[Pulmonary lymphangioleiomyomatosis. Morphologic and immunohistochemical findings]

Pulmonary lymphangioleiomyomatosis (LAM) is a rare disease affecting only women which is characterised by cystic parenchymal changes and smooth muscle proliferation and has to be considered in the differential diagnosis of interstitial lung disease. The LAM cell is classified as a so-called perivascular epithelioid cell (PEC) showing immunohistochemical co-expression of smooth muscle and melanocytic markers (melanomyopericyte). A total of 18 cases of LAM and 56 cases of various other pulmonary diseases were analysed by immunohistochemistry. For the diagnosis of LAM in transbronchial or open lung biopsies, immunohistochemistry using the antibody HMB 45 is decisive because it shows a highly specific and sensitive, but often only faint reaction for pulmonary LAM. The immunohistochemical detection of nuclear localised microphthalmia transcription factor (MiTF) in LAM as an additional melanocytic marker further emphasises the melanocytic (as well as smooth muscle) line of differentiation within the cells of LAM. Using the concept of a melanomyopericyte, pulmonary LAM could be classified as a hamartomatous interstitial lung disease showing perivascular smooth muscle and partial melanocytic differentiation.

[Congenital pulmonary fibrosarcoma. Differential diagnosis of infantile pulmonary spindle cell tumors]

Primary pulmonary mesenchymal tumors are rare causes of intrathoracic lesions in newborns. We describe a case of pulmonary spindle-cell tumor with features of infantile fibrosarcoma and discuss the differential diagnosis of spindle-cell lesions in this location. In view of further case reports of the literature, this neoplasia can best be categorized in a spectrum of fibroblastic/myofibroblastic differentiated spindle-cell tumors, with excellent prognosis. Especially in congenital lesions a favorable clinical course is to be expected after complete surgical resection. Additional radio- and/or chemotherapy is not recommended.

The association between tumour progression and vascularity in myxofibrosarcoma and myxoid/round cell liposarcoma

Angiogenesis is an important factor in the morphological progression and metastasis of many solid tumours. We studied two homogeneous series of myxofibrosarcoma (MFS) and myxoid/round liposarcoma (MRLS), characterised by distinct vascular patterns and correlated the intratumoral microvessel density (IMD) with morphologic progression in both types of sarcoma. In our study, 43 cases of MFS and 42 cases of MRLS were graded according to established diagnostic criteria. For evaluation of IMD, representative sections were stained immunohistochemically for CD31. After selection of "neovascular hot spots", IMD was calculated by measuring the endothelial surface within twenty 200x fields in relation to the total analysed area. In addition to the correlation of IMD with histological grades of malignancy, a correlation of IMD with the inflammatory infiltrate in MFS was done. To determine whether vascular endothelial growth factor (VEGF) and its receptors, KDR and flt-1, may play a role in the progression of both types of sarcomas, we used mRNA in situ hybridisation (ISH) to study VEGF, KDR and flt-1 expression in selected cases. In addition, the expression of thrombospondin-1, which has been reported to inhibit angiogenesis, and of collagen type I was studied using mRNA ISH. Cases of MFS varied histologically from hypocellular, mainly myxoid, neoplasms (low-grade malignant, 18 cases) to intermediate-grade malignant lesions with increased cellularity and mitotic activity (13 cases), and high-grade malignant cases with marked pleomorphism, high proliferative activity and areas of necrosis in many cases (12 cases). Cases of purely low-grade myxoid liposarcoma (16 cases) were characterised by low-cellularity, mucin pooling and plexiform vasculature. In combined MRLS, these hypocellular areas were admixed with hypercellular, round cell areas (5-80% of the analysed tumour area; 23 cases), and in round cell liposarcoma (three cases) rounded tumour cells predominated (>80% of the analysed tumour area). The average IMD in intermediate and high-grade malignant MFS (4.03 and 4.09, respectively) was significantly higher than in low-grade malignant MFS (2.73). Correlation of vascularity with the inflammatory infiltrate in MFS showed increased IMD only in cases with abundant neutrophils; most of these cases were high-grade malignant neoplasms. In contrast, no statistical correlation between morphological progression and IMD was seen in myxoid liposarcoma (6.08), MRLS (6.57) and round cell liposarcoma (4.07). VEGF mRNA was expressed by tumour cells in all histological grades of MFS and MRLS. VEGF receptor mRNA was weakly expressed by endothelia of newly formed blood vessels in both entities. Interestingly, tumour cells of all analysed cases of MFS strongly expressed collagen type I and thrombospondin-1, while these proteins were not detected in tumour cells of MRLS. In conclusion, morphologic tumour progression in MFS is associated with increased IMD, whereas, in MRLS, no such correlation is seen. Whereas VEGF and VEGF receptor mRNA were expressed in both entities, a characteristic expression profile of collagen type I and thrombospondin-1 in MFS emerged. Further studies are necessary to correlate vascularity and clinical course in MFS and MRLS.

