Ectopic Pleural Thymoma : Report of a case.

Thymomas are uncommon neoplasms that account for 50% of all masses in the anterior mediastinum. Medial sternotomy is the typical approach for resection. We report a case of an ectopic thymoma within the right pleural cavity in a 76-year old Caucasian women. This patient was diagnosed on preoperative assessment with a large nodal lesion, measuring 12.5 × 9 × 11 cm. Extensive imaging and histology hinted the diagnosis of an ectopic thymoma type B1 according to the World Health Organisation (WHO) classification. Due to the rare location of this tumor, we decided to use a right lateral thoracotomy instead of the more commonly used medial sternotomy. Complete resection of the tumor was performed with relative ease and histopathology verified the diagnosis of a thymoma type B1. No continuity towards the superior anterior mediastinum was documented and the thymoma was considered 'ectopic'. To our knowledge ectopic thymomas are very rare, and few reports have been made about removing thymic tumors by means of a lateral thoracotomy.

The prognostic significance of the DNA content in Ewing's sarcoma: a retrospective cytophotometric and flow cytometric study.

The DNA content of the cell nuclei of Ewing's sarcoma was analysed by means of cytophotometry in situ with image analysis in Feulgen-stained sections in 37 patients, and by retrospective flow cytometry according to the method of Hedley in 26 patients. Different histogram patterns were obtained: normal unimodal or bimodal DNA distributions and abnormal DNA distributions with one or two stem lines, or an abnormal DNA distribution with no stem lines. Both methods enabled us to make a distinction between two groups of Ewing's sarcomas with a different prognosis. All patients with aneuploid tumours died within 5 years after the initial diagnosis. Eleven of 19 (58%) patients with a normal DNA distribution in their tumour, as determined by cytophotometry, are still alive and in good health with a mean survival period of 7.5 years, ranging from 2 to 19 years. Of the group of patients in which flow cytometry revealed a normal DNA pattern, eight of 15 (53%) are still alive and in good health, with a mean survival period of 8 years. These results indicate that both techniques are reliable methods for obtaining prognostic information in Ewing's sarcomas. However, cytophotometry in situ yielded a better discrimination for the overall survival (P < 0.01) than did flow cytometry (P < 0.05). In 19% of the cases there was a discrepancy between the DNA histograms obtained with the two techniques. In five of 26 cases the DNA distributions were classified as normal by one method and aneuploid by the other. Tumour cell representation or selective loss of cells during enzymatic treatment may be responsible for this discrepancy.

The immunophenotype of Ewing's sarcoma. An immunohistochemical analysis.

Since 1963, 53 cases of Ewing's sarcoma have been diagnosed at the N. Goormaghtigh Institute of Pathological Anatomy. All tumours were classified according to their growth pattern as described by Kissane: diffuse, lobular or organoid, the latter with pseudorosettes, or belonging to the fillagree type. In 45 cases, an immunohistochemical examination was carried out on routinely processed material in order to determine the immunophenotype of the tumours and to get more information on the histogenesis of the tumours. Antibodies against cytokeratin, desmin, vimentin, neurofilaments, neuron-specific enolase, Leu7, synaptophysin, chromogranin, the muscle-specific actin, the Von Willebrand factor and the common leucocyte antigen were used in a biotin-streptavidin procedure. The presence of neural markers such as neuron-specific enolase, synaptophysin and Leu7 was proved in the majority of the cases. The expression of the three markers was absent in only two cases. Neurofilaments were demonstrated to be present in 5 of the 6 cases for which fresh material was available. The results of this study point towards a possible neuroectodermal origin of Ewing's sarcoma. This is in agreement with the results of cell culture experiments and of cytogenetic studies.

Nerve sheath tumors: evaluation with CT and MR imaging.

