdoid papillary meningioma.

We have studied an uncommon case of rhabdoid papillary meningioma in a 15-year-old boy with a dura-based mass arising in the left posterior fossa. The patient exhibited prominent extracranial extension during the past 6 years, consisting of a mixture of both perivascular pseudopapillary growth and rhabdoid cytologic features of neoplastic meningothelial cells. The meningothelial features were evidenced by the focal whorl formation of tumor cells, coexpression of epithelial membrane antigen and vimentin, and ultrastructural findings of interdigitated cytoplasmic process and intercellular junction. However, the regional and histologic resemblances to ependymoma were further complicated by unexpected focal expression of glial fibrillary acidic protein, neurofilament, and alpha-smooth muscle actin of the tumor cells. The rhabdoid morphology was characterized by sheets of tumor cells with eccentric nuclei and abundant eosinophilic cytoplasm with often recognizable intracytoplasmic hyaline inclusions. These inclusions revealed ultrastructural paranuclear whorls of intermediate filaments, ruling out the other forms of intracytoplasmic eosinophilic inclusions resembling rhabdoid morphology. Diagnosis of an unusual rhabdoid papillary meningioma with aggressive behavior is resoluble by immunohistochemical and ultrastructural analyses.     

Epithelioid leiomyosarcoma of the stomach. A case study of the intermediate filaments

The intermediate filament typing of skeletal and smooth muscle tumors has shown that these neoplasms are characterized by the combined expression of desmin and vimentin intermediate filaments. A case of epithelioid leiomyosarcoma of the stomach was studied by conventional light microscopy and by indirect immunofluorescence using tissue-specific antibodies against intermediate filaments. The tumor cells labeled strongly with vimentin antibodies and were negative for desmin and prekeratin. This peculiar staining pattern may be the result of poor differentiation of the tumor cells with resultant loss of expression of desmin, or may be due to origin from a distinctive smooth muscle cell characterized by the exclusive expression of vimentin intermediate filaments.     

Histogenesis of Human Renal Cell Carcinoma by using Electron Microscopy and Immunohistochemical Techniques

Electron microscopy and immunohistochemical techniques are powerful tools for the determination of tissue origin. Both techniques have been used in the current experiment for histogenesis of renal cell carcinoma. Fifty kidney tumors were subjected to immunohistochemical detection for intermediate filaments cytokeratin and vimentin, which are normally expressed in epithelial tissue and mesenchymal tissues, respectively. Twenty cases of the above were examined by electron microscopy for detection of ultrastructure features. From each kidney, two specimens were taken, one from the diseased area and another far from it to serve as a control. Immunohistochemical study revealed in cases of renal cell carcinoma, cytokeratin and vimentin were expressed alone in 44% of cases, and 40% of cases, respectively. Twelve percent of cases were coexpressed with both cytokeratin and vimentin. Electron microscopic study of diseased specimens revealed the expression of desmosomes which was observed in almost all tumor specimens. The expression of the vimentin in some cases either alone or with cytokeratin was interpreted as a change in the characters of some tumor cells which indicates the need for additional techniques in such cases to get the proper interpretation. The prevalence of the expression of cytokeratin and the persistence existence of desmosomes indicate the epithelial origin of the tumor. This data is very beneficial for determination of line of therapy and follow up of the patients. The results confirm the power of combined use of both immunohistochemistry and electron microscopy in the field of histogenesis.     

Unusual sinonasal small-cell neoplasms following radiotherapy for bilateral retinoblastomas

Two patients developed sinonasal small-cell neoplasms that arose 22 years and 37 years, respectively, following radiotherapy for bilateral retinoblastomas. The tumors were composed of small cells with scant cytoplasm and had a few scattered Homer-Wright rosettes. Immunohistochemically, one tumor was positive for keratin (CAM 5.2 and AE1/AE3), epithelial membrane antigen, and neuron-specific enolase. The other neoplasm was immunoreactive for keratin (CAM 5.2 only) and neuron-specific enolase; it also had focal immunopositivity for S-100 protein, desmin, and muscle-specific actin. Both were negative for CEA, vimentin, melanocyte-specific antigen (HMB45), chromogranin A, synaptophysin, Leu-7, 200 kd neurofilament, and retinal S-antigen. Despite aggressive multimodal therapy, the patients died of metastatic tumor 7 months and 10 months following their initial diagnosis, respectively. Although osteosarcoma is the most frequent second cancer following bilateral retinoblastomas, some patients develop clinically aggressive sinonasal small-cell tumors that are difficult to place into conventional classifications. Both of our cases showed evidence of multidirectional differentiation; one tumor labeled with epithelial and neural markers, and the other expressed epithelial, neural, and myogenous antigens.     

