[Electron-microscopic changes of the brain in acute experimental peritonitis (AEP)].

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.

[Malignant fibrous histiocytoma of the larynx].

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.

[The fibroepithelial variant of basal-cell skin cancer (Pincus' "premalignant" fibroepithelioma)].

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.

[Alveolar soft tissue sarcoma].

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.

[Clinico-morphologic and electron microscopic characteristics of chemodectoma of the neck].

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.

[Unusual (epithelioid) leiomyoblastoma of the stomach].

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.

[Benign tumors of the peripheral nerve sheaths].

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.

[Epidermoid thymoma--a variety of thymus gland cancer].

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.

[Peripheral nerve ectomesenchymoma (neuroectomesenchymoma): a malignant tumor made up of neural crest elements].

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.

[Morphology and histogenesis of so-called fibrous mesothelioma (submesothelial fibroma)].

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.

[Morphology and histogenesis of soft tissue chordoid sarcoma].

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.

[Choledochotomy and the methods for its performance].

The authors have made 390 operations on ductus choledochus. Indications for choledochotomy were choledocholithiasis, jaundice, cholangitis and others. The ideal choledochotomy was fulfilled in 7,1% of cases as a completion of diagnostic manipulations on the duct.

[Histological and ultrastructural characteristics of Abricosov metastasizing tumor].

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.

[Pathological anatomy of thymus gland tumors].

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.

[Lymphogranulomatosis of the thymus gland ("granulomatous thymoma")].

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.