[Morphology and histogenesis of so-called fibrous mesothelioma (submesothelial fibroma)]. / O morfologii i gistogeneze tak nazyvaemoi fibroznoi mezoteliomy (submezotelial'noi fibromy).

Clinico-morphological characteristics of a tumor (6 observations) designated in the literature as fibrous mesothelioma are presented. This benign slowly growing tumor appears as an incapsulated dense nodule connected with the visceral layer of the pleura by a thin fibrous "pedicle". Microscopical structure of the tumor consists of outgrowths of monomorphic spindle-shaped cells, hyalinosis foci and abundance of blood vessels in some of its areas. Tumor cells ultrastructurally correspond to fibroblast indicating the connective tissue genesis of the so-called fibrous mesothelioma. This tumor should be distinguished from the group of mesotheliomas and be better called submesothelial fibroma.

[Electron-microscopic study of myogenic neoplasms]. / Elektronno-mikroskopicheskoe issledovanie miogennykh novoobrazovanii.

Electron microscopic study of leiomyoma of skin arteries, oesophagus leiomyoma, leiomyosarcoma and rhabdomyosarcoma was carried out. In the tumor cells myofilaments were found sometimes forming hexagonally packed myofibrilles, formations resembling desmosomes. This permitted the establishment of valid myogenic histogenesis of these neoplasias.

[Unusual (epithelioid) leiomyoblastoma of the stomach]. / Prichudlivaia (épitelioidnaia) leiomioblastoma zheludka.

The authors present clinical and morphological characteristics of gastric leiomyoblastoma (25 cases) nominated by Soviet investigators as a myoid or angioleiomyomatous variant of a glomus tumor. The tumor was composed of leiomyomatous sites, clusters of epithelioid cells with apparently empty cytoplasm and frequently odd nuclei. Morphological criteria are suggested referring leiomyoblastoma to mature, infiltrative and malignant. Electron-microscopic examination in 8 cases provided evidence for myogenic origin of the neoplasm. Smooth muscle differentiation is shown to resolve with growing of cell proliferation and relevant atypia.

[Alveolar soft tissue sarcoma]. / Al'veoliarnaia miagkotkannaia sarkoma.

Clinical and morphological manifestations of alveolar soft tissue sarcoma (ASTS) are presented on the basis of 19 examinations performed by the authors and data available in the literature. ASTS has been found to be more common in young women and to be usually located in the thick layers of the proximal parts of the extremities. The tumor generally shows slow growth and late occurrence of metastases. It has been demonstrated that ASTS has an organoid structure, namely alveolar grouping of cells, abundance of capillaries, and its cells contain PAS-positive inclusions. In atypical ASTS, the prognosis has been found to be less favourable. The crystalloid inclusions that are absent in other soft tissue neoplasms are a characteristic ultrastructural sign of ASTS. The genesis of ASTS remains controversial but it cannot be ruled out that it is related to the elements of the APUD-system.

[Electron-microscopic changes of the brain in acute experimental peritonitis (AEP)]. / élektonno-mikroskopicheskie izmeneniia golovnogo mozga pri ostrom experimental'nom peritonite.

It is shown that changes in the vessels of the central nervous system, neurons and interneuron links--synapses develop in AEP. Increasing diffuse-focal destructive brain changes are morphological substrate of toxico-hypoxic encephalopathy and basis for disturbances of an integrative-trigger action of the brain.

[Ultrastructure of malignant fibrosarcoma]. / Ul'trastruktura zlokachestvennoi fibrosarkomy.

Electron microscopic examinations of two malignant fibroxanthomas revealed some ultrastructural features characteristic of this tumor. The tumor elements were represented by histiocyte-like, fibroblast-like and little differentiated cells. In some of the latter the signs of macrophage differentiation could be seen and therefore a possibility of their transformation into histiocytes is assumed.

[Ultrastructural features of fibrosarcoma]. / Ul'trastrukturnye osobennosti fibrosarkomy

An electron-microscopy investigation of two fibrosarcomas was carried out. Blastomatous elements were represented by fibroblasto-like cells. In their cytoplasm there were observed phaged fragment of collagenic fibrils, and in small canals of the granular endoplasmic reticulum--crystalloid formations. Diagnostic significance of these findings is discussed.

[Morphology and histogenesis of soft tissue chordoid sarcoma]. / O morfologii i gistogeneze khordoid-sarkomy migakikh tkanei.