[Intramuscular extremity metastasis of adenocarcinoma of the colon]

Metastases from colorectal carcinoma usually spread along abdominal lymph nodes or are hematogenous to the liver or lungs. So far, 13 cases of metastases to skeletal muscle have been described. In the following report, the case of a 72-year-old woman with a colonic carcinoma and metastases of this tumor in the thigh is described. Other reports about muscular metastases of colorectal tumors are discussed.

APC and beta-catenin in alveolar soft part sarcoma (ASPS)--immunohistochemical and molecular genetic analysis

Apart from its role in cell-adhesion, beta-catenin is regarded as an oncoprotein, the cytoplasmic level of which is regulated by APC as a tumor suppressor protein. Changes of chromosome 5q, the region that includes the APC-gene, are known to be important in the pathogenesis of fibromatosis; however, little is known about the significance of APC and beta-catenin in other mesenchymal tumors. Therefore, we used immunohistochemistry and DNA-analysis to investigate four cases of alveolar soft-part sarcoma (ASPS) as a mesenchymal tumor with a distinct histologic appearance. In three cases of ASPS the APC-gene product was found to have strong nuclear expression and only faint cytoplasmic staining. Beta-catenin showed a partly membranous, partly strong intracytoplasmic expression. No gene mutations for APC and beta-catenin were detected in any of the four cases. These investigations suggest that, apart from their function in carcinogenesis and fibromatoses, APC and beta-catenin play a role in the pathogenesis of soft tissue tumors such as ASPS. The significance of a striking nuclear accumulation of non-mutated, virtually functionally active APC-tumor suppressor protein has not yet been investigated. A nuclear function of APC in ASPS in down-regulating nuclear transcription processes linked to overexpression of beta-catenin, as is known in colorectal carcinogenesis, may be hypothesized.

Beta-catenin in soft tissue sarcomas: expression is related to proliferative activity in high-grade sarcomas

Besides its role in cell adhesion, beta-catenin exerts a function as an oncoprotein. The aim of this study was the characterization of its expression, possible mutation, and the assessment of beta-catenin as a prognostic indicator for soft tissue sarcomas. A total of 115 soft tissue sarcomas were analyzed using immunohistochemistry, immunogold-electron microscopy, and DNA analysis. Information from 56 patients was available for follow-up. A statistically significant correlation was found between intracellular distribution of beta-catenin and the proliferative activity (MIB-1 expression) in high-grade sarcomas (P = .0008). Beta-catenin was identified with intracytoplasmic and nuclear accumulation, showing additional membranous staining in sarcomas with epithelioid pattern. Ultrastructurally, a colocalization between beta-catenin and nuclear heterochromatin was demonstrated. In 22 analyzed tumors, only one (yet undescribed) mutation of the beta-catenin gene (C-A transversion) could be detected. Prognostic validity of the cellular expression of beta-catenin, however, was not proven. Apart from its membranous function as an effective molecule for cell-adhesion in sarcomas with epithelioid pattern, beta-catenin may act as an oncoprotein in sarcomas with intracytoplasmic and nuclear localization with binding to nuclear DNA. A previously discussed stimulation of cell proliferation caused by an increased beta-catenin level can also be postulated for high-grade soft tissue sarcomas in correlation with the rate of proliferation. Mutations of the beta-catenin gene are probably of lesser importance for the accumulation of beta-catenin in soft tissue sarcomas.

