A dysfunctional desmin mutation in a patient with severe generalized myopathy

Mice lacking desmin produce muscle fibers with Z disks and normal sarcomeric organization. However, the muscles are mechanically fragile and degenerate upon repeated contractions. We report here a human patient with severe generalized myopathy and aberrant intrasarcoplasmic accumulation of desmin intermediate filaments. Muscle tissue from this patient lacks the wild-type desmin allele and has a desmin gene mutation encoding a 7-aa deletion within the coiled-coil segment of the protein. We show that recombinant desmin harboring this deletion cannot form proper desmin intermediate filament networks in cultured cells, nor is it able to assemble into 10-nm filaments in vitro. These findings provide direct evidence that a mutation in desmin can cause human myopathies.

CD44 isoform expression follows two alternative splicing pathways in breast tissue

The repertoire of distinct CD44 protein isoforms is generated by means of alternative pre-mRNA splicing of 10 variable exons located in the central region of the CD44 gene. We have used human breast ductal carcinoma as a model to identify two alternative splicing pathways of the CD44 pre-mRNA variable region that account for the generation of all of the CD44 isoforms described in breast tissue. An alternative splicing pathway that reflects inclusion of variable exons in a gradual 3'-to-5' fashion is evidenced in breast ductal carcinoma and its lymph node metastases. This pathway is compatible with a mechanism that generates the standard form of CD44 (devoid of variable exons) and is distinguishable from an alternative splicing pathway that involves exclusively variant exon 3 and is observable in both normal and carcinoma breast tissue. We show that both pathways are detectable in the same cell type in the breast and provide a speculative model by which these splicing routes could take place.

Benign myoepithelioma of the skin

A case of cutaneous myoepithelioma is reported. The tumor was composed of spindle-shaped, epithelioid, and plasmacytoid (hyaline) cells. It exhibited a widespread immunoreactivity for low molecular weight keratins and protein S-100, being irregularly positive for smooth muscle actin. Ultrastructural studies of tumor cells showed a variable content of intermediate filaments, with focal densities resembling smooth muscle dense bodies. A well-developed basal lamina, pinocytotic vesicles, and some desmosomes were also observed. In spite of being accepted as an individual entity, myoepitheliomas probably belong to a family of lesions that include mixed tumors. Therefore, this case can be considered as a salivary-gland-type tumor, probably originating from myoepithelial cells of sweat glands. The existence of this unique neoplasm provides further support to the debated role of myoepithelial cells in the development of mixed tumors.

Overexpression of Ki-67 and cyclins A and B1 in JC virus-infected cells of progressive multifocal leukoencephalopathy

Both SV40 and JC virus (JCV) appropriate the host cell replicative machinery to attend to their own reproductive needs. SV40 large T antigen is able to induce the expression of cyclins A, B1, and E (but not of cylin D1) in transfected diploid cells. Whether JCV infection influences cyclin expression in a similar fashion in the setting of progressive multifocal leukoencephalopathy (PML) remains unknown. Brain lesions from 7 PML cases (4 autopsies and 3 biopsies) were immunohistochemically investigated for the expression of Ki-67 and cyclins A, B1, and D1. All 7 cases showed strong positivity for Ki-67 and cyclins A and B1 in JCV-infected oligodendrocytes and astrocytes, the nuclear immunolocalization of cyclin A being in strong contrast to the cytoplasmic distribution of cyclin B1. No immunostaining for cyclin D1 was obtained in any of the 7 cases. These findings suggest that JCV infection is associated with overexpression of Ki-67 and cyclins A and B1 in PML host glial cells. Since cyclin changes in JCV-infected cells recapitulate SV40 T antigen-associated cyclin fluctuations, it appears reasonable to think that JCV T antigen shares some of the previously described capabilities of SV40 T antigen to alter cyclin expression for the sake of viral replication.

Induction of proliferating cell nuclear antigen and Ki-67 expression by cytomegalovirus infection

With the goal of facilitating viral reproduction, cytomegalovirus (CMV) induces changes in the host cell replication machinery. Very little information is available, however, on the effects brought about by CMV on proliferating cell nuclear antigen (PCNA) and Ki-67 expression in infected cells. Fifty-five paraffin-embedded tissue samples (43 gastrointestinal, 10 skin, and 2 kidney biopsies) with both histological and immunohistochemical evidence of CMV infection were investigated for PCNA and Ki-67 expression by the avidinbiotin-peroxidase method. Of the 55 cases studied, 47 were positive for PCNA and 46 for Ki-67. PCNA and Ki-67 immunostaining was more striking in CMV-immunoreactive, inclusion-free cell nuclei, whereas cell nuclei exhibiting well-developed CMV inclusions either showed a weak peripheral signal for both proliferation markers, or were completely negative. Enhanced PCNA and Ki-67 expression appears to be among the changes induced by CMV infection in host cells. Moreover, this induction seems to reach its peak during the earlier phases of CMV infection and abate as the infection proceeds to its inclusion-forming phases, when a sufficiently high viral load would have been attained.

expression patterns of cyclins D1 and E in condyloma acuminatum in comparison with psoriatic proliferative lesions

