Peripheral neuroepithelioma of the soft tissues. A retrospective analysis of fifteen pediatric patients

PURPOSE

The purpose of this study was to determine the clinical outcome for pediatric patients with peripheral neuroepithelioma treated with combined modality therapy and followed long enough to account for late relapses.

PATIENTS AND METHODS

Fifteen patients, ages 3 3/12 to 19 10/12 years, with peripheral neuroepithelioma (median follow-up 91 months) were diagnosed at The Children's Hospital, Denver, Colorado over the period 1980-1989. All of these malignancies originated in the soft tissues. A critical review of these cases was performed with particular consideration given to the site and stage of the tumor and to the radiographic findings at presentation. Thirteen patients had bulk (> 5 cm in the greatest dimension) or metastatic disease. Four patients had primary tumors involving the chest wall. All patients received chemotherapy, which included at least doxorubicin, vincristine, and cyclophosphamide. Definitive surgical resections were performed on 13 of 15 patients.

RESULTS

Five patients relapsed. Three were late relapses 24-44 months after diagnosis. Three of the five patients who relapsed had chest wall primaries. There were three deaths in this series due to peripheral neuroepithelioma and one due to sepsis. The overall survival was 68.5%, and the recurrence-free, survival 55.2%. Two patients with pulmonary relapses were treated with surgery and intensive chemotherapy and remain free of disease > 51 months following recurrence.

CONCLUSIONS

Combined treatment modalities appear to be important for optimal outcome. This series represents the first report of favorable outcome of peripheral neuroepithelioma using a series with follow-up that is long enough to account for late relapses.

The role of electron microscopy in evaluating ciliary dysfunction: report of a workshop

This report summarizes the proceedings of a workshop organized with the purpose of bringing together many of those with substantial experience in this troublesome area of pathology for an active interchange of ideas, opinions, problems, and solutions. Recognition was given the fact that current knowledge and technical capabilities are woefully inadequate for dealing with the diagnostic questions now being asked. Until such time as these inadequacies can be remedied, a very conservative approach to the interpretation of ultrastructural studies is advocated.

Renal neoplasms mimicking rhabdoid tumor of kidney. A report from the National Wilms' Tumor Study Pathology Center

Fifty-six renal neoplasms reviewed by the National Wilms' Tumor Study Pathology Center presented with histologic features that resulted in confusion with rhabdoid tumor of kidney, a usually lethal childhood renal tumor; all were eventually diagnosed as other entities. Conspicuous filamentous cytoplasmic inclusions or large nucleoli, typical findings in rhabdoid renal tumors, were the usual source of diagnostic difficulty. Most, but not all, tumors occurred in pediatric patients. Sixteen were examples of Favorable Histology Wilms' tumor, which invited confusion with rhabdoid tumors either on the basis of filamentous cytoplasmic inclusions (15 cases) or macronucleoli (one case). In most cases, foci of typical Wilms' tumor blastemal aggregation or evidence of definitive nephrogenic differentiation facilitated the correct diagnosis. All 10 patients for whom information about outcome was available were alive at last follow-up. The other 40 renal lesions mimicking rhabdoid tumor of kidney consisted of a clinically and histogenetically diverse group of neoplasms, including anaplastic Wilms' tumor, congenital mesoblastic nephroma, renal cell carcinoma, transitional cell carcinoma, collecting-duct carcinoma, oncocytoma, rhabdomyosarcoma, malignant neuroepithelial tumors, and lymphoma. Most of these lesions could be separated from renal rhabdoid tumors and correctly classified on the basis of careful attention to light microscopic details, but in several cases electron microscopy or immunocytochemical studies were helpful or essential.