The data of examinations of 6 chordoid-sarcomas of soft tissues which, owing to myxomatosis of the interstitial substance and vesicle-like cells containing glycogen, are similar in structure with skeletal chordoma are presented. It is emphasized that choroidsarcoma, unlike chordoma, has the ultrastructural features of cartilage differentiation: collagenization of the matrix, similarity of some tumour cells to chondrocytes. These data suggest that chordoid-sarcoma is histogenetically associated with rudiments of mesenchyma responsible for cartilage formation.

[Peripheral nerve ectomesenchymoma (neuroectomesenchymoma): a malignant tumor made up of neural crest elements]. / Ektomezenkhimoma (neiroéktomezenkhimoma) perifericheskogo nerva: zlokachestvennaia opukhol' iz élementov nevral'hogo grebeshka.

Characteristics of a little-studied tumor of soft tissues are described on the basis of the author's own material (4 observations) and data from the literature. The matter at issue is a benign or malignant schwannoma (less frequently, ganglioneuroblastoma) in which there are areas of rhabdomyosarcoma and sometimes tumor elements of mesenchymal origin (angio- lipo-, or osteogenic sarcoma). As a rule, this tumor is located along the peripheral nerve or arises in one of the nodes in Recklinghausen's disease and has a trend to hematogenic metastasising. It is suggested that the source of growth of neoplasias of this kind are the cells of "neural crest" migrating in the process of embryogenesis. These cells are responsible for the formation of lemmocytes, ganglial elements and melanocytes, as well as ectomesenchyma from which, in its turn, a part of cross-striated musculature is formed. Therefore, the tumors described in the paper should be designated as "neuroectomesenchymoma" (according to some authors, ectomesenchymoma).

[Histological and ultrastructural characteristics of Abricosov metastasizing tumor]. / Gistologicheskie i Ulstrastrukturnye osobennosti metastaziruiushchei opukholi Abrikosova.

An observation of granular cell Abrikosov tumor metastasizing into lymph nodes is presented. The diagnosis was confirmed by electron microscopy. The ultrastructural features of the tumor confirming its neurogenic origin are described. This is indicated, in particular, by the similarity of the tumor cells with lemmocytes, detection of a basal membrane in some of them, as well as the presence of axonlike projections. The content of some cytoplasmic inclusions was found to be an accumulation of microtubules.

[Pathological anatomy of thymus gland tumors]. / Patologicheskaia anatomiia opukholei vilochkovoi zhelezy.

The paper presents detailed morphological characteristics of 31 thymomas and 25 microscopically similar neoplasias of the anterior mediastinum (carcinoid, seminoma, lymphogranulomatosis, angiofollicular lymphoma, etc). The term "thymoma" is determined as a tumour consisting of two components: mandatory epithelial one and lymphocytes. The diversity of the morphological picture of thymomas is determined mainly by the variability of the epithelial component. The special features of the ultrastructural organization of thymomas (the presence of desmosomes, tonofibrils and basal membrane) were revealed which facilitate the differential diagnosis of the anterior mediastinum tumours.

[Malignant fibrous histiocytoma of the larynx]. / Zlokachestvennaia fibroznaia gistiotsitoma gortani.

A rare case of larynx malignant fibrous histiocytoma is presented. Histologically and ultrastructurally, the tumour was similar to malignant fibrous histiocytoma of other organs. The patient was followed up for 2 years after surgical treatment and preoperative irradiation. No recurrence and metastases were observed.

[The fibroepithelial variant of basal-cell skin cancer (Pincus' "premalignant" fibroepithelioma)]. / Fibroépitelial'nyi variant bazal'nokletochnogo raka kozhi ("predzlokachestvennaia" fibroépitelioma Pinkusa).

12 cases of the basal cell carcinoma fibroepithelial variant are studied morphologically. This variant of basal cell carcinoma is erroneously diagnosed as adenoid variant of seborrheic keratosis, tubular syringoadenoma or the reverse. Main differential-diagnostic criteria allowing to distinguish a fibroepithelial variant of basal cell carcinoma from an adenoid variant of seborrheic keratosis are multicentric foci of superficial basalioma as well as the absence of hyperkeratosis and intraepithelial carcinomatous cysts. The tumour differs from tubular syringoadenoma by the lack of tubular structures with two-layer epithelial lining and cysts with signs of secretory activity.

[Clinico-morphologic and electron microscopic characteristics of chemodectoma of the neck]. / Kliniko-morfologicheskaia i élektronno-mikroskopicheskaia kharakteristika khemodektomy shei.

