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Biomedical subjects

B Mackay

Publications and source records attributed to B Mackay.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Pigmented carcinoma of the breast: an ultrastructural study.

A pigmented skin lesion on a breast removed for carcinoma resembled melanoma by routine light microscopy, but correlation with immunohistochemistry and electron microscopy established that carcinoma cells within the upper dermis were intermingled with a proliferation of non-neoplastic melanocytic cells. Ultrastructurally, the tumor cells possessed desmosomes and intracytoplasmic lumina and mature melanosomes were present in their cytoplasm. The melanocytic cells were identified as melanocytes or melanophages, and it was concluded that the tumor in the skin was a passively pigmented carcinoma and not a melanoma or metaplastic breast carcinoma.

Biomarkers, Tumor↗
PubMedDate not supplied

Brenner tumor of the ovary: a comparative immunohistochemical and ultrastructural study with transitional cell carcinoma of the bladder.

Because of a fancied light microscopic resemblance to transitional epithelium (urothelium), Brenner tumor (BT) of the ovary is commonly described as a transitional cell neoplasm. An inability to detect a great deal of similarity between the two at the ultrastructural level prompted this electron microscopic study comparing 3 benign Brenner tumors with normal urothelium and 6 transitional cell carcinomas (TCC) of varying histologic grade from the urinary bladder. To complement the ultrastructural observations, the immunophenotype of 8 benign BTs was evaluated together with that of 12 TCCs of the bladder using antibodies to thrombomodulin (TM), cytokeratin 20, cytokeratin 7, and carcinoembryonic antigen (CEA), all of which have been shown to react with TCCs of urothelial origin. At the ultrastructural level, there was only limited evidence of a morphologic likeness between the epithelial cells of BTs and those of the benign or neoplastic urothelium. The immunophenotype of the two tumors also differed significantly in that there was no reactivity for TM or cytokeratin 20 in the BTs, while these markers were expressed in the TCCs. Both BTs and TCCs were positive for cytokeratin 7 and may express CEA.

Aged↗
PubMedDate not supplied

Acinar cell carcinoma of the pancreas.

Four cases of acinar cell carcinoma of the pancreas are reported. An acinar cell carcinoma can resemble an islet cell tumor by routine light microscopy but the two differ considerably in their fine structure and immunostaining properties. Although cells of both tumors contain numerous dense-core granules, their size ranges are different, and atypical forms occur in the acinar cell tumors, including elongated bodies filled with filaments. Many mitochondria-rough endoplasmic reticulum complexes were present in one tumor. In a liver metastasis, nests of endocrine cells were discovered amid the groups of acinar cells, and some of the endocrine granules contained rectangular cores.

Adult↗
PubMedDate not supplied

Malignant fibrous histiocytoma: an ultrastructural perspective.

Malignant fibrous histiocytoma is a frequent diagnosis, but the relationship of the tumors to histologically similar soft tissue neoplasms is controversial. In this study, 157 examples representing the 4 main subtypes were reviewed by light microscopy and each tumor was studied with the electron microscope. Immunohistochemical stains were performed on 77 tumors. Electron micrographs on 100 fibrosarcomas were reviewed for comparison. Malignant fibrous histiocytomas often closely resemble fibrosarcomas at the ultrastructural level and differences between the two are generally of degree only. Evidence for true histiocytic differentiation was not found. The immunohistochemical results did not contradict the authors' impression from electron microscopy that malignant fibrous histiocytoma forms part of the histologic spectrum of tumors of fibroblasts.

Diagnosis, Differential↗
PubMedDate not supplied

Glycogen-rich mesothelioma.

A glycogen-rich epithelial mesothelioma is described. This variant is uncommon, but important to recognize since it is readily confused on routine light microscopy with other clear cell tumors involving the pleura. Ultrastructural and immunohistochemical studies can be helpful in establishing the correct diagnosis. Significant recent advances in the immunohistochemistry of epithelial mesothelioma are briefly reviewed.

Aged↗
PubMedDate not supplied

Granular cell tumor: a review of the pathology and histogenesis.

As the name suggests, the histogenesis of the granular cell tumor is uncertain, but this intriguing neoplasm has occasioned much speculation and controversy since its description in 1926 as a myoblastoma. Though ubiquitous in its anatomic location, it is usually small, solitary, benign, and readily recognized by routine light microscopy, and questions concerning it are principally academic. However, a small number of cases are malignant and they can be difficult to identify in paraffin sections. The combined input from immunohistochemistry and electron microscopy has greatly clarified understanding of the morphology of this lesion and both methods are helpful when the differential diagnosis is a problem. The cell of origin is still undecided, and although distinct neural features argue for Schwannian origin, the noncommittal term granular cell tumor continues to be appropriate.

Adult↗
PubMedDate not supplied

Intracristal crystalline inclusions in mitochondria of a neuroblastoma.

Mitochondrial inclusions were found in a neuroblastoma of the paranasal tissues in a 23-year-old male. They were present in almost every cell, were intracristal in location, and had a helical substructure. They are similar to previously reported intramitochondrial crystalline inclusion bodies.

Adult↗
PubMedDate not supplied

Signet-ring cell lymphoma.

In a small cleaved, follicular center cell (poorly differentiated) lymphoma the majority of the cells appeared vacuolated by light microscopy. This is an example of the recently described signet-ring cell lymphoma. Immunoperoxidase staining demonstrated that the cells contained IgG/k. Ultrastructural observations indicated that small vacuoles coalesce to form the large vacuoles, which contain microvesicles approximately 50 nm in diameter.

Female↗
PubMedDate not supplied

Intracisternal tubules in human melanoma cells.

Aggregates of parallel microtubules have been found within cisternae of the rough endoplasmic reticulum in cells of six human metastatic melanomas. The tubules have a uniform diameter and regular spacing and in longitudinal sections can be seen to possess a fine periodicity. They are compared with tubuloreticular inclusions reported in other cells.

Adult↗
PubMedDate not supplied

Oncocytic carcinoid tumor of the lung.

A case of bronchial carcinoid tumor is reported in which a marked degree of transformation to mitochondrion-rich cells (oncocytes) was present. Ultrastructural observations demonstrated a transition between the two cell types, and revealed an alteration in mitochondria suggestive of a degenerative change in these organelles.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMedDate not supplied

Neuroendocrine (Merkel cell) carcinomas of the skin: an ultrastructural study of nine cases.

Nine neuroendocrine tumors of the skin were examined by light and electron microscopy. The patients (7 males and 2 females) had an average age of 57 years. Seven tumors were located in the head and neck region. Light microscopic examination showed sheets of cells. In 4 cases, a tendency to form small groups of cells was observed. Contact with the epidermis was seen in only 2 cases. The dominant ultrastructural feature was the presence of cytoplasmic processes that contained membrane-bound granules 100-200 nm. Three tumors recurred locally, and in 7 patients, regional nodal metastases occurred. Three patients died of disseminated disease.

Aged↗
PubMedDate not supplied

Malignant smooth muscle tumors of the gastrointestinal tract: an ultrastructural study of 20 cases.

Twenty malignant soft tissue tumors arising from the stomach or intestine have been studied by light and electron microscopy, and the clinical records of each patient reviewed. The tumors were all considered to be of smooth muscle origin by light microscopy: Ten were spindle cell and ten were epitheloid neoplasms. By electron microscopy, only five tumors possessed smooth muscle features. A sequence of dedifferentiation could be traced among the remaining cases, indicating that the epitheloid tumors are of smooth muscle derivation. Awareness of the broad spectrum of fine structure displayed by these neoplasms will facilitate their ultrastructural identification.

Adult↗