Primitive pelvic sarcoma resembling clear cell sarcoma of kidney

Clear cell sarcoma of kidney (CCSK) is an aggressive childhood renal tumor of unknown histogenesis that has not been reported to occur outside the kidney. The article describes an extrarenal neoplasm arising in the pelvic soft tissues of a 13-year-old boy that was composed predominantly of uniform mesenchymal cells with optically clear cytoplasm supported by an arborizing network of small blood vessels, which was indistinguishable in appearance from CCSK. The electron microscopic findings, although nonspecific, were essentially identical to those of CCSK, with tumor cells displaying fine chromatin, electron-lucent cytoplasm, and intercellular collagen but no evidence of tissue-specific differentiation. Immunocytochemical studies showed positivity for vimentin but negative results for desmin, myoglobin, cytokeratin, epithelial membrane antigen, S-100 protein, neuron-specific enolase and factor VIII-related antigen. Tumor cells were also nonreactive with Ulex lectin. This unusual pelvic tumor and CCSK may both derive from primitive mesenchymal cells and may represent phenotypic but not necessarily histogenetic analogs.

Lipid-rich rhabdomyosarcoma--a potential source of diagnostic confusion

Rhabdomyosarcoma is an often primitive tumor capable of diverse morphologic manifestations. The article describes three cases of childhood rhabdomyosarcoma in which a significant population of lipid-rich tumor cells was present. The lack of specificity and potentially confusing nature of this feature are discussed, and the ultrastructural diagnosis of rhabdomyosarcoma is briefly reviewed.

Benign nodal lesions mimicking metastases from pediatric renal neoplasms: a report of the National Wilms' Tumor Study Pathology Center

Regional lymph node status is a key factor in the staging of pediatric renal tumors on the National Wilms' Tumor Study (NWTS). A review of cases entered on the NWTS has uncovered a number of cases where benign lymph node findings were mistaken for metastases. Most frequently, this was due to the presence of complexes of epithelial cells and Tamm-Horsfall protein within nodal sinuses. The epithelial cells were derived from damaged nephrons, usually resulting from obstruction by tumor. Another epithelial pseudometastic lesion, intranodal squamous epithelial cells, was found to originate from metaplastic calyceal urothelium. Benign mesothelial or coelomic inclusions similar to those previously described in pelvic and periaortic lymph nodes of adult females were found in nodes of four patients, including two boys, who are, to our knowledge, the first to be described with this finding. Other sources of confusion included protrusion of lymphoid follicles or germinal centers into nodal sinuses, thick endothelial cells of postcapillary venules mimicking epithelial tubules, nodal megakaryocytes resembling anaplastic nuclear changes, and histiocytic granulomas. Immunocytochemical methods were useful in evaluating some of these phenomena. Recognition of these pseudometastatic lesions is essential in order to avoid unnecessary and potentially hazardous therapeutic intensification.

Oxidant injury to hepatic mitochondrial lipids in rats with dietary copper overload. Modification by vitamin E deficiency

To examine the role of oxidant damage to subcellular membranes in the pathogenesis of copper hepatotoxicity, the effects of dietary copper overload and varying states of vitamin E on biochemical, histological, and ultrastructural features of rat liver were investigated. Weanling male rats were pair-fed for 8 weeks on diets containing normal or high levels of copper in combination with either deficient, sufficient, or excessive vitamin E. Hepatic microsomes and mitochondria, isolated by differential centrifugation, showed similar enrichment and recovery among all experimental groups. Evidence of in vivo peroxidation of membrane lipids (generation of conjugated dienes and thiobarbituric acid reacting substances) was present in mitochondrial but not microsomal preparations from copper-overloaded rats. Serum aspartate aminotransferase, alanine aminotransferase, and cholylglycine (which were increased in all copper-overloaded rats), as well as mitochondrial thiobarbituric acid-reacting substances, were more elevated in vitamin E-deficient rats. In copper-overloaded rats, liver histology showed changes of acute and chronic hepatocyte injury with mild periportal fibrosis; electron microscopy showed abundant copper-containing lysosomes and dilated cristae of hepatocyte mitochondria, findings similar to those in the liver of humans with copper-overload disorders. These findings suggest that an oxidant injury to hepatocyte mitochondria may be one of the initiating factors in hepatocellular damage that leads to hepatic lesions in copper-overload states in humans.