Human papillomavirus (HPV) is able to subvert the host cell replication machinery so as to foster viral reproduction. Specifically, HPV infection is known to induce expression of proliferation antigens such as Ki67 and proliferative cell nuclear antigen (PCNA) in differentiated keratinocytes which have ceased to replicate. In order to determine whether cyclin D1 or cyclin E deregulation is also a feature of HPV infection, an immunohistochemical investigation of cyclin D1, cyclin E, Ki67, and PCNA expression has been carried out in 38 cases of HPV 6/11-related condyloma acuminatum (CA). Results were compared with those obtained from 15 psoriatic proliferative lesions. Whereas 35 (92.1 per cent) CA samples exhibited positive nuclear immunostaining for cyclin E, no cyclin D1 immunoreaction was detected in any of the CA samples studied. All psoriatic lesions showed immunostaining for both cyclins. All CA cases revealed a positive immunoreaction for Ki67 and 33 for PCNA, both in the parabasal and in the differentiated upper epithelial layers. Parabasal keratinocytes of psoriatic lesions were always positive for both Ki67 and PCNA. These results indicate that in the onslaught of HPV 6/11 upon the keratinocyte replication machinery, cyclin E, PCNA, and Ki67 are amongst the targeted cell cycle modulators, whereas cyclin D1 is spared the main effects of virus-cell interplay. In contrast, both cyclins seem to be induced in psoriasis, a non-viral proliferative skin condition.

Reduced survival in patients with stage-I non-small-cell lung cancer associated with DNA-replication errors

To better understand whether replication-error-type instability (RER+) is a frequent genetic alteration event in surgical-pathologic stage-I non-small-cell lung cancer (NSCLC) and identify whether it constitutes an independent prognostic parameter, we examined 35 surgical-pathologic stage-I-NSCLC patients with complete follow-up in all cases for at least 49 months. The tumor samples and the paired histopathologically normal lung samples for each patient were analyzed for 8 microsatellite markers located at chromosomes 3p and 2p to investigate microsatellite alterations such as RER+ and loss of heterozygosity (LOH). Single-strand-conformation-polymorphism analysis for detection of p53 and k-ras gene mutations was also carried out. Genetic data were correlated with clinical outcome and histopathologically established prognostic factors. RER+ at one or both chromosomes was identified in 24 of the 35 patients; 9 patients showed LOH. A statistically significant correlation was found between RER+ and poor prognosis (p = 0.001). Furthermore, RER+ proved to be an independent factor that predicted decreased survival, ranking first, followed by visceral pleural invasion. A trend towards worse survival was strongest in the group of patients with tumor size greater than 3 cm (T2). Patients with other genetic abnormalities, such as K-ras mutations, p53 mutations or LOH, had prognoses similar to those of patients without such aberrations. The data suggest that RER+ is common in NSCLC, that it may provide important prognostic information in stage-I NSCLC and serve as a useful marker for relapse-risk assessment in operable NSCLC patients.

Microsatellite alterations at 5q21, 11p13, and 11p15.5 do not predict survival in non-small cell lung cancer

We investigated the clinical implications of allelic deletions at three common sites of loss of heterozygosity (LOH) in regions 5q21, 11p15.5, and 11p13 in 86 patients with non-small cell lung cancer (NSCLC). We performed a PCR-based microsatellite polymorphism assay for detection of LOH. The microsatellite markers used were D5S82 (proximal to the APC gene), MCC (within the MCC gene), D11S904 (11p13), HRAS (within the H-ras gene), and D11S860 (11p15.5). Of the 68 informative cases at 5q21 loci, LOH was found in 14 cases (20%), whereas LOH frequency in 11p15.5 and 11p13 was 31% (19 of 61 informative cases) and 19% (12 of 63 informative cases), respectively. There was a significant correlation between 5q21 LOH and mediastinal lymph node involvement (P = 0.03). However, no differences were observed in median survival times (26 months in patients with 5q21 LOH versus 37 months in the remainder; P = 0.33) nor in patients with 11p LOH (38 months versus 32 months, respectively; P = 0.72). Cox's proportional hazards model predicted that stage was the only independent poor prognostic marker in the entire cohort of NSCLC patients. Thus, the present study revealed two important abnormalities, LOH at chromosome 5q21 and LOH at chromosome 11p, both implied in NSCLC development.

Reduced survival in patients with stage-I non-small-cell lung cancer associated with DNA-replication errors

To better understand whether replication-error-type instability (RER+) is a frequent genetic alteration event in surgical-pathologic stage-I non-small-cell lung cancer (NSCLC) and identify whether it constitutes an independent prognostic parameter, we examined 35 surgical-pathologic stage-I-NSCLC patients with complete follow-up in all cases for at least 49 months. The tumor samples and the paired histopathologically normal lung samples for each patient were analyzed for 8 microsatellite markers located at chromosomes 3p and 2p to investigate microsatellite alterations such as RER+ and loss of heterozygosity (LOH). Single-strand-conformation-polymorphism analysis for detection of p53 and k-ras gene mutations was also carried out. Genetic data were correlated with clinical outcome and histopathologically established prognostic factors. RER+ at one or both chromosomes was identified in 24 of the 35 patients; 9 patients showed LOH. A statistically significant correlation was found between RER+ and poor prognosis (p = 0.001). Furthermore, RER+ proved to be an independent factor that predicted decreased survival, ranking first, followed by visceral pleural invasion. A trend towards worse survival was strongest in the group of patients with tumor size greater than 3 cm (T2). Patients with other genetic abnormalities, such as K-ras mutations, p53 mutations or LOH, had prognoses similar to those of patients without such aberrations. The data suggest that RER+ is common in NSCLC, that it may provide important prognostic information in stage-I NSCLC and serve as a useful marker for relapse-risk assessment in operable NSCLC patients.

