Biomedical subjects
Publications and source records attributed to B Mackay.
A case of renal angiomyolipoma with regional lymph node involvement is added to 20 cases previously reported. This represents the 11th case reported in a non-tuberous sclerosis patient. The electron microscopic features of the tumor are discussed and correlated with the light microscopic findings.
A case of adrenal cortical carcinoma composed of mitochondria-rich cells is reported. The cells contained condensed zones and loose whorls of smooth endoplasmic reticulum. Crystalline matrical inclusions were present in some of the mitochondria, whereas others contained round, homogeneous, dense matrical inclusions. Flow cytometry revealed a hyperdiploid stem line with a DNA index of 1.3.
The cytoplasmic granules in an adrenal pheochromocytoma were predominantly ovoid with loose-fitting limiting