Astroblastoma: electron microscopy and immunohistochemical findings: case report

The clinical, histological, immunohistochemical, and electron microscopic features of a cerebral astroblastoma are reported. The patient is a young woman with a superficial parietal tumor. Macroscopic findings include a well-delineated superficial nodule with a hard central core. Histological study disclosed a predominantly papillary tumor with hyalinized vessels. Tumor cells were scarcely positive with immunohistochemical stain for glial fibrillary acidic protein, extensive and diffusely positive with vimentin and neuron-specific enolase, and intensely positive with S-100 and epithelial membrane antigen in the papillary areas. Ultrastructural study showed abundant intermediate filaments forming bundles in tumoral cytoplasms, membrane junctions, and external laminae when cells were in contact with collagen fibers. Based on immunohistochemical and ultrastructural characteristics, we believe that the filaments seen in tumor cells are mainly vimentin filaments. These peculiar immunohistochemical patterns in a glioma may aid in the histological diagnosis of this rare tumor type.     

Fine structure of glioblastoma multiforme with "adenoid formation"

Glioblastoma multiforme with "adenoid formation" (Kepes) in the temporal lobe of a 70 year old man was presented. In addition to the classical features of glioblastoma multiforme, the tumor presented a pattern of anastomosing trabeculae of polygonal cells, mimicking epithelial tubules, in a myxoid stroma. On electron microscopic examination, the tumor cells were devoid of well-developed cytoplasmic processes. The cytoplasm of some tumor cells contained glycogen particles and lipid vacuoles in addition to usual organelles. The cell surface was partly covered by basal lamina associated with half desmosomes and had occasional filopodia-like cytoplasmic projections. A few tumor cells contained a dense intracytoplasmic accumulation of glial filaments. Intercellular junctional complexes were poorly developed. There was no evidence of differentiation of tumor cells toward ependymal cells or epithelial cells. These electron microscopic findings suggest that this tumor is predominantly composed of immature astrocytes. In spite of a superficial resemblance to adenocarcinoma on light microscopy, the tumor cells are devoid of the differentiating features of epithelial neoplasms, and their ultrastructure is essentially similar to that of glioblastoma multiforme.     

Site-specific growth of the prostate xenograft line UCRU-PR-2

A xenografted small-cell, undifferentiated prostate (SCUCP) cancer line, UCRU-Pr-2, was implanted at different sites within nude mice to examine the effect of local environmental factors on tumor growth and behavior. All tumors that grew were small-cell carcinomas. Fragments implanted within muscle and under the kidney capsule were locally invasive; however, tumors that grew subcutaneously or intraperitoneally showed no invasion. UCRU-Pr-2 did not grow in the spleen or the liver. No induced metastases were observed in the lung after intravenous injection. The sites of implantation did not allow the outgrowth of subpopulations as detected by the parameters used: light and electron microscopy, expression of tumor markers, levels of hormone production, and DNA flow cytometry. Electron microscopy, which showed both glandular and neuroendocrine differentiation within the same cell, does not support a dual-cell origin of SCUCP.     

Spindle-cell carcinoma of the upper aerodigestive tract mucosa. An immunohistologic and ultrastructural study of 18 biphasic tumors and comparison with seven monophasic spindle-cell tumors

The histogenetic origin of the spindle-cell component of spindle-cell carcinoma of the head and neck mucosa remains controversial. The spindle cells have been considered a variant growth pattern of squamous-cell carcinoma, a non-neoplastic mesenchymal reaction, and a malignant admixture of epithelial and mesenchymal neoplasm. To evaluate the spindle-cell component, we studied 25 tumors (18 biphasic and seven monophasic) by utilizing the following: an avidin-biotin complex immunoperoxidase technique with a variety of antikeratin antibodies (AE1, AE3, CAM 5.2, 35BH11, and polyclonal Dako) and a monoclonal antivimentin antibody, and an avidin-biotin alkaline phosphatase double-labeling technique to detect coexpression of keratin and vimentin. The immunohistologic staining pattern was compared with electron-microscopic studies. Eight of 18 biphasic neoplasms contained immunoreactive keratin in the spindle-cell component that was distributed focally in a minority of cells in 3 tumors and diffusely throughout five of the neoplasms. Four of seven ulcerated monophasic spindle-cell tumors devoid of histologic squamous-cell carcinoma also were keratin positive, confirming epithelial differentiation. The majority of the spindle cells in all the tumors contained vimentin intermediate filaments. In three immunoperoxidase keratin positive biphasic tumors examined with alkaline phosphatase double labeling, occasional spindle cells were found that coexpressed keratin and vimentin and were interspersed with cells expressing either intermediate filament. Electron microscopy was performed on the spindle-cell component of 13 tumors, nine biphasic and four monophasic. Of the biphasic tumors, four were immunoperoxidase keratin positive; three of these showed epithelial differentiation by electron microscopy. Five biphasic tumors were keratin negative, and three tumors had epithelial differentiation by electron microscopy. Four monophasic spindle-cell tumors were immunoperoxidase keratin positive, and one of these had epithelial features by electron microscopy. Two monophasic tumors were keratin negative and without ultrastructural evidence of epithelial features. By using a combination of immunohistochemical and electron-microscopic observations, we identified evidence for epithelial differentiation in the spindled cells in 11 of 18 biphasic tumors and four of seven monophasic spindle-cell tumors.     