Cyclin D1 overexpression in non-small cell lung carcinoma: correlation with Ki67 labelling index and poor cytoplasmic differentiation

Cyclin D1 is part of the molecular system regulating the cell cycle G1 to S transition point. Its overexpression, a common finding in carcinomas of the breast, oesophagus, and head and neck, has also been demonstrated in a high percentage of non-small cell lung carcinomas (NSCLCs). The role of cyclin D1 in NSCLC has been studied by correlating its immunoreactivity with the Ki67 labelling index in paraffin-embedded, autoclaved surgical samples of 56 NSCLC cases. In addition, flow cytometric determination of ploidy and cell cycle status was carried out on 172 fresh tumour samples from the same cases. Twenty-four (42.8 per cent) NSCLCs showed positive cyclin D1 immunostaining, a finding which showed no relationship to ploidy pattern, cell cycle phase, histological subtype, or lymph node metastasis, but was significantly associated with the Ki67 labelling index (P = 0.03) and with poor cytoplasmic differentiation (P = 0.01). Cyclin D1-positive nuclei were abundant in poorly differentiated zones and absent in the best differentiated areas, particularly in heavily keratinized fields. These data indicate that in NSCLC, cyclin D1 overexpression is not only associated with a high cell proliferation rate, but also seems to play a role in the process of tumour differentiation.

Cyclin D1 overexpression in non-small cell lung carcinoma: correlation with Ki67 labelling index and poor cytoplasmic differentiation

Cyclin D1 is part of the molecular system regulating the cell cycle G1 to S transition point. Its overexpression, a common finding in carcinomas of the breast, oesophagus, and head and neck, has also been demonstrated in a high percentage of non-small cell lung carcinomas (NSCLCs). The role of cyclin D1 in NSCLC has been studied by correlating its immunoreactivity with the Ki67 labelling index in paraffin-embedded, autoclaved surgical samples of 56 NSCLC cases. In addition, flow cytometric determination of ploidy and cell cycle status was carried out on 172 fresh tumour samples from the same cases. Twenty-four (42.8 per cent) NSCLCs showed positive cyclin D1 immunostaining, a finding which showed no relationship to ploidy pattern, cell cycle phase, histological subtype, or lymph node metastasis, but was significantly associated with the Ki67 labelling index (P = 0.03) and with poor cytoplasmic differentiation (P = 0.01). Cyclin D1-positive nuclei were abundant in poorly differentiated zones and absent in the best differentiated areas, particularly in heavily keratinized fields. These data indicate that in NSCLC, cyclin D1 overexpression is not only associated with a high cell proliferation rate, but also seems to play a role in the process of tumour differentiation.

Gastrointestinal autonomic nerve tumor: further observations regarding an ultrastructural and immunohistochemical analysis of six cases

Gastrointestinal autonomic nerve tumor (GANT) is a specialized form of stromal neoplasm whose ultrastructural features support a myenteric plexus derivation and provide the basis for its diagnosis. GANT actual frequency, relationship to skeinoid fibers, and CD34 expression status are some of the controversial aspects of this entity. Out of 14 gastrointestinal stromal tumors gathered during a 1-year period, six (42%) instances were diagnosed as GANT by electron microscopic study of at least five ultrathin sections per case. Additionally, GANTs were immunohistochemically investigated with a panel of nine antibodies including CD34. Ultrastructurally, every GANT case showed diagnostic findings and evidence of skeinoid fibers, whereas immunohistochemically all except one were CD34 positive. Immunoreactivity for neuron-specific enolase, synaptophysin, and vimentin was a common occurrence as well. In conclusion, GANT seems to be more frequent than hitherto recognized, skenoid fibers are a regular feature of GANT, and a positive CD34 immunoreaction does not discriminate between GANT and other non-smooth muscle, non-schwannian neoplasms.

Differential expression of CD44v6 in adenocarcinoma of the pancreas: an immunohistochemical study

Alternative splicing gives rise to numerous CD44 isoforms, some of which seem to have a role in tumour metastasis. Specifically, a variant form of CD44 with sequences encoded by exon v6 (CD44v6) confers metastatic potential when transfected into a nonmetastasizing cell line of rat pancreatic adenocarcinoma. This study has investigated standard CD44 (CD44s) and CD44v6 expression immunohistochemically in 6 samples of normal pancreatic tissue, 4 of tissue affected by chronic pancreatitis, and 24 of tissue from metastasizing and nonmetastasizing pancreatic adenocarcinomas. In addition, 18 samples from lymph node or visceral metastases were included in the study. CD44s was expressed in nonneoplastic tissue and in tissue from pancreatic adenocarcinomas. In contrast, CD44v6 was not detected in any of the normal tissue or chronic pancreatitis specimens, whereas 54% of pancreatic adenocarcinomas and 55% of metastases expressed this variant exon. Although it is not clear whether CD44 isoforms containing exon v6 play a part in malignant progression in the human exocrine pancreas, it seems plausible that the expression of multiple isoforms containing this and other variant exon confers a selective advantage on pancreatic adenocarcinoma.

DNA amplification in glial cells of progressive multifocal leukoencephalopathy: an image analysis study

JC virus (JCV), the agent of progressive multifocal leukoencephalopathy (PML), has been shown by both immunohistochemistry and flow cytometry to be associated with p53 protein stabilization. Since stabilization/inactivation of p53 is associated with the development of genomic instability, abnormal cell DNA contents are to be expected in JCV-infected cells of PML. This work explores that possibility by image analysis evaluation of DNA content in PML-infected oligodendrocytes and bizarre astrocytes. Brain paraffin sections of PML lesions from five adult male patients with the acquired immune deficiency syndrome (AIDS) were treated with the Feulgen technique to obtain a stochiometric staining of DNA and analyzed with a microscope image processor. Inclusion-bearing oligodendrocytes exhibited near tetraploid DNA indices in each of the five cases, whereas atypical astrocytes were in the hypertetraploid range in all cases and were polyploid in four instances. This evidence of DNA amplification in PML glial cells is congruent with the functional abolition of p53 protein in association with JCV infection and lends further support to the role of p53 as a keeper of diploid status and guardian of genomic stability.