Methotrexate loading of red cell carriers by osmotic stress and electric-pulse methods: ultrastructural observations

Transmission and scanning electron microscopy (EM) of osmotically stressed and electrically pulsed human erythrocyte carriers indicated that the mode of uptake of methotrexate (MTX) varied depending on the method of carrier production. The preswell and electroporation loading methods, apparently by facilitating passive diffusion across the cell membrane, promoted incorporation of the MTX directly into the cytoplasm of the carriers, as evidenced by their variable electron densities. The preswell method produced carriers displaying leptocytic characteristics, whereas the electroporation method produced carriers exhibiting sphero- and stomatocytic transformation. Hypotonic dialysis-prepared carriers took up MTX primarily by endocytosis and secondarily by passive diffusion. Endocytotic activity was not induced by the MTX. Scanning EM revealed that most of the dialysis-prepared carriers exhibited prominent invaginations of the cell surface. Transmission EM of serial thin sections through these carriers revealed numerous fully internalized, membrane-bound vesicles. Endocytotic activity caused progressive loss of membrane and resulted in the sphero- and stomatocytic transformation of the carriers.

Interleukin-2-activated lymphocytes from brain tumor patients. A comparison of two preparations generated in vitro

Two preparations of human recombinant interleukin-2 (rIL-2)-activated lymphocytes from patients harboring malignant brain tumors were characterized as autologous-stimulated lymphocytes (ASL) and lymphokine-activated killer (LAK) cells. ASL were generated from Ficoll-Paque-isolated, nonadherent, defibrinated peripheral blood lymphocytes (PBL) that were stimulated overnight with phytohemagglutinin (PHA) and cultured with rIL-2 (100 U/ml) for 10 days. LAK cells were produced by culturing all PBL in rIL-2 (500 U/ml) for 4 days. In 4-hour chromium release assays, LAK cells showed greater cytotoxicity than ASL against natural killer (NK)-sensitive and NK-resistant tumor cell lines; by 18 hours, the effectiveness of ASL equaled that of LAK cells. By electron microscopic study, PBL, LAK cells, and ASL showed differences. The helper/inducer to suppressor/cytotoxic ratio (T4+/T8+) of PBL, LAK cells, and ASL was 1.1:1, 1.0:1, and 0.4:1, respectively. ASL, when compared with PBL or LAK cells, have a significantly higher percentage of MO1+/DR+ and T8+/9.3+ subpopulations. ASL and LAK cells, used for the therapy of gliomas, are distinct.

Rhabdoid tumor of kidney. A report of 111 cases from the National Wilms' Tumor Study Pathology Center

We review 111 cases of rhabdoid tumor of kidney (RTK), including 79 entered on the National Wilms' Tumor Study (NWTS). Median age at diagnosis was 11 months, with a range from 0 to 106 months. The male:female ratio was 1.5:1. Gross features included a characteristic involvement of perihilar renal parenchyma. A wide histological spectrum was encountered, including nine major morphological patterns (classical, epithelioid, sclerosing, lymphomatoid, histiocytoid, etc.). These appearances invite confusion with other renal neoplasms. Ultrastructural studies were performed in 20 cases; immunocytochemical studies were performed in 11. Vimentin was demonstrated in all tumors; epithelial membrane antigen was seen in 7. Nonspecific decoration of cytoplasmic inclusions by a variety of immunostains was found in several cases. Several findings suggested that RTK might arise from primitive cells involved in formation of the renal medulla. There was no evidence of a histogenetic relationship to Wilms' tumor, although RTK may overlap with mesoblastic nephroma and clear cell sarcoma. Of the 70 NWTS patients with adequate follow-up, 56 (80%) have died. Every patient presenting with distant metastases died, whereas 10 of 20 with negative nodes survived. Survival rates were higher for girls (56.3% versus 11.1%). None of the histological variables had independent prognostic significance.

Anaplastic Wilms' tumor and other clinically aggressive childhood renal neoplasms: ultrastructural and immunocytochemical features

The ultrastructural and immunocytochemical findings in a series of 32 rarely encountered childhood renal malignancies are reviewed. The discussion includes anaplastic Wilms' tumors, renal clear cell sarcomas, rhabdoid tumors, carcinomas, sarcomas, neuroendocrine tumors, and lymphomas. An attempt is made to assess the relative merits of these two techniques in the differential diagnosis of these often troublesome lesions.

