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Biomedical subjects

B Mackay

Publications and source records attributed to B Mackay.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Anaplastic thyroid carcinoma: an ultrastructural study of 10 cases.

Anaplastic carcinoma of the thyroid is an aggressive, rapidly fatal neoplasm that is generally believed to arise from the epithelium of the thyroid follicle. When differentiated carcinoma is not present, the diagnosis can be difficult and confusion with a sarcoma is frequently a problem. Ten anaplastic thyroid carcinomas have been examined by light and electron microscopy and compared with two biologically aggressive, solid follicular carcinomas. Ultrastructural study revealed evidence of epithelial differentiation in all the anaplastic carcinomas, confirming their origin from thyroid follicular cells. The study illustrates the value of electron microscopy in establishing the diagnosis of anaplastic carcinoma and in differentiating it from sarcoma.

Aged↗
PubMedDate not supplied

Adrenocortical carcinomas: an ultrastructural study of 22 cases.

Twenty-eight adrenocortical carcinomas from 22 patients have been studied by light and electron microscopy. The objective were to document the range of fine structure, to establish ultrastructural criteria for diagnosis, and to relate the morphology to the presence or lack of functional activity. The distinctive ultrastructural features of steroid-forming cells, smooth endoplasmic reticulum and tubular mitochondrial cristae, were only present in some cells of some of the cases. Sequential specimens (up to four) from a single patient demonstrated changes in the tumor cell morphology with progression, including marked accumulation of cytoplasmic glycogen.

Adrenal Cortex Neoplasms↗
PubMedDate not supplied

Ewing's sarcoma with neuroblastoma-like features.

Four tumors with the clinical and light microscopic features of Ewing's sarcoma contained cells that possessed to varying degrees ultrastructural features suggestive of neuroblastoma. These neoplasms were considered to be Ewing's sarcoma of bone by radiologic examination and on clinical grounds, and light microscopy was consistent with the diagnosis in every case. It is suggested that the ultrastructural morphology of Ewing's sarcoma is broader than had been supposed and that the presence of dendritic processes in a small cell tumor of bone should not exclude the diagnosis of Ewing's sarcoma.

Adolescent↗
PubMedDate not supplied

Ultrastructure of human tendon sheath and synovium: implications for tumor histogenesis.

Normal human tendon sheath and synovium were studied by scanning an transmission electron microscopy. The lining cells of the two tissues appear to be identical ultrastructurally. The most superficial cells (B-cells) possess long cytoplasmic extensions that clothe the membrane surface. Intermingled with deeper B-cells are the so-called A-cells, which have similar cytoplasmic features but lack long processes and instead have many filopodia. the frequent occurrence of intermediate forms indicates that the two cells form part of a morphologic spectrum. Comparison with cells of tumors that have been ascribed to synovium or tendon sheath (synovial sarcoma, epithelioid sarcoma, clear cell sarcoma) do not reveal any close similarities that might support a histogenetic relationship.

Cell Nucleus↗
PubMedDate not supplied

Hyaline inclusions in a synovial sarcoma following intra-arterial chemotherapy.

Hyaline inclusions were noted in cells of a typical synovial sarcoma following intra-arterial chemotherapy. Ultrastructural study revealed that the inclusions were cytoplasmic aggregates of intermediate filaments. Since the inclusions were not present in the tumor prior to treatment, it is suggested that they may have formed as a result of the infusion and that their presence may be an indicator of chemotherapeutic effect.

Cytoskeleton↗
PubMedDate not supplied

Ultrastructure of liver cell and bile duct carcinomas.

The primary concerns of the surgical pathologist examining a biopsy specimen are whether a particular neoplasm is originating within the liver or is metastatic and, if a primary, whether differentiation is toward liver cells or bile ducts. The present study was undertaken in the hopes of providing a broader concept of the ultrastructural spectrum of liver cell carcinoma (LCC) and a more precise understanding of the changes occurring in these neoplasms with dedifferentiation. The 20 liver cell carcinomas, 13 bile duct carcinomas (BDC), and 3 hepatoblastomas were studied ultrastructurally and the findings correlated with light microscopic sections stained by hematoxylin-eosin and the periodic acid-Schiff procedure with and without prior diastase digestion. Immunocytochemical staining for alpha 1-antitrypsin was carried out on selected tumors. Ultrastructural study can be useful in the distinction of LCC from BDC in the minority of cases in which this is difficult by light microscopy. While true mixed tumors appear to be uncommon, duct formation can be simulated by LCC cells. The extent to which electron microscopy will enable the pathologist to separate metastatic neoplasms in the liver from primary liver cell tumors depends on the relative ultrastructural features. Assessment of the value of electron microscopy as an aid to light microscopy in the histologic grading of LCC and BDC will require further study.