Accumulation of wild-type p53 protein in progressive multifocal leukoencephalopathy: a flow of cytometry and DNA sequencing study

p52 protein accumulation in JC virus (JCV)-infected cells of progressive multifocal leukoencephalopathy (PML) has been previously shown. Since many viral proteins are known to bind and stabilize p53, we are addressing the question of whether p53 protein accumulation in PML is the result of its sequestration by JCV and not the outcome of a p53 gene mutation which would prolong its half-life. We have investigated the status of the p53 gene in frozen autopsy brain samples from five PML patients. After isolating genomic DNA, p53 gene exons 2 through 9 were amplified and sequenced. No discrepancies were found in the DNA sequences of exons 2 through 9 and their intron/exon barriers when compared to those published for wild-type p53. On the other hand, dual (p53/DNA) flow cytometry analysis revealed p53 expression above that of the isotypic controls for each case. No aneuploid populations could be identified, however, which seems at odds with the aneuploid status normally associated with mutation-induced p53 dysfunction. These results indicate that the p53 gene harbors no mutations in PML and provide further evidence of p53 protein accumulation in this condition. Since p53 protein buildup in JCV-infected cells is not the consequence of a mutagenic interaction between JCV and the cell genome, we propose instead that p53 accumulation results from its binding and stabilization by JCV T protein.

Standard and variant CD44 isoforms are commonly expressed in lung cancer of the non-small cell type but not of the small cell type

Cluster of differentiation 44 (CD44) encompasses a polymorphic family of cell membrane glycoproteins involved in the mechanism of tumour invasion and metastasis. Since non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC) display very different rates of progression, a significant discrepancy in their CD44 expression profiles is to be expected. An immunohistochemical study was undertaken on the expression of standard CD44 (CD44s) and the variant isoforms containing the domains encoded by variant exon 3 (CD44v3) or variant exon 6 (CD44v6) in paraffin-embedded bronchial biopsy specimens from 32 NSCLC cases and 11 SCLC cases. An absolute lack of immunoreactivity for CD44s, CD44v3, and CD44v6 was obtained in every case of SCLC, whereas 28 of the 32 NSCLC cases showed a positive immunoreaction for at least one of the three epitopes investigated. In conclusion, the occurrence of standard and variant CD44 isoforms in NSCLC and their absence in SCLC suggest the possibility that CD44 is in some way instrumental in conditioning the biological behaviour of NSCLC, but not of SCLC, whose metastatic cascade would be set in motion by the activation of hitherto unidentified, CD44-independent pathways.

Role of CD44 in the invasiveness of glioblastoma multiforme and the noninvasiveness of meningioma: an immunohistochemistry study

CD44 is a polymorphic family of cell adhesion molecules that seems to be instrumental in the mechanism of tumor invasion and metastasis. Tumor cell expression of CD44, or lack thereof, may be one of the factors conditioning the highly disparate ability to penetrate the brain extracellular matrix (ECM) exhibited by glioblastoma multiforme (GM) and conventional meningioma. To assess the presence of CD44 in these two tumor types we have immunohistochemically investigated the expression of CD44 standard form (CD44s) and the variant isoforms containing the domain encoded by variant exon 3 (CD44v3) and variant exon 6 (CD44v6) in paraffin-embedded tissue from 10 conventional meningiomas and 10 GMs. A CD44s-/CD44v-phenotype was discerned in the meningioma cases, whereas GMs featured a CD44s+/CD44v- expression profile. Consequently, the growth patterns of meningioma and GM seem to be, at least in part, a reflection of their CD44 expression status. Paucity of CD44 in meningioma cells would render them unable to infiltrate the brain ECM, whereas CD44-rich glioma cells would successfully migrate through it. Conversely, lack of CD44v expression would contribute to explain the lack of metastatic potential characterizing both conventional meningioma and GM.

Desmin myopathy: a multisystem disorder involving skeletal, cardiac, and smooth muscle

Myopathy associated with desmin-type intermediate filaments is an uncommon disorder of skeletal and/or cardiac muscle. The present study focuses on a 28-year-old man with generalized muscular atrophy, cardiomyopathy, and intestinal malabsorption and pseudo-obstruction. Abundant sarcoplasmic granular and filamentous aggregates that were ultrastructurally continuous with Z lines or dense bodies and exhibited intense immunostaining for desmin were present throughout the skeletal musculature, myocardium, and smooth muscle of the intestine. Moreover, neurofilament-immunoreactive axonal spheroids were identified in the spinal cord and roots. These widely distributed findings illustrate the multisystemic character of desmin myopathy, which in this instance first adds intestinal smooth muscle involvement to its already known skeletal and cardiac muscle manifestations. The additional presence of neurofilament aggregates in the spinal cord and roots constitutes an extremely rare conjunction of intermediate filament pathology of the neuromuscular system.

Pigmented epidermotropic ductal carcinoma of the breast in a male. Ultrastructural evidence of melanocytic colonization and melanin transfer to the tumor

The first case of pigmented epidermotropic breast carcinoma in a male, presenting as a pigmented lesion of the areola and nipple, is described. Immunohistochemical and ultrastructural studies demonstrated that the pigmentation was found to be primarily due to colonization of tumor nests by melanocytes, with numerous melanophages interspersed in the desmoplastic stroma and only occasional compound melanosomes within the epithelial tumor cells.