Ultrastructure and histogenesis of the renal tumors of childhood: an overview

This review discusses the ultrastructural and immunohistochemical features of the common childhood renal tumors, with an emphasis on their diagnostic usefulness. Speculations regarding their histogenesis also are presented, with the hope that these may serve to diminish some of the confusion surrounding the classification of these morphologically diverse lesions.

Chondroid chordoma

We reject the notion that the concept of "chondroid chordoma" be abandoned in favor of an interpretation of the cartilaginous origin of these lesions. We have demonstrated by electron microscopic and immunohistochemical means that these neoplasms can exhibit distinctly epithelial characteristics in their chondroid as well as their epithelial areas. The presence of desmosomes, cytokeratin, carcinoembryonic, and epithelial membrane antigen in the cells of the chondroid as well as the epithelial areas; the presence of the microtubular inclusions, vimentin, and S-100 protein in the cells of the epithelial as well as chondroid areas; and the intermingling of the two and gradual transitions from one to the other all point to the conclusion that the chondroid and epithelial areas are only differing morphologic expressions of the same entity. The gradual evolution witnessed in the sequential biopsies of this case study, through which a predominantly chondromatous neoplasm became a chordoma of typical histologic appearance, provides further strong evidence to support the contention that chondroid chordoma is a variant of chordoma and not a primary chondrocytic neoplasm.

Malignant fibrous histiocytoma in childhood: a report of two cases and review of the literature

Malignant fibrous histiocytoma (MFH) is a tumor of late adult life not often recognized as occurring in children. Our search of the English literature produced only 27 well-documented examples occurring in the soft tissues, to which we here add 2 additional cases. Both of our cases displayed the classical storiform-pleomorphic histologic pattern typical of such tumors in adults, and both pursued a malignant and rapidly fatal course. Previous reports of this tumor in children are reviewed, and the differential diagnostic considerations briefly discussed. Overall, the clinical features of MFH in children are similar to those reported in adults, and surgical removal remains the key element of successful therapy.

S-100 protein immunohistochemistry and electron microscopy in the diagnosis of Langerhans cell proliferative disorders: a comparative assessment

To better define the roles of S-100 protein immunohistochemistry and electron microscopy in the diagnosis of Langerhans cell proliferative disorders, a comparative assessment of the two techniques was performed using material from 39 cases of histiocytosis X and 2 cases of infantile self-healing reticulohistiocytoma. Both techniques proved highly reliable, but neither alone enabled diagnostic confirmation in all instances. The two techniques proved complementary and used together did enable identification of Langerhans-type histiocytes in all cases studied. Neither was judged clearly superior and both offered certain advantages. Electron microscopy was found overall to be a slightly less sensitive technique, but more specific and less subject to misinterpretation. The S-100 stain was found to be particularly useful in situations where sampling problems were likely to be encountered or where the available specimen was otherwise suboptimal for electron microscopic examination. Because the S-100 stain is the more cost-effective to employ, we now recommend it for the purpose of providing routine diagnostic confirmation. In an investigative setting, however, we continue to recommend electron microscopy as the primary technique.

An unusual banded structure in Ewing's sarcoma

In a largely haemorrhagic and necrotic specimen of Ewing's sarcoma we found banded structures (periodicity of banding about 250 nm) of a type hitherto not known to occur in any normal or pathological tissue. Morphological appearances suggested that these structures had evolved from the fibrin which was always closely associated with them. However, this idea was abandoned because the periodicity of banding of these structures is about ten times greater than the known periodicity of banding of fibrin. These structures have the same periodicity of banding as fibrous long-spacing collagen produced in vitro and about twice the periodicity of banding of fibrous long-spacing collagen found in vivo. However, they lack the fine striations or minor bands of the in vitro fibrous long-spacing collagen. We therefore conclude that the banded structures in this tumour represent a new form of fibrous long-spacing collagen which shares the features of in vitro and in vivo types of fibrous long-spacing collagen.

