Extraovarian pelvic serous tumor with marked calcification.

We report two cases of low-grade extraovarian pelvic serous tumor. Each contained large numbers of psammoma bodies. The tumors belong to the small group of serous carcinomas that arise from the peritoneum. In both cases the tumor permeated the myometrial lymphatic vessels extensively. One patient is well eight years after surgery.

Nuclear morphologic and morphometric analyses of large noncleaved cell and immunoblastic non-Hodgkin's lymphomas.

Both morphologically and immunologically, non-Hodgkin's lymphoma (NHL) of the large cell type has been shown to be a heterogeneous category. However, the homogeneity of the nuclear parameters, particularly size and condensed chromatin organization, used to classify this subtype of NHL has not been investigated. In fact, objective morphologic techniques have not been systematically applied to verify the segregation of NHL on the basis of nuclear parameters, a concept common to all current classification systems. In this study morphometric image analysis was used to compare the nuclei in 20 specimens from NHLs of the large cell type with those in mantle zone and germinal center lymphocytes from lymph nodes with reactive hyperplasia. Results of the assessment of mean nuclear area in large cell lymphomas revealed that this class is also heterogeneous, with some of the specimens having a nuclear size in the upper range of that for normal small lymphocytes. In addition, in only a few of these specimens was the mean nuclear area within the range of that for fully transformed germinal center lymphocytes. The majority of large cell lymphomas have a nuclear size more characteristic of partially transformed lymphocytes in germinal centers. In addition to indicating inconsistencies in the current diagnostic criteria used in NHL classifications, the results indicate reasons for interobserver variations in clinicopathologic trials; the validity of nuclear size as a prognostic indicator and the biologic basis for classifying NHL as a reflection of normal lymphocyte transformation are also questioned. In terms of patient management, the classifications of NHL currently used require objective reappraisal.

Ultrastructure of poorly differentiated diffuse epithelial mesotheliomas.

In differentiating diffuse epithelial mesothelioma from metastatic adenocarcinoma in pleural and peritoneal biopsies, the number and form of microvilli and the amount and distribution of tonofilaments are thought to be the most useful criteria. This report details 5 cases of diffuse epithelial mesothelioma in which the characteristic fine structural features of neoplastic mesothelial cells were markedly modified. The majority or all tumor cells were poorly differentiated in electron micrographs, particularly with reduced prominence or absence of intermediate filaments, desmosomes, intracytoplasmic lumina, and microvilli. Immunohistochemistry revealed the absence of carcinoembryonic antigen and the presence of cytokeratin in all cases. Comparison with a better differentiated case suggests cytologic details that are useful in distinguishing the poorly differentiated type of epithelial mesotheliomas from adenocarcinoma. These include a mosaic pattern of closely associated tumor cells with a few long, narrow cytoplasmic processes lying parallel to adjacent plasma membranes, abundant cytoplasm with limited organelles usually having a polar arrangement, and nuclei with markedly disaggregated chromatin and prominent nucleolonemal-type nuclei.

Signet-ring cell variant of large cell lymphoma.

A diffuse, large cell lymphoma of palatine tonsil was found to contain a considerable number of enlarged tumor cells with prominent, hyaline, Russell body-type cytoplasmic inclusions displacing the nucleus peripherally and, thus, the morphologic features of signet-ring cell lymphoma. Immunoperoxidase staining revealed that the contents of the signet-ring cells were strongly positive for mu heavy chains and kappa light chains. Ultrastructurally, Russell body-type inclusions consisted of multiple, angulated, electron-dense crystalloids enclosed within expanded segments of rough endoplasmic reticulum.

Desmoplastic diffuse mesothelioma.

Twenty-seven cases of desmoplastic diffuse malignant mesothelioma (26 pleural, one peritoneal) are described. In 19 cases the tumor cell type was sarcomatous and in six others it was biphasic (malignant elements of both epithelial and mesenchymal aspect). There were only two cases where the tumor cell type was purely epithelial. The clinical course was often rapid; the mean survival period in 11 cases of purely sarcomatous type was 6.18 months. Only one case of purely sarcomatous type lived for more than 1 year as opposed to four of eight cases with an epithelial component. Metastases occurred more frequently in desmoplastic (60.1%) than in nondesmoplastic diffuse mesothelioma (42.5%). The tumor cell type (epithelial, mesenchymal) accompanying desmoplastic mesotheliomas and not the extent of desmoplasia determines their behavior. Desmoplasia in diffuse mesotheliomas is often the result of tumor cells assuming the functional capacity of fibroblasts and has frequently been confused with reactive fibrosis. Cytologic abnormalities, tissue infiltration, and foci of necrosis indicate the neoplastic nature of the process in most instances.

Papillary peritoneal tumors in women.

Twenty-five peritoneal tumors in women are described. All were partly or entirely of papillary or tubulopapillary structure and multifocal. Eight were unusually well-differentiated mesotheliomas. This appearance was associated with indolent behavior. In 10 cases the growth closely resembled serous papillary carcinoma, including the frequent presence of psammoma bodies, but the ovaries were free of primary tumor. The latter group of tumors progress rapidly and are thought to be derived from extraovarian mesothelium with müllerian potential. Four further cases showed some resemblance to ovarian papillary carcinoma. Only three tumors in the entire series (12%) closely resembled papillary or tubulopapillary diffuse malignant mesothelioma of the type that occurs in the pleural cavities in both sexes. The histopathologic spectrum of papillary tumors of peritoneum in women is extensive, and mesothelial tumors of the type known to be associated with asbestos are rare.

Angiofollicular lymphoid hyperplasia in an angiolipomatous mass.

A posterior mediastinal mass was composed of angiolipomatous and lymphoid tissue. The lymphoid tissue took the form of multiple nodules with appearances similar to those of angiofollicular lymphoid hyperplasia. The findings support the view that this form of lymphoid hyperplasia may be of hamartomatous nature.

A Canadian experience of the pathological diagnosis of diffuse mesothelioma.

A review of 398 pleural and peritoneal tumours suggests that diffuse mesothelioma was probably present in 50-60%. However, objective assessment was frequently impeded by serious deficiencies in data or material, which affect the diagnostic grading of cases seen by panels. Observer variation in diagnosis also remains a significant problem. The value of panels for diagnosis could be greatly increased by the provision of adequate data/material and by meetings.

Multiple primary malignant tumors: a rare combination in the stomach.

We have reported one case of a rare combination of multiple primary malignancies in the stomach, a leiomyosarcoma and an adenocarcinoma in a 72-year-old male. He also had a leiomyoma of the stomach and a cavernous hemangioma of the spleen. Since he has had two malignant and two benign tumors, it would appear that this patient has a tendency to develop neoplasia.