Giant cell myocarditis: monocytic immunophenotype of giant cells in a case associated with ulcerative colitis

Giant cell myocarditis (GCM) is a rare condition whose histologic hallmark, the multinucleate giant cell, is of debated origin (monocytic v myogenic). We report the case of a 46-year-old woman with a previous diagnosis of ulcerative colitis who rapidly deteriorated and died as the result of refractory ventricular tachyarrhythmias. Postmortem examination showed a diffuse infiltration of the myocardium by round cells and multinucleate giant cells. Immunohistochemically, round cells were demonstrated to be T lymphocytes admixed with monocytes. Multinucleate giant cells expressed monocytic markers (MAC 387, lysozyme) and were negative for muscle markers (actin, desmin, myoglobin). This case illustrates the monocytic and macrophagic nature of multinucleate giant cells and lends support to the autoimmune hypothesis of GCM by the concurrence of the latter with ulcerative colitis.

p53 immunoreactivity in hepatocellular adenoma, focal nodular hyperplasia, cirrhosis and hepatocellular carcinoma

The prolonged half-life of mutant p53 makes feasible its immunocytochemical detection. In order to assess the pathogenetic role of mutant p53 in regenerative and neoplastic liver disease we studied its immunohistochemical expression in cases of hepatic cirrhosis, hepatocellular carcinoma (HCC), cirrhosis with areas of HCC, hepatocellular adenoma and focal nodular hyperplasia. The study included needle and wedge biopsies of 50 cirrhotic livers, 59 HCCs (36 of them with associated cirrhosis), six adenomas and two focal nodular hyperplasias. Sixty-five HCC fine-needle cytology specimens were also included in the study. There was no immunohistochemical evidence of mutant p53 expression in any of the cases of cirrhotic liver (except for one instance associated with HCC) adenoma or focal nodular hyperplasia. In contrast p53 was detected in 8.5% of HCC cases in the biopsy series and 24% of HCC cases in the fine needle aspiration series. In addition, mutant p53 expression in HCC was positively correlated with tumour grade. According to grade, the distribution of p53 positive immunoreactivity among HCCs was as follows: Grade I-II, 0% of cases in the biopsy series and 9% in the fine needle aspirates; Grade III, 18% in the biopsy series and 55% in the fine needle aspirates; and Grade IV, 40% in the biopsy series. Therefore, mutant p53 expression does not seem to be associated with benign liver lesions but seems to correlate with the progression of HCC through various grades of increasing malignancy.

p53 and proliferating cell nuclear antigen expression in JC virus-infected cells of progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML), a demyelinating disease of the central nervous system (CNS) caused by infection with JC papova virus (JCV), is characterized by marked atypical changes in the glial cells. The JCV T protein binds cellular p53 (a tumor suppressor gene product), which as a result loses its normal down regulating influence on the cell cycle. We hypothesized that this binding would stabilize p53 and prolong its half life, leading to its immunohistochemical detection. To prove our theory combined JCV DNA:DNA in situ hybridization (ISH) and glial fibrillary acidic protein (GFAP) immunohistochemistry (IHC) as well as p53/GFAP double IHC were performed on routinely processed sections of five brains obtained at autopsy and two cerebral biopsy specimens from seven patients with PML. All specimens showed JCV infected oligodendrocytes and bizarre looking astrocytes that immunostained strongly for p53. In addition, because loss of p53 function results in proliferating cell nuclear antigen (PCNA) overexpression PCNA/GFAP double IHC was carried out, and a positive immunoreaction was obtained in JCV infected cells in the two biopsy specimens. The evidence of p53 immunoreactivity in JCV harboring glial cells seems to indicate a link between the JCV induced stabilization/inactivation of p53 and the striking tumorlike glial changes seen in PML. Proliferating cell nuclear antigen overexpression in these cells further supports this pathogenetic construct.

Proliferating cell nuclear antigen expression in normal, regenerative, and neoplastic liver: a fine-needle aspiration cytology and biopsy study

Information about a tissue's proliferative activity can be obtained from the immunocytochemical investigation of proliferating cell nuclear antigen (PCNA), an auxiliary protein of DNA polymerase delta expressed by cycling cells. To determine whether a relationship exists between morphology and PCNA expression in normal, regenerative, and malignant neoplastic hepatocytes, this study was undertaken on 48 fine-needle aspiration cytology (FNAC) cell blocks from eight normal livers, eight cirrhotic livers, and 32 hepatocellular carcinomas (HCCs), as well as on 41 needle or wedge biopsy specimens from 10 normal livers, 13 cirrhotic livers, one focal nodular hyperplastic liver, and 17 HCCs. Anti-PCNA monoclonal antibody PC10 was applied to formalin-fixed, paraffin-embedded tissue using the avidin-biotin method. Proliferating cell nuclear antigen immunoreactivity was evaluated as follows: absent; minimal, less than 5% positive nuclei; grade 1, 5% to 25% positive nuclei; grade 2, 26% to 50% positive nuclei; grade 3, 51% to 75% positive nuclei; and grade 4, 76% to 100% positive nuclei. In both the FNAC and biopsy series normal and regenerative livers were either completely negative or minimally immunoreactive (under 5% positive nuclei). In contrast, all well-differentiated HCC cases exhibited over 15% positive nuclei. Most well-differentiated HCCs were grade 1 (85.7% in the FNAC series and 76.92% in the biopsy series) and the majority of moderately differentiated HCCs were grade 3 (63.63% in the FNAC series, but only 50% in the biopsy series). Therefore, absent or minimal PCNA immunoreactivity seems to be a useful adjuvant to discriminate normal/regenerative liver from HCC, whose degree of differentiation tends to correlate with the level of PCNA expression. These observations apply to both the FNAC and biopsy series, which yielded very similar data.