Small round cell neoplasms: can electron microscopy and immunohistochemical studies accurately classify them?

The answer to the question posed in the title, "Small Round Cell Neoplasms: Can Electron Microscopy and Immunohistochemical Studies Accurately Classify Them?", is obviously "yes"; but a qualified yes--generally yes, perhaps with expertise usually yes, but never just plain yes. Some cases certainly will defy the best attempts even of the most expert in the application of these "special" techniques. And embarrassing as it may be for those of us infatuated with the latest technology to admit, it is with the difficult case especially that old-fashioned technology so often must be depended upon. In his excellent recent appraisal of the role of a variety of special techniques in this application, Triche offers the following comment: "Overall, electron microscopy is probably the most universally useful of all diagnostic techniques other than light microscopy in round cell tumors." The data from our studies certainly point to the same conclusion. With each of the tumors, electron microscopy demonstrated itself to be more reliable than immunohistochemistry. Electron microscopy offers not only greater sensitivity and specificity, but also greater versatility. Immunohistochemistry allows hypothesis testing only. Electron microscopy, on the other hand, can provide answers even when the right questions are not being asked. For example, if a particular small round cell tumor under investigation happens in actuality to represent something other than the neuroblastoma which it is being considered (e.g., a granulocytic sarcoma, liposarcoma, Wilm's tumor, etc.), electron microscopy can reveal this fact, but a neuron-specific enolase stain cannot. Parenthetically, it should also be said that electron microscopy has proven particularly well suited to the examination of fine-needle aspiration specimens. The two spare many patients in our institution the need for a major operative procedure to establish a secure tissue diagnosis. Immunohistochemistry does have a role to play but it is, at least in our opinion, clearly secondary to that of electron microscopy. The concept of replacing electron microscopy with a battery of immunostains has often been advocated as an economic measure, but this argument begins quickly to lose its weight as the number stains included in the battery is increased to cover the diagnostic possibilities. Giving consideration to the capriciousness of some of these stains, there exists with this also an increasing possibility of a spurious or misinterpreted result leading to an errant diagnosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Histiocytosis X

To clarify salient issues pertaining to histiocytosis X--a syndrome that includes Letterer-Siwe disease, Hand-Schuller-Christian disease, and eosinophilic granuloma--the authors review the epidemiologic data and the histologic, morphologic, and clinical bases for diagnosis and prognosis. Histiocytes are defined and their possible histogenesis outlined, and Langerhans cells, which may be a leading element in active lesions, are characterized. The authors outline hypothetic pathogenetic schema, which they recommend be tested by recently developed immunologic and genetic means, since histiocytosis X, at least in its disseminated form, remains an unpredictable disease for which there is no proven effective therapy.

Electron microscopy in histiocytosis X

In an ultrastructural study of 24 cases of histiocytosis X, we were able to demonstrate Langerhans cell granules in all of 18 cases from which tissues had been submitted primarily for electron microscopy and in 4 of 6 cases from which only tissue retrieved from paraffin blocks was available for examination. In a subsequent correlative study we were able to demonstrate Langerhans cell granules in deparaffinized material from 11 of 14 cases (79%) in which they were known to exist. The incidence of histiocytes displaying Langerhans cell granules (in a single plane of section) fell from a median of 48% in samples processed primarily for electron microscopy to 14% in those retrieved from paraffin blocks. Our data suggest that electron microscopy, even when applied to the study of suboptimally preserved material, is a highly sensitive technique for confirming a diagnosis of histiocytosis X.

Rhabdomyosarcoma in children: ultrastructural study of 31 cases

Thirty-one cases of rhabdomyosarcoma in children were studied by electron microscopy. All of the tumors examined fit into a continuum of progressive cellular differentiation mimicking that of normal myogenesis, with increasingly differentiated examples being decreasingly common. We conclude that all childhood forms of rhabdomyosarcoma are essentially embryonal tumors, with many not being sufficiently differentiated at the cellular level to allow positive ultrastructural diagnosis.