Chemodectoma of the neck is one of the rare tumors occurring in man. The paper presents an observation of cervical chemodectoma found in a patient aged 31 years. For preoperative differential diagnosis, carotid angiography, ultrasound and radioisotopic examinations were used, which allowed the tumor located at the bifurcation of the left carotid artery to be diagnosed. The material taken during the surgery was histologically and electron microscopically examined to verify benign chemodectoma (an alveolar variant).

[Differential diagnosis of epithelial thymoma and seminoma (histological and electron-microscopic study)]. / K voprosy o differentsial'noi diagnostike epitelial'noi timomy i seminomy.

The paper describes two observations of thymus gland tumours: epithelial thymoma and seminoma. Differential diagnosis of these tumours is very important for the proper selection of the method of treatment as seminoma is more radio-sensitive than epithelial thymoma. Epithelial thymoma is characterized by coarse-fiber stroma, perivascular grouping of cell elements and the lack of glycogen in them. Seminoma consists of light and dark cells containing much glycogen in their cytoplasm. Differences between these tumours are most clearly seen in electron microscopic studies. In epithelial thymoma cells have processes, numerous tonofilaments, desmosomes, and basal membrane. Seminoma cells contain glycogen, no tonofilaments or basal membrane, few desmosomes.

[Lymphogranulomatosis of the thymus gland ("granulomatous thymoma")]. / Limfogranulemotoz vilochkovoi zhelezy ("granulematoznaia timoma").

Thirteen tumors of questionable genesis located in the thymus were studied. The microscopical structure of these tumors was identical to lymphogranulomatosis of other localization. Reactive proliferation of the thymic epithelium and cyst formation are characteristic of lymphogranulomatosis primarily developing in the thymus. The disease was not "granulomatous thymoma" since giant multinuclear cells by their structural characteristics corresponded to reticular elemens and the epithelial component was absent in extrathoracal formations.

[Spindle-cell thymoma (a histological and electron microscopic study)]. / Veretenokletochnaia timoma (gistologicheskoe i elektronno-mikroskopicheskoe issledovanie).

The paper describes 12 cases of spindle cell thymoma without myasthenia or any other syndromes such as hypogammaglobulinemia, hypoplasia of the red sprout of the bone marrow. In most patients the tumours were detected roentgenologically. Microscopic diagnosis of spindle cell thymoma is based on the detection in it of epithelial cell structures. In those cases where the tumours were represented by spindle cells alone, verification of the tumor was possible only by electron microscopic studies (the presence in the cells of tonofilaments, desmosomes and basal membrane).

[Benign tumors of the peripheral nerve sheaths]. / Dobrokachestvennye opukholi iz obolochek perifericheskikh nervov.

Benign tumors from sheaths of peripheral nerves (25 neurolemmomas and 6 neurofibromas) were studied. The ultrastructural data presented attest to the principal differences between these tumors and the possibility of their differential diagnosis. The typical signs of tumor cells of neurilemmoma include numerous complicatedly interwoven processes not infrequently forming " pseudomesaxonal " structures, and the presence of permanent basal membrane. These signs indicate the histogenetic relationship of neurilemmoma with cells of the Schann sheath of the peripheral nerve ( lemmocytes ). Neurofibroma tumor cells were characterized by the presence of bipolar thin, long non-interwoven cytoplasmic processes with inconstant basal membrane, desmosome-like contacts between the processes, and pinocytic vesicles in the cytoplasm. The revealed ultrastructural signs indicate the histogenetic relationship of neurofibroma with cells of the perineurium of peripheral nerves.

[Electron microscopy diagnosis of soft tissue sarcoma]. / Elektronno-mikroskopicheskaia diagnostika sarkom miagkikh tkanei.

The results of electron microscopy studies of 20 soft tissue sarcomas difficult to diagnose-fibrosarcomas, malignant fibroxanthomas, leiomyosarcomas, rhabdomyosarcomas and malignant schwannomas, are reported. The tumor elements of each of these neoplasms showed rather typical ultrastructural features enabling us to reliably ascertain their histological origin.

[Epidermoid thymoma--a variety of thymus gland cancer]. / Epidermoidnaia timoma--raznovidnost' raka vilochkovoi zhelezy.

Epidermoid thymoma was referred to thymal malignancies after an evaluation of the data on its clinical course and microscopic structure. This tumor may be diagnosed preoperatively on the basis of an analysis of clinico-roentgeno-endoscopic data and findings of a cytological, histological and electron-microscopic examinations.