Six new cases of prolymphocytic leukemia with heterogeneous prognosis. Clinical and immunologic features, light microscopy, and ultrastructural findings

The clinical features and diagnostic evaluation of six patients affected by prolymphocytic leukemia (PLL), are described. Some of the cases deviate from a relatively uniform and aggressive clinical course of the disease entity. An actuarial survival analysis of 60 cases gathered from the literature and the authors' experience indicate that the cases showing the most prolongated evolution may reach 30% of the total. The different aggressiveness in the clinical course of these patients does not depend on the efficiency of the therapies applied. The percentage of prolymphocytes (PL) in peripheral blood throughout the clinical course was variable and not depending on the treatments used. This fact, in conjunction with (1) the presence of cellular types deviated from the typical PL and detected both at optical and ultrastructural levels and (2) the existence of cases of PL with minimal splenomegaly and leukocyte counts of less than 50 X 10(9)/liter, could lead to an underdiagnosis of PLL and hinder the actual cognition of the natural medical history of the disease.

On the histogenesis of Ewing's sarcoma. An ultrastructural, immunohistochemical, and cytochemical study

Forty-two cases of Ewing's sarcoma (ES) have been studied with light microscopy during the 9-year period 1974 to 1982. Thirty-three patients had ES of bone, and in 9 patients the tumor was located in the extraskeletal soft tissues. Cases which fulfilled all the morphologic criteria were accepted as typical ES (31 cases), and those with some architectural or cytologic peculiarities were considered atypical forms of ES (11 cases). An immunohistochemical study (PAP method) to evaluate the presence in the tumor cells of the following markers: myoglobin, F-VIII-related antigen, lysozyme, alpha-1-antitrypsin, alpha-1-antichymotrypsin, and immunoglobulins (IgG, IgA, IgM, kappa and lambda light chains), was performed with negative results in all cases (paraffin blocks were available in 38 cases). The cytochemical study on fresh tissue imprints from five patients (PAS, Sudan Black, alpha-naphthyl acetate esterase, acid phosphatase, beta glucuronidase, myeloperoxidases, naphthol-AS-D chloroacetate esterase and alkaline phosphatase) gave no pattern of histogenetic significance, PAS being the best morphologic marker in tissue sections and touch preparations. A detailed ultrastructural study was performed on 34 cases; the main findings may be summarized as follows: medium sized cells, polygonal shape, oval nuclei, smooth nuclear envelope, abundant euchromatin, well-developed nucleolonema, scant membranous organelles, abundant hyaloplasmic glycogen, occasional lipid vacuoles, straight cell membranes, and primitive intercellular junctions. No differences were found between bone and extraskeletal ES; moreover, typical and atypical forms showed moderate quantitative differences with no qualitative change. The histogenesis is discussed; no functional or morphologic markers have been found to suggest the cell of origin; however, some cell lines may be excluded. It is the impression of the authors that they are dealing with a primitive noncommitted mesenchymal cell.

Pathology of the kidney in "toxic oil epidemic syndrome"

In May 1981, a massive intoxication of people who had ingested adulterated cooking oil took place in Madrid and nearby provinces. Although the patients presented, in the first phase of the disease, with acute respiratory illness, later on thromboembolic complications, severe neuromuscular involvement, and scleroderma-like cutaneous lesions appeared. Kidneys were apparently spared; however, 4 out of 842 admitted patients developed glomerulonephritis; kidney biopsies revealed glomerular, vascular, tubular, and interstitial changes. Cases 1 and 3 had diffuse proliferative endocapillary glomerulonephritis; case 2 had diffuse membranoproliferative glomerulonephritis; and case 4 had diffuse extracapillary glomerulonephritis. Three cases had vascular lesions characterized by degenerative and proliferative endothelial changes, intimal foamy macrophages, and partial or complete obliteration of the vascular lumen by concentric myxoid fibrosis. There were signs of necrosis of tubular epithelium along with edema and lymphocytic and eosinophilic interstitial infiltration. Two out of 22 autopsies had segmentary glomerulonephritis, and 17 out of 22 autopsies showed renal vascular lesions.

Inclusion body myofibroblasts other than those seen in recurring digital fibroma of childhood

Four patients of the toxic oil epidemic syndrome (TOES), which took place in Spain in 1981, showed a dermohypodermal fibroblastic process with round eosinophilic cytoplasmic inclusions (ECI) in the proliferating cells. Light and electron microscopic studies revealed that those cells had myofibroblastic features and that the ECI were identical to those seen in recurring digital fibroma of childhood (RDFC). Two cases of RDFC, involving the fingers of 6-month-old and 2-year-old patients, were examined by light and electron microscopy for comparative study. The 4 patients of TOES, aged 14 to 46 years, showed generalized sclerodermalike skin changes, and skin biopsies were obtained from the anterior wall of the abdomen and retromaleolar region of the left leg. The ultrastructural study of the ECI and the initiating changes leading to them allowed us to suggest a cytoskeletal origin for these inclusions.

Signet-ring cell lymphoma. Ultrastructural and immunohistochemical features of three varieties

An ultrastructural and immunohistochemical study was performed on three malignant lymphomas of follicular center cell origin with signet-ring cells. The first case corresponded to a diffuse lymphoma with follicular center cells and plasmacytic features; the other two cases corresponded to the nodular centrocytic-centroblastic category. The neoplastic lymphocytes contained Russell bodylike inclusions, clear vacuoles, and ill-defined eosinophilic masses, respectively, which produced a displacement of the nuclei to the periphery. Ultrastructurally, there were three different morphologic types because of the following cytoplasmic changes: the accumulation of electron-dense granular material in the cisternae of the rough endoplasmic reticulum; the formation of clear vacuoles with a smooth limiting membrane; and, the presence of granular-fibrillar and crystalline material in the hyaloplasm without a limiting membrane. The first type of signet-ring cell contained monoclonal immunoglobulin (IgM-K). No immunoglobulins were found in the clear cytoplasmic vacuoles of the second type; however, the rim of cytoplasm stained for IgG, kappa and lambda. Finally, the third type showed IgG and kappa light chain in the hyaloplasmic inclusions. It is concluded that the signet-ring cell appearance is due to an abnormal production and secretion of immunoglobulins.