Patterns of expression and secretion of vascular endothelial growth factor in malignant soft-tissue tumours

Vascular endothelial growth factor (VEGF) is an important cytokine especially in the process of tumour angiogenesis. A total of 46 soft-tissue sarcomas were analysed for the expression and possible secretion of VEGF by immunohistochemistry, in-situ hybridisation, and enzyme-linked immunosorbent assays (ELISA). VEGF was demonstrated immunohistochemically in tumour tissue in 45 of 46 cases. The detection of mRNA transcripts yielded evidence of synthesis of VEGF in these sarcomas. ELISA could be performed in 21 cases. Higher concentrations of VEGF were found in tumour-related intraoperatively sampled venous blood in 16 out of 21 patients (76%) than in systemic concentrations taken preoperatively. The results indicated the secretion of VEGF by tumour cells although these raised concentrations were not statistically significant. In 12 out of these 16 patients (75%) a concurrent moderate to strong immunoexpression of VEGF was detected. The relevance of VEGF blood concentrations as a potential "progress parameter" for the course of disease remains questionable. This is mainly due to the lack of statistical significance in the difference between systemic VEGF concentrations in patients and those of a control group. Further long-term follow-up studies are needed, which should include patients with tumour recurrences.

The APC protein binds to A/T rich DNA sequences

The tumor suppressor protein APC (Adenomatous Polyposis Coli) is localized in the cytosol and in the nucleus. In this study, we demonstrate that the nuclear APC protein level is high in cells in the basal crypt region of the normal colorectal epithelium. Strikingly, the APC protein staining resembles the staining pattern of a nuclear proliferation marker. As a first step towards a possible role of the nuclear APC protein, we provide data showing the direct interaction of the nuclear APC protein with DNA. A nuclear APC isoform precipitates with matrix-immobilized DNA. Vice versa, the immunoprecipitation of APC from nuclear lysates results in co-precipitation of genomic DNA. Using recombinant APC fragments we mapped three DNA binding domains: one within the beta-catenin binding and regulatory domain, and two in the carboxyterminal third of the APC protein. All these three domains contain clusters of repetitive S(T)PXX sequence motifs that were described to mediate the DNA interaction of many other DNA binding proteins. In analogy to S(T)PXX proteins, the APC protein binds preferentially to A/T rich DNA sequences rather than to a single DNA sequence motif.

Intracellular distribution of beta-catenin in colorectal adenomas, carcinomas and Peutz-Jeghers polyps

The interaction of the adenomatous polyposis coli (APC) tumor-suppressor protein and the intracellular cell-adhesion protein beta-catenin is crucial for the development of colorectal tumors. Since functional nuclear complexes of beta-catenin with transcription factors have been identified recently, the knowledge of level and distribution of beta-catenin in sporadic colorectal tumors will give important insights into the intracellular mechanism of sporadic colorectal tumor initiation and progression. In contrast to the familiar adenomatous polyposis syndrome and to the majority of sporadic colorectal tumors, Peutz-Jeghers (PJ) syndrome is not caused by mutations in the APC gene. Since PJ syndrome is an inherited disease with an increased risk for gastrointestinal adenocarcinoma, whether beta-catenin plays a similarly important role for the development of PJ polyps should be further investigated. For these reasons we analyzed the distribution of beta-catenin in a total of 60 sporadic colorectal tumors at different stages of progression and in 6 PJ polyps. In addition to the localization at the cell-to-cell border membranes, fluorescence immunohistochemistry revealed a nuclear accumulation of beta-catenin in single tumor cells of 10/14 small adenomas with mild dysplasia and in 14/16 adenomas with moderate dysplasia. Further tumor progression is accompanied by an expansion of cells with increased level of nuclear and cytoplasmic beta-catenin. These cells were observed in 5/16 adenomas with moderate dysplasia and in 15/15 adenomas with severe dysplasia. In all adenocarcinomas investigated, as well as in the corresponding lymph node metastases, a sub-population of tumor cells exhibited a remarkably increased level of beta-catenin within the entire cytoplasm and the nucleus. In contrast to the situation in sporadic colorectal tumors, nuclear and cytoplasmic beta-catenin was not increased in PJ polyps. These results point to an extensive redistribution of beta-catenin, which starts early in colorectal tumorigenesis. The nuclear accumulation in single cells of small adenomas can be considered as the first visible sign of the loss of APC function. Thus the immunohistochemical detection of beta-catenin distribution could serve as a criterion for estimating the malignant potential in the clinico-pathological evaluation of colon tumors during their early progression.