Small cell carcinoma of the lung and its histological origin. Report of a case.

A rare lung cancer consisting in part of small cell carcinoma of intermediate cell type and in part of well-differentiated papillotubular adenocarcinoma is described. Alcian blue-PAS staining was observed in the cytoplasm of the small cell carcinoma cells; the Grimelius argyrophil reaction was also positive in the cytoplasm of these cells. Electron microscopy revealed neurosecretory granules in the cytoplasm. At autopsy, a small cell carcinoma of intermediate cell type was found with both squamous features and gland formation. The cellularity and histological pattern of this tumor suggested the existence of a transitional pattern between small cell carcinoma of intermediate cell type, squamous cell carcinoma and adenocarcinoma. From the above findings, we think that small cell carcinoma including the intermediate cell type is derived from respiratory epithelial cells of endodermal origin with dedifferentiation of those cancer cells into neurosecretory cells.     

Fluorescence study of renal cell carcinoma with antibodies to renal tubular antigens, intermediate filaments, and lectins

A fluorescence study was performed in 16 renal cell carcinomas using antibodies to renal tubular antigens (RTA), two intermediate filaments, cytokeratin and vimentin, and two lectins, soybean agglutinin (SBA) and peanut agglutinin (PNA). We observed the presence of RTA, cytokeratin, and vimentin in all of our specimens. The expression of vimentin, the cytoskeletal protein of mesenchymal cells, was considered to be very interesting feature of the tumor. Binding sites of SBA, normally present in glomeruli, proximal and distal tubules, were detectable in the neoplastic cells in only 37.5% of our specimens. PNA did not react with the tumor except for the small area of 2 specimens. Lectins may be useful for estimating the characteristics or renal cell carcinoma including its malignant potentials, and antibodies to RTA and intermediate filaments seem to be available for the diagnosis of the tumor in metastatic lesions.     

The cytoskeleton of cultured skin fibroblasts from patients with Huntington's chorea

Cultured skin fibroblasts from patients with Huntington's chorea were prepared for indirect immunofluorescence using monospecific antibodies to tubulin, actin, and fibronectin. The fibroblasts were also visualized by transmission electron microscopy. The fibroblasts were observed after 3 hours of plating and treatment with various concentrations of colcemid and cytochalasin B to test the reaction of the microfibrillar network to stressful conditions. Disorders were not apparent in the cytoskeletal system (microtubules, microfilaments, and intermediate filaments) when compared with normal controls. Fibronectin was arranged in a fibrillar pattern similar to that seen with actin immunofluorescence. This colinear arrangement was not disturbed in Huntington's chorea cells. Microtubules, microfilaments, and 10-nm intermediate filaments became more parallel as the incubation period increased from 3 to 24 hours. This study showed that the cytoskeleton and the attachment of one surface protein (fibronectin) are not affected in Huntington's chorea.     

Vimentin Expression in Spermatogenic and Sertoli Cells is Stage-related in Rat Seminiferous Epithelium

Monoclonal and polyclonal antibodies were used in indirect immunofluorescence microscopy to localize vimentin intermediate filaments in the rat seminiferous epithelium. During stages XII-V of the epithelial cycle, the Sertoli cells showed a reaction in the perinuclear area and vimentin-positive extensions, projecting toward the developing spermatid bundles, were also seen. During stages VI-XI these extensions were small and narrow. Monoclonal antibody to vimentin gave a granular reaction in the peripheral region of the flagella of steps 16-19 spermatids. Western blotting indicated a specific reaction with a Mr 58,000 polypeptide in isolated seminiferous tubules and in epididymal spermatozoa. Our results suggest that vimentin filaments in Sertoli cells may be regulated cyclically in a stage-dependent manner. The granular reaction in the spermatid flagellum with the monoclonal antibody suggests that vimentin in germ cells is organized differently from that in somatic Sertoli cells.     