Adolescent↗
PubMedDate not supplied

The ultrastructure and histogenesis of male germ neoplasia with emphasis on seminoma with early carcinomatous features.

The range of ultrastructural morphology was studied in 107 male germ cell neoplasm to assess relationships among tumor subtypes and to consolidate diagnostic criteria. Eighty-three pure-pattern neoplasms including 47 seminomas, 26 embryonal carcinomas, 10 endodermal sinus tumors, and 24 mixed germ cell tumors were analyzed. In the seminoma category, 4 cases showing cell surface specialization in keeping with early carcinomatous transformation were noted. The finding suggested a closer link between seminoma and nonseminomatous germ cell tumors than had been traditionally recognized and was in keeping with other clinical, histologic, biochemical, and xenograft observations. Subtypes of nonseminomatous germ cell tumors also exhibited a continuum of ultrastructural morphology with some types such as embryonal carcinoma and endodermal sinus tumor often blending together. At a practical level, electron microscopy has been of value in selected differential diagnoses such as seminoma versus lymphoma.

Choriocarcinoma↗
PubMedDate not supplied

Ultrastructural and immunocytochemical observations on angiosarcomas.

Forty-seven angiosarcomas have been studied by light and electron microscopy. Neoplastic endothelial cells do not consistently display specific ultrastructural features, but certain aspects of the fine structure of the cells and their arrangement can be useful to establish or confirm the diagnosis. Experience with the common endothelial cell markers as diagnostic aids is briefly reviewed.

Factor VIII↗
PubMedDate not supplied

Peripheral neuroectodermal tumor of the chest wall in a 19-year-old female.

A small cell round tumor involving the chest wall of a 19-year-old female had features that by light microscopy were considered consistent with Ewing's tumor. At the ultrastructural level the cells contained small quantities of glycogen and had irregular dendritic processes with rare dense core granules and microtubules. Immunostaining for neuron-specific enolase was positive. The neoplasm is similar to reported cases of peripheral neuroectodermal tumor involving the chest wall of young patients.

Adult↗
PubMedDate not supplied

Myxoid malignant fibrous histiocytoma with erythrophagocytosis.

A tumor that formed multiple protuberant masses on the foot and leg of a 50-year-old white male had the light and electron microscopic features of a myxoid malignant fibrous histiocytoma. Ultrastructurally, the cells had some fibroblastic features. Extravasated erythrocytes were present throughout the tumor nodules and many had been phagocytosed by the tumor cells. Endothelial cell markers were negative.

Histiocytoma, Benign Fibrous↗
PubMedDate not supplied

Upper abdominal neoplasms: an introduction and selected references.

The organs in the upper half of the abdominal cavity can give rise to a highly heterogeneous collection of neoplasms that encompasses a broad spectrum of clinical features, light microscopic appearances, immunostaining properties, and fine structure. Because of the anatomic proximity of the viscera in this region, the differential diagnosis of an upper abdominal mass may include consideration of tumors that arise from the stomach, duodenum, liver, kidney, adrenal, and pancreas. There are many distinctive ultrastructural features among the various tumors that can be used effectively by the diagnostic electron microscopist, but it is also important to take into account the considerable overlap in fine structure that occurs among different tumors and among similar tumors from different organs. In the session on upper abdominal neoplasms, the electron microscopic characteristics of the common tumors of each viscus were reviewed before the presentation of individual case studies that incorporated original observations and illustrated some unusual entities. The selection of cases that follows is inevitably small and arbitrary, but the cases demonstrate the contribution that electron microscopy can make in the study of an upper abdominal mass and illustrate some of the similarities that can be encountered among tumors of different organs.

Abdominal Neoplasms↗