[Intracellular distribution of beta-catenin in soft tissue tumors]

AIMS

beta-Catenin originally known as an intracellular mediator of epithelial cell-to-cell adhesion is also involved in signal transduction processes. Since its important function in colorectal carcinogenesis has recently been recognized, the aim of our study was to investigate whether a similar intracellular distribution of beta-catenin can be detected in sarcomas and sarcoma-like lesions.

METHODS

45 soft tissue tumors were examined by immunohistochemistry.

RESULTS

Different types of beta-catenin-distribution were observed: A more continuous localization at the cell membrane was evident especially in epithelioid-like sarcomas. In contrast only focal staining of cell membranes could be found in different tumors as well. Further on increased cytoplasmatic beta-catenin levels were detected in various types of tumors.

CONCLUSIONS

The localization of beta-catenin at the cell membrane serves as a hint for a function of beta-catenin in cell adhesion of mesenchymal tumors apart from epithelial tissues. A nuclear and intracellular accumulation of beta-catenin has been observed in progression of colorectal tumors. The findings of increased levels of beta-catenin in soft tissue tumors may indicate a similar important function in the pathogenesis of these neoplasias.

[Primary synovial sarcoma of the lung]

In the biopsy material of a polypoid intrabronchial lesion of a 54-year-old male patient with radiologically established lung tumor, spindle-cell neoplasia was seen. No clear histogenetic classification of the submucous tumor process was possible. After resection of the right upper lobe of the lung, including the results of additional immunohistochemical analyses, the tumor was classified as biphasic synovial sarcoma. This was suggested mostly by immunohistochemical detection of the epithelial membrane antigene (EMA) and of vimentin. Extensive clinical examinations ruled out the possibility of a primary tumor with extrapulmonary localization. This case report shows the problems faced in correctly classifying the histogenesis or the direction of differentiation in extremely rare cases of primary pulmonary synovial sarcoma. Especially in small biopsy samples showing a submucous spindle-cell tumor of the lung, apart from frequent sarcoma metastases, the presence of primary synovial sarcoma of the lung has to be considered in the differential diagnosis.

MDM2 amplification and loss of heterozygosity at Rb and p53 genes: no simultaneous alterations in the oncogenesis of liposarcomas

PURPOSE

The present study aimed to investigate the status of alterations of the MDM2, Rb and p53 genes in a series of 45 liposarcomas. Furthermore, the possible correlation with histological and clinical parameters was studied.

METHODS

MDM2 amplification was examined by non-radioactive Southern blot hybridization with a human MDM2 cDNA probe. Mutations in the p53 gene were screened by polymerase chain reaction/single-strand conformation polymorphism analysis and direct sequencing. To study loss of heterozygosity (LOH) at the tumor-suppressor genes Rb and p53, we used four polymorphic intragenic Rb markers (introns 1, 17, 20, and 25) and two p53 markers (intron 1 and exon 4).

RESULTS

MDM2 amplification was found in 19 of 45 liposarcomas (42.2%). The frequency of LOH in Rb and p53 was nearly identical (22%). In 4 of 9 tumors (44.4%) with LOH, allelic loss was a concurrent event in both genes. Of 45 liposarcomas, 6 (13.3%) showed p53 mutations. Overall, alterations of the p53/MDM2/Rb pathway occurred in 30 of 45 liposarcomas (66.6%). In contrast to myxoid and pleomorphic variants, well-differentiated liposarcomas were characterized by a high frequency of MDM2 amplification, a lack of LOH of Rb and p53, and p53 mutations.

CONCLUSIONS

Obviously MDM2 amplification and LOH at the Rh and p53 genes do not occur simultaneously in the oncogenesis of liposarcomas, as is the case for MDM2 amplification and p53 gene mutations (with one exception). We suggest that well-differentiated, myxoid and pleomorphic liposarcomas are characterized by a different pattern of molecular alterations.