Tumors of nerves are classified into benign (schwannoma and neurofibroma) and malignant nerve sheath tumors. Schwannomas almost always occur as solitary lesions, whereas neurofibromas may occur alone or in a greater number, especially in patients with the peripheral form of von Recklinghausen's disease. Benign nerve sheath tumors often present as asymptomatic, slowly growing soft tissue masses. Although malignant nerve sheath tumors are relatively rare, a sudden increase in the size of a lesion, in particular in a patient with neurofibromatosis, should raise the suspicion of malignant change. On computed tomography (CT) and magnetic resonance imaging (MR) a benign nerve sheath tumor usually appears as a well-defined, oval, spherical or fusiform mass with smooth borders and distinct outlines, located in the subcutaneous tissue or centered at the expected anatomic location of a nerve, with displacement of adjacent soft tissues. Generally nerve sheath tumors have a low density on unenhanced CT scans. On MR they are isointense to muscle on T1-weighted images, whereas on T2-weighted images the signal intensity is high. Both on CT and MR the degree of contrast enhancement is moderate to marked and may be homogeneous or inhomogeneous. MR has become the method of choice for evaluating the anatomic location, contour, and relation of a nerve sheath tumor to adjacent neural, vascular, and muscular structures. The imaging criteria for malignant nerve sheath tumors are not specific enough to distinguish them from other malignant soft tissue tumors, so that neither CT nor MR can establish a definite diagnosis.

Molecular cytogenetic analysis of a complex t(10;22;11) translocation in Ewing's sarcoma.

Fluorescence in situ hybridization (FISH) using chromosome-specific plasmid libraries and chromosome region-specific DNA markers allowed the characterization of a t(10;22;11) (p11.2;q12;q24) in a Ewing's sarcoma (ES). This study illustrates the usefulness of molecular cytogenetic analysis of ES, especially for determining the localization of the translocated 11q24-25 segment in complex or variant translocations.

Vimentin expression of renal cell carcinoma in relation to DNA content and histological grading: a combined light microscopic, immunocytochemical and cytophotometrical analysis.

An immunocytochemical and cytophotometrical analysis of 30 renal cell carcinomas was carried out in order to investigate the expression of cytokeratin and vimentin in relation to the ploidy and mitotic index. Thirty renal cell carcinomas were studied using monoclonal antibodies CAM 5.2 and anti-vimentin in a biotin-streptavidin staining procedure. The renal cell carcinomas were classified according to the criteria of Fuhrman with a nuclear grading from I to IV. All carcinomas expressed cytokeratin, whereas co-expression with vimentin was present only in 53%. Expression for both intermediate filaments was present in aneuploid tumours with a marked nuclear pleomorphism and was more frequently related to a tubulo-papillary and pseudosarcomatous growth pattern. It is suggested that vimentin expression in renal cell carcinomas may be useful as a prognostic index in addition to nuclear grade. DNA content, mitotic rate and tumour stage.

Ileal mucosal mononuclear cells in patients with seronegative spondylarthropathy.

In order to study local immunoregulatory mechanisms in patients with seronegative spondylarthropathy and histological evidence of asymptomatic intestinal inflammation, we determined mononuclear cells in distal ileal mucosa with an indirect immunoperoxidase technique using a panel of monoclonal antibodies. The number of intraepithelial lymphocytes in inflamed mucosa was not significantly increased. They carried mainly the suppressor-cytotoxic CD8 marker (greater than 80%), less frequently the helper T cell marker CD4 and lacked the pan T epitope CD3 in greater than 50%. There were no intraepithelial B cells or natural killer cells. The lamina propria lymphocytes were T and B cells, the former being more numerous. Helper T cells were more frequent than suppressor-cytotoxic T cells. There were no alterations in the proportion of T cells in inflamed mucosa. Natural killer cells were scarce. They occurred in small numbers in a minority of cases with gut inflammation and spondylarthropathy and rarely in inflammatory bowel disease. It is concluded that although there is an increase of lamina propria monocytes, there is no immunoregulatory imbalance in the ileal mucosa of patients with seronegative spondylarthropathy.

Histologic and microbiologic findings in the fallopian tubes of IUD users.

Non-microbial inflammatory changes are more frequent in the oviducts of IUD users than in those of former users and never users. No correlation was found between the incidence of non-microbial tubal inflammation and the interval between IUD use and tubal sterilization, pelvic inflammation and surgery, and parity. Inflammatory response was more common among women using copper devices than among those wearing a non-copper IUD.

A suspected case of late-onset sodium-valproate-induced hepatic failure.

A 15-year-old boy was under anti-epileptic medication (diphenylhydantoine, phenobarbital and Na valproate) for more than five years. He was admitted in cerebral coma and died after 24 hours. The histological findings suggest a valproate induced liver toxicity. This long interval between start of treatment and a possibly related hepatic failure has not been described.