Small-cell undifferentiated carcinoma of the cervix. A clinicopathologic, ultrastructural, and immunocytochemical study of 15 cases

The clinicopathologic, immunocytochemical, and ultrastructural features of 15 small-cell undifferentiated carcinomas (SCUC) of the uterine cervix are reported. Patients ranged in age from 25 to 87 (median, 42 years) and presented as stages IB (nine patients), IIA (one patient), IIB (two patients), IIIB (two patients), and IV (one patient). A variety of treatment regimens were employed. Ten patients died of disease (3-71 months; median, 11 months), one patient has a suspicious lung nodule 10 months after diagnosis, one patient is comatose with brain metastases 4 months after diagnosis, and three patients are alive and well 5, 11, and 78 months after diagnosis. Histologically and cytologically, the tumors were identical to pulmonary small-cell undifferentiated carcinoma. Six tumors were associated with other forms of carcinoma, in situ or invasive or both, including epidermoid carcinoma in situ (two cases), adenocarcinoma in situ and epidermoid carcinoma in situ (one case), adenocarcinoma (three cases), and epidermoid carcinoma (three cases). All 13 tumors expressed one or more epithelial markers and at least one neuroendocrine marker. Electron microscopy demonstrated dense-core granules in six of seven tumors, dendrite-like processes in seven tumors, filament bundles in four tumors, and intracytoplasmic lumina in one tumor. Small-cell undifferentiated carcinoma of the cervix is an aggressive tumor with a propensity for rapid metastasis and high mortality. These tumors may demonstrate multidirectional differentiation, including the frequent expression of neuroendocrine features.     

Solid and papillary epithelial neoplasm of the pancreas. An ultrastructural and immunocytochemical study of six cases

Solid and papillary epithelial neoplasms of the pancreas from six female patients were studied using immunohistochemistry and electron microscopy to define better their histogenesis. The tumors ranged in diameter from 5 to 15 cm (average: 9 cm), and, on cross section, most had areas of hemorrhage and necrosis, sometimes extensive. Microscopically, there was a solid and pseudopapillary pattern, with tumor cells typically having ovoid nuclei with delicate folding and indistinct nucleoli. Of note were the following: a relatively low mitotic rate (range: 0-6/20 hpf), the presence of hyaline globules (four of six cases), and collections of foam cells (three of six cases). Staining for cytoplasmic argyrophil granules was negative in each case. Ultrastructurally, the solid and papillary epithelial neoplasms of the pancreas showed evidence of acinar or ductular differentiation. Two contained zymogen granules, one had intermediate filaments (probably keratin), and three had abundant rough endoplasmic reticulum and mitochondria. Immunostaining was positive for chymotrypsin (six of six cases), trypsin (four of six), and amylase (three of six). None was positive for alpha-1-antitrypsin, neuron-specific enolase, pancreatic polypeptide, gastrin, glucagon, somatostatin, or insulin. The findings support an origin from exocrine pancreas, and follow-up indicates a low rate of malignancy, with local recurrence in two of the six patients.     

Intra-abdominal desmoplastic small round-cell tumor. Report of 19 cases of a distinctive type of high-grade polyphenotypic malignancy affecting young individuals.

Nineteen cases of a distinctive type of malignant small-cell tumor are presented. The main features of the entity are as follows: a predilection for adolescent males (mean age: 18.6 years); predominant or exclusive intra-abdominal location, with only inconstant and secondary organ involvement; nesting pattern of growth; focal rhabdoid features; intense desmoplastic reaction; immunohistochemical reactivity for epithelial [keratin, epithelial membrane antigen (EMA)], neural [neuron-specific enolase (NSE)], and muscle (desmin) markers; and highly aggressive behavior. It is proposed that this represents yet another member of the continuously enlarging and evolving family of small round (blue) cell tumors of infancy and childhood that features, more than any other member of this group, the capacity for simultaneous multidirectional phenotypical expression.     

Rat glomerular epithelial cells in culture express characteristics of parietal, not visceral, epithelium.