Hepatocyte growth factor/scatter factor and its receptor c-Met are overexpressed and associated with an increased microvessel density in malignant pleural mesothelioma

Hepatocyte growth factor/scatter factor (HGF/SF) stimulates cell proliferation, motility and invasiveness via its receptor c-Met during embryogenesis and repair processes. It induces angiogenesis, promoting endothelial cell migration and capillary-tube formation in vivo. Co-expression of HGF/SF and c-Met receptor results in enhanced tumour growth, invasiveness and a mesenchymal-epithelial transition in some experimental tumours. Since mesothelioma cells have been reported to express c-Met receptor and to migrate in response to HGF/SF, we investigated human malignant pleural mesotheliomas for the demonstration of possible co-expression of the growth factor and its receptor. The microvessel density of the tumours was also analysed in order to assess the influence of HGF/SF expression on tumour angiogenesis. Thirty-nine paraffin-embedded specimens of malignant pleural mesotheliomas were immunostained by anti-HGF/SF and anti-c-Met antibodies and semiquantitatively evaluated. c-Met mRNA expression was visualised in ten tumour samples by a fluorescent in situ hybridisation method. Microvessel density was calculated by counting microvessels with a high-power field (200x) on von-Willebrand-factor-stained slides. We found an increased production of HGF/SF in 33/39 tumours and a corresponding overexpression of c-Met receptor in 29/39 specimens. The FISH method detected increased transcription of c-Met mRNA in malignant cells and in neighbouring vascular endothelial cells. HGF/SF-positive mesotheliomas had significantly higher microvessel densities compared to their HGF/SF-negative counterparts. The observed co-expression of HGF/SF and c-Met in malignant pleural mesotheliomas suggests a possible self-stimulation (autocrine loop) of tumour cells. On the basis of the significantly higher microvessel density values of malignant mesotheliomas overexpressing HGF/SF, we postulate, that HGF/SF may be an additional relevant factor in tumour angiogenesis in malignant pleural mesotheliomas.

Expression of type IV collagenase correlates with the expression of vascular endothelial growth factor in primary non-small cell lung cancer

Tumor growth and metastasis are angiogenesis-dependent processes initiated and regulated by a number of cytokines. Vascular endothelial growth factor (VEGF) is a potent angiogenic protein with a selective mitogenic effect on vascular endothelial cells, known to be involved in physiological (embryogenesis) and pathophysiological (rheumatoid arthritis, tumor) angiogenesis. An increased expression of matrix metalloproteinase type IV collagenase has been reported in invading endothelial cells in vitro and in malignant cells, degrading structures of the basement membranes in various human malignancies. In the present study we investigated the expression of the genes for type IV collagenase and vascular endothelial growth factor (VEGF) in 40 cases of primary non-small-cell lung cancer (NSCLC). Specimens were immunostained by an antibody directed against VEGF and mRNA transcripts of VEGF and type IV collagenase were localized by non-radioactive in situ hybridization. VEGF mRNA was detected in 33 neoplasms, while in 23 cases transcripts of the type IV collagenase gene were visualized by digoxigenin-labeled cDNA probes. Transcripts of both mRNAs were detected in malignant cells. Furthermore, anti-VEGF immunostaining was present in newly formed microvessels close to the atypical cells, and mRNA of type IV collagenase was present in stromal cells adjacent to the tumor. A statistically significant correlation was found between the expression of type IV collagenase and VEGF (P = 0.0061). These data suggest a double role for type IV collagenase in the metastatic process of NSCLC: (1) facilitating the invasion of tumor cells by the proteolytic cleavage of the basement membrane and (2) similarly supporting the endothelial cell invasion essential for tumor angiogenesis. Furthermore, our findings sustain the hypothesis that metastatic spread and angiogenesis are associated with a clonal expansion of highly angiogenic and invasive tumor cell clones.