Ultrastructural diagnosis of facial nerve schwannoma using fine needle aspiration

In a 14-year-old boy presenting with left facial nerve paralysis, physical examination revealed a soft, round mass in the floor of the left external auditory canal. A fine needle aspiration biopsy was performed to obtain material for light and electron microscopy. Several small groups of uniform, spindle-shaped neoplastic cells were present on the slides; a malignant mesenchymal tumor was considered, but a definite diagnosis could not be established under light microscopy. The ultrastructural examination revealed spindle-shaped and stellate cells with multiple parallel cytoplasmic processes lined with a well-developed basal lamina; these features are highly characteristic of a benign schwannoma.

Inflammatory fibroid polyps of the gastrointestinal tract. An immunohistochemical and electron microscopic study

Seven cases of inflammatory fibroid polyp (IFP) are studied, two of them with electron microscopy. The morphologic findings suggest a myofibroblastic origin for the proliferating cells. Other histogenetic hypothesis which propose a neural or vascular nature for this lesion are ruled out. The ultrastructural features of the proliferating cells are different from schwann and endothelial cell tumors. Moreover, the immunohistochemical technique to detect Factor VIII related antigen was negative in the intercapillary cells of the seven cases. Our conclusion is that inflammatory fibroid polyp of the gastrointestinal tract represent a reactive lesion of myofibroblastic nature.

Inflammatory fibroid polyps of the gastrointestinal tract. An immunohistochemical and electron microscopic study

Seven cases of inflammatory fibroid polyp (IFP) are studied, two of them with electron microscopy. The morphologic findings suggest a myofibroblastic origin for the proliferating cells. Other histogenetic hypothesis which propose a neural or vascular nature for this lesion are ruled out. The ultrastructural features of the proliferating cells are different from schwann and endothelial cell tumors. Moreover, the immunohistochemical technique to detect Factor VIII related antigen was negative in the intercapillary cells of the seven cases. Our conclusion is that inflammatory fibroid polyp of the gastrointestinal tract represent a reactive lesion of myofibroblastic nature.

Inflammatory fibroid polyps of the gastrointestinal tract. An immunohistochemical and electron microscopic study

Seven cases of inflammatory fibroid polyp (IFP) are studied, two of them with electron microscopy. The morphologic findings suggest a myofibroblastic origin for the proliferating cells. Other histogenetic hypothesis which propose a neural or vascular nature for this lesion are ruled out. The ultrastructural features of the proliferating cells are different from schwann and endothelial cell tumors. Moreover, the immunohistochemical technique to detect Factor VIII related antigen was negative in the intercapillary cells of the seven cases. Our conclusion is that inflammatory fibroid polyp of the gastrointestinal tract represent a reactive lesion of myofibroblastic nature.

The fibromatoses. An ultrastructural study of 31 cases

During a five year period, thirty one cases of fibromatoses were studied with electron microscopy. A special survey was performed in relation with the proliferating cell, the extracellular space and the morphologic features of some peculiar entities as: juvenile aponeurotic fibroma, nasopharyngeal angiofibroma, recurring digital fibroma of infancy and the group of proliferative fasciitis-myositis. The main conclusions drawn of this study are: the myofibroblast is the proliferating cell of these lesions; those cells are actively synthesizing native and fibrous long spacing collagen; there are frequent intracytoplasmic inclusions of fibrous long spacing collagen; the cytoplasmic inclusions of recurring digital fibroma of infancy correspond to modifications of the cytoskeleton; and, the ganglion-like cells of proliferative fasciitis-myositis are modified myofibroblasts.

The ultrastructure of conventional, parosteal, and periosteal osteosarcomas

Twenty-seven osteosarcomas of bone were examined by electron microscopy. Eighteen cases were conventional osteosarcomas, one case was an osteosarcoma that developed in Paget's disease of bone, two cases were metastasis to the lungs of conventional osteosarcomas, five were parosteal osteosarcomas (and the recurrence of one of them), and one was periosteal osteosarcoma. In addition to the basic neoplastic cell, the osteoblast-like tumor cell, seven tumor cell types could be differentiated in varying numbers in the 27 cases examined: (1) chondroblast-like; (2) fibroblast-like; (3) histiocyte-like; (4) myofibroblast; (5) osteoclast-like; (6) malignant multinucleated osteoblast-like; and (7) atypical primitive mesenchymal cells. Moreover, endothelial cells and pericytes were also present. The tumor cells showed common neoplastic features in relation with general cell configuration and fine structures. No cytoplasmic organelle was considered to be cell-specific, and only the amount and distribution of the organelles allowed us to differentiate the above mentioned cell types. The presence of malignant appearing tumor cells with abundant and dilated cisternae of RER, in an intercellular matrix containing collagen fibers with areas of focal collections or puffs of hydroxyapatite crystals, are the most characteristic ultrastructural features of osteosarcoma. However, those features are not pathognomonic and do not allow in all cases the differential diagnosis with osteoid-osteoma and benign osteoblastoma. Fields of chondroblastic, fibroblastic, or fibrohitiocytic character are indistinguishable of chondrosarcomas, fibrosarcomas, or malignant fibrous histiocytoma of bone, respectively. The comparative study of parosteal and conventional osteosarcomas revealed a marked difference in the cell population: fibroblast-like cells and myofibroblasts were the main cell types in parosteal osteosarcoma; on the contrary, myofibroblasts were very scarce or absent in conventional osteosarcomas. This difference may correlate with the better outcome of parosteal osteosarcoma. The ultrastructural features of a periosteal osteosarcoma are reported for the first time. The tumor was comprised mostly of chondroblast-like tumor cells. However, in the more cellular peripheric areas of the neoplasm, the cells were predominantly of the fibroblast-like type and showed anaplastic features.