Glomerular epithelial cells (GEC) in culture are derived from intact isolated glomeruli. Although there is general agreement about distinguishing GEC from mesangial and endothelial cells, there is still uncertainty regarding the visceral versus parietal origin of cultured GEC. If these cells are to provide a useful model system, it is necessary to establish well-defined cell populations. The purpose of this study was to evaluate this important issue by comparing the characteristics of cultured GEC with glomerular epithelium from rat kidney sections. By electron microscopy, GEC were polygonal, with cilia and desmosomes between cells, similar to parietal cells in situ. Because intermediate filaments are specifically expressed in differentiated cells in the kidney, the expression of intermediate filaments in cultured GEC were compared with those of intact glomeruli. Cultured GEC are positive for cytokeratin and negative for vimentin and desmin, identical to parietal cells in situ. In contrast, podocytes are positive for vimentin and desmin and negative for cytokeratin. In vivo, podocytes express gp330 and puromycin-aminonucleoside (PAN) susceptibility, which are used as markers for cultured GEC. Immunoperoxidase staining of rat kidney sections with monoclonal anti-gp330 demonstrated gp330 localization to the cell surface and coated pits of the parietal cells, similar to its localization in podocytes. The presence of gp330 in cultured GEC was confirmed by immunoblot. PAN administration to rats induced vacuolization and detachment from the basement membrane in the parietal cells of Bowman's capsule, similar to the cytotoxicity observed in podocytes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Histogenesis of benign pleomorphic adenoma (mixed tumor) of the major salivary glands. An ultrastructural and immunohistochemical study

Twenty-two benign pleomorphic adenomas of the major salivary glands were studied by transmission electron microscopy and immunohistochemical techniques (three cases) in order to characterize the cell types comprising the epithelial and so-called mesenchymal regions of the tumors. Light- and electron-microscopic studies showed the tumors to consist of variable mixtures of neoplastic ductular epithelial cells, rare acinar cells, and metaplastic myoepithelial cells. Many of the loosely organized "stromal cells" contained structures indicative of their myoepithelial origin, e.g., perinuclear tonofilaments, ectoplasmic actin microfilaments, and remnants of basement membrane. Polyclonal antikeratin antisera strongly stained ductular epithelial and myoepithelial cells, squamoid cell nests, and periductular myoepithelial cells, whereas myxoid and chondroid cells were less intensely stained. Monoclonal cytokeratin antibody AE1 stained only the ductular epithelial cells in both the normal glands and tumors. In contrast, S-100 protein, which is present only in scattered acinar cells and myoepithelial cells in the normal parotid gland, was found in the ductular and periductular myoepithelial cells, isolated myxoid cells, and chondroid and cartilagenous cells in the tumors. Actin was found in all the cell types of the tumor but staining was strongest in the ducts. Double immunofluorescence staining for cytokeratin and vimentin revealed coexpression of both types of intermediate filaments in occasional normal acinar and intercalated duct myoepithelial cells, and in some cells in the myxoid and chondroid regions of the tumors. In the tumors, vimentin was present in occasional periductular myoepithelial cells, stellate myxoid cells, and especially in chondroid cells and chondrocytes. Our findings indicate that benign pleomorphic adenomas of the major salivary glands are pure epithelial cell tumors. The histologic complexity of these neoplasms is due to the ability of the neoplastic ductular myoepithelial cell to modulate its morphologic appearance and intermediate filament composition, and to produce large amounts of matrix substances. We further postulate that these tumors arise from neoplastically transformed intercalated ducts.     

Crossreactions between an I-A allospecificity and the cytoskeleton of glomerular epithelium and of vascular smooth muscle

During studies to investigate the localization of Ia antigens in normal mouse kidney, a monoclonal antibody (Mab) specific for I-Ab by microcytotoxicity criteria was found to crossreact with a tissue antigen present in the glomeruli and vasculature of murine tissues, irrespective of their Ia haplotype, as well as in human kidneys. Immunofluorescence and immunoperoxidase studies of frozen tissue sections revealed that the antigen responsible for the crossreaction was present in the cytoplasm of glomerular epithelial cells and of smooth muscle of blood vessels. The immunofluorescence pattern of primary cultures of human glomerular epithelial cells and of a glioblastoma cell line indicated that the crossreactive antigen forms part of the cytoskeleton, and resembled the pattern observed with a monoclonal against vimentin, one of the intermediate filaments. Thus this Mab, which is directed against mouse alloantigen Ia.20 in microcytotoxicity was found to crossreact with a cytoskeletal component present in the mouse, as well as in human glomerular epithelial and smooth muscle cells.