Expression of c-Met receptor and hepatocyte growth factor/scatter factor in synovial sarcoma and epithelioid sarcoma

Overexpression of c-Met receptor/hepatocyte growth factor (scatter factor) system (c-Met/HGF/SF) as a physiologically paracrine cellular signaling system is thought to be involved in the progression of malignant tumours. In 26 synovial sarcomas and epithelioid sarcomas, c-Met and HGF/SF expression was analysed immunohistochemically. There were 10 biphasic synovial sarcomas, 7 of which showed moderate to strong c-Met expression in epithelial areas compared with the fibrous component, with corresponding expression of HGF/SF. Six of 9 monophasic fibrous synovial sarcomas showed only very faint c-Met and corresponding HGF/SF expression. In 7 epithelioid sarcomas strong expression of c-Met and HGF/SF was observed within epithelioid tumour cells. Non-radioactive in situ hybridization demonstrated the synthesis of c-Met receptor in tumor cells by detecting c-met-mRNA. This analysis shows that in synovial sarcomas and epithelioid sarcomas, tumour entities with epithelial and mesenchymal structures, c-Met and HGF/SF overexpression can be detected, indicating a role of this signaling system in these subtypes of sarcoma, and especially in the more epithelioid tumour phenotype. An autocrine interaction between overexpressed c-Met receptor and HGF/SF may be hypothesized.

Expression and localization of vascular endothelial growth factor and its receptor flt in pulmonary sarcoidosis

Vascular endothelial growth factor (VEGF) is a multifunctional cytokine, which has recently been reported to enhance the activation and migration of monocytes through the flt receptor in vitro, which are key events in granuloma formation of granulomatous disorders and in sarcoidosis. Since activated macrophages and monocytes are known to be involved in sarcoid granuloma formation in sarcoidosis, we investigated the expression of VEGF and its receptor flt in 33 paraffin-embedded lung tissue biopsies of patients with pulmonary sarcoidosis. VEGF-mRNA was localized by nonradioactive in situ hybridization, VEGF and flt expression were visualized immunohistochemically. We found an increased transcription and protein production of VEGF and an overexpression of flt in activated alveolar macrophages, in epitheloid cells, and in multinuclear giant cells of pulmonary sarcoid granulomas.

[Heart rupture after mitral valve replacement. Pathologic-anatomic findings]

The rupture of the free left ventricular wall is considered a serious complication following mitral valve replacement. We report about 3 cases characterized by similar pathologic-anatomical findings within the region of the left ventricle after mitral valve replacement. Following resection of the original and pathologically altered mitral valve and implantation of a prosthesis, rupture of the left ventricular wall occurred in short time intervals ranging from 1 to 12 h postoperatively. All cases represented a transverse midventricular disruption located between the mitral valve anulus and the resected papillary muscles. The histologic findings included necrotic, damaged myocardial structures with considerable bleeding to the interstitium. Inflammatory infiltration could be detected within the myocardial defects. Abnormal pathologic findings of the coronary arteries or intraoperative lesions could be excluded by thorough autoptic studies. Because of central localization of the ventricular disruption between the mitral valve anulus and the papillary muscles a direct traumatic myocardial injury caused by mitral valve orotheses is to be excluded. When taking into account several reports from literature in combination with our described findings, in autopsy, a loss of contractile integrity of the left ventricle following resection of mitral valve apparatus, especially the chordae tendinaea, should be considered as primary cause for this type of ventricular rupture. This destabilization will lead to a regionally stressec myocardial "stretching" which finally results in rupture of the left ventricular free wall. The described pathogenetic concept seemingly represents the decisive mechanism of this transverse midventricular disruption in all 3 cases. To prevent such post-operative complications, only very limited resection of the mitral valve apparatus should be performed to maintain parts of the chordae tendineae.

[Pulmonary lymphangioleiomyomatosis in tuberous sclerosis]

Pulmonary lymphangioleiomyomatosis was diagnosed in a 26-year-old woman with recurrent pneumothorax by histological evaluation of a lung biopsy obtained during video-thoracoscopy. A tumour of the right kidney had been removed 2 years previously; the histological picture was that of an angiomyolipoma. Immunohistochemical staining for anti-smooth muscle actin gave a strongly positive reaction in the tissue of the renal angiomyolipoma and in the pathologic lung tissue. Additional investigations showed an asymptomatic intracerebral tumour 5 cm in diameter in the left frontal lobe (brain scan). This multilocal renal, pulmonary and cerebral manifestation of benign mesenchymal proliferating tumours supports the classification of this case in the tuberous sclerosis complex.