Ultrastructural study of conventional chondrosarcomas and myxoid- and mesenchymal-chondrosarcomas

Five cases of conventional chondrosarcomas (CS.) of graded malignancy, 3 cases of myxoid CS. and 2 cases of mesenchymal CS. were studied by electron-microscopy. The chondrocyte like tumor cells of conventional CS. were characterized by: an ovoid shape, eccentric nucleus, abundant endoplasmic reticulum with dilated cisternae of RER; cytoplasmic glycogen, lipid droplets, and filaments plus numerous thin cytoplasmic projections. The histologically high grade tumors showed fewer cytoplasmic organelles, bizarre nuclei and more prominent nucleoli than the better differentiated ones. The tumor cells of myxoid CS. were chiefly fusiform. The cells frequently presented a pattern of rows with good cellular cohesion, and scanty cytoplasmic projections. The most prominent cytoplasmic feature was a conspicuous RER. Abundant cytoplasmic filaments and cytoplasmic glycogen were also observed. The undifferentiated areas of the mesenchymal CS. showed primitive mesenchymal cells with rounded nuclei, and scanty cytoplasm which was poor in organelles and glycogen. The cytoplasmic membranes were very cohesive and cytoplasmic projections were not present. Scanty cytoplasmic filaments and conspicuous desmosome like junctions were observed. The intercellular matrix of conventional and myxoid CS. consisted of fibrils, glycosaminoglycan granules and collagen fibers. In the undifferentiated zones of the mesenchymal CS. the intercellular matrix was very scanty and did not contain collagen fibrils. The more immature cells correspond to the small undifferentiated cells of mesenchymal chondrosarcoma.

Pathology of a new toxic syndrome caused by ingestion of adulterated oil in Spain

The Toxic Syndrome (TS) caused by ingestion of adulterated rapeseed oil in Spain is a new disease of multisystemic character whose aetiology and pathogenesis remains unknown. The most prominent pathological feature is a peculiar non-necrotizing vasculitis, that affects mainly the intima and involves vessels of every type and size in practically every organ. The TS begins with an acute clinical picture with pleuropneumopathy, fever, headaches, exanthems and eosinophilia. In these early clinical phases the main pathological findings were observed in the lungs and consisted of intense pulmonary interstitial oedema with scanty inflammatory mononuclear infiltrates. Ultrastructural study revealed hydropic degeneration of pneumocytes types I and II with desquamation of type I. The patients in this phase died of respiratory failure, later deaths were due to thromboembolic complications. Later still the patients developed a neuromuscular syndrome, sclerodermiform skin lesions and severe weight loss and died predominantly of infectious complications and respiratory failure. The anatomopathological picture in the peripheral nerves was that of inflammatory neuropathy with a lymphocytic perineuritis that led to perineural fibrosis with secondary axonal degeneration. The muscle presented an interstitial inflammatory myopathy at first followed by a neurogenic muscular atrophy. The skin lesions in the late phases consisted in dermal or dermal and subdermal fibrosclerosis, with vasculitis of the small arteries in the lower dermis. The salivary glands and pancreas showed vasculitis and interstitial inflammation which progressed to interstitial fibrosis and parenchymal atrophy.

Malignant fibrous histiocytoma of bone. A clinico-pathological and electronmicroscopical study

The clinicopathological and ultrastructural features of seven Malignant Fibrous Histiocytomas reported to the Spanish Registry of Bone Tumors were studied. Two patients were females (20 and 60 years old) and the other five males (15, 37, 67, 38 and 17 years old). The tumors were located in the lower femur (3 cases), upper tibia, upper humerus, rib and iliac bone. The past medical history revealed previous fracture in one patient and previous radiation of the affected bone in another; in a third patient the tumor associated to a bone infarct. Microscopically all tumors presented a storiform pattern composed of neoplastic fibroblasts, histiocytes, and malignant multinucleated giant cells. There was no evidence of osteoid or bone tissue formation by the tumor cells. Five cases were studied with electronmicroscopy; the tumor cells had features of fibroblasts, myofibroblasts, histiocytes and multinucleated histiocytes. Primary and secondary lysosomes, along with lipid vacuoles were common findings in the tumor cells. The value of the electron-microscopy in the differential diagnosis of this tumor is emphasized.

IgA nephropathy: an ultrastructural study

From a series of 333 renal biopsies examined by immunofluorescence microscopy, 231 specimens corresponded to primary glomerulonephritis unassociated with systemic diseases. Of those 231 biopsies, 39 had diffuse mesangial deposits of IgA (16.8%). Thirty cases of IgA nephropathy had one to several glomeruli in the Epon-embedded tissue. All cases showed mild to moderate increase of mesangial cells and matrix. Mesangial deposits were present in all cases; subendothelial (5/30), intramembranous (3/30), and subepithelial (10/30) deposits wee also found. Occasional dense granular deposits involved the basement membrane of the capsule of Bowman (1/30) and the subendothelial region of some extraglomerular arterioles (2/30). Thinning (6/30) and splitting (4/30) of the glomerular lamina densa appeared focally in some cases.