[Malignant lymphoma and colon carcinoma 3 years after heart transplantation and immunosuppression]

Three years after heart transplantation and immunosuppressive therapy, a 66-year-old man suffered from dyspnea and showed symptoms mainly due to right heart failure. Malignant tumor cells were discovered within extensive pleural effusion. Computed tomography revealed two lesions of the liver suspicious of metastases, and recurrent blood in the stools was evident. The patient deteriorated rapidly and died 3 weeks after admission. Autopsy findings included an adenocarcinoma of the cecum (grade II) with metastases to the liver. High-grade immunoblastic non-Hodgkin's lymphoma of plasmoblastic differentiation was diagnosed, located within the mediastinal soft tissues and infiltrating the peri- and myocardium. Mesenteric lymph nodes were enlarged with histological verification of malignant lymphoma. The lymphatic tumor masses had caused considerable compression of the heart and vessels, leading to the signs of cardiac failure. The development of metastasizing colonic carcinoma and high-grade immunoblastic non-Hodgkin's lymphoma 3 years after heart transplantation and immunosuppressive therapy must be considered an unusual combination. Malignent lymphomas following heart transplantation have been described several times.

Clinical monitoring during carbamazepine slow-release, once-daily monotherapy

Forty-eight patients with complex partial and/or tonic-clonic seizures were treated with an 8 p.m. single dose of carbamazepine slow release (CBZ-SR) monotherapy. The steady-state serum level profiles of carbamazepine (CBZ) and its metabolites CBZ-10,11-epoxide (CBZE) and 10,11-dihydro-CBZ-10,11-diole (CBZD) during 24 h in 21 of 48 patients treated with daily single doses of 8.4 (+/- 2.4) mg/kg body weight CBZ-SR were determined by a high-performance liquid chromatography procedure. The 8 a.m. CBZ levels correlated very well with the mean CBZ levels of the 24-h profile. Unlike CBZD, the individual 24-h mean CBZE levels also correlated well with the respective CBZ levels (CBZE = 14.2% +/- 2.9 of CBZ). Increasing CBZ-SR doses does not result in a proportional increase of CBZ levels. Clinical efficacy of changing from CBZ standard tablets under mono- or combination therapy or from therapy with other antiepileptic drugs to once-daily evening CBZ-SR monotherapy or commencement CBZ-SR therapy in previously untreated patients was monitored in 35 of 48 patients for a period of 8 months to 2 years. Complete seizure control was observed in 51% of patients and more than 75% reduction of seizure frequency in 14%. Eight of 11 previously untreated patients became seizure free. With change from CBZ monotherapy to CBZ-SR single-dose therapy, five of six patients became seizure free. Changing from other therapeutic regimens to CBZ-SR once-daily evening monotherapy was less successful.

Initial experience with 99m Tc-hexamethyl-propylene amine oxime (HM-PAO) single photon emission computed tomography (SPECT) in patients with focal epilepsy

Brain single photon emission computed tomography (SPECT) was performed in 16 patients with focal epilepsy, as well as EEG, using 99m Tc-HM-PAO SPECT and a rotating gamma camera system. Pathological Tc-HM-PAO SPECT findings were registered in 75%. CT was positive in 25%. MRI was positive in 76%. The results of Tc-HM-PAO SPECT findings were compared with those of CT and MRI. 61% of the MRI findings correlated with the pathological SPECT findings with respect to the side of the hemisphere, and in 75% of the patients the focal EEG abnormality and the pathological Tc-HM-PAO-SPECT findings were localized in the same hemisphere.

Effect of valproic acid treatment on spike-wave discharge patterns during sleep and wakefulness

7 patients suffering from absences were recorded before antiepileptic treatment, in the early phase of valproate monotherapy and after having reached steady state. Recordings made with the Oxford-Medilog 4-channel cassette recorder were analyzed visually as well as by a computerized s-w pattern recognition approach, the latter facilitating quantification of pattern characteristics (number, amplitudes and duration of spikes and waves). Measurements were made separately for epochs of wakefulness and sleep. Compared to the premedication phase the amount of s-w discharges in 24 h showed an average reduction of more than 90%. For the majority of the patients, 24-hour discharge profiles showed a maximum in the early morning. Duration and amplitude of both spike and wave elements was higher during sleep. For the waking state, the ratio wave amplitude/spike amplitude was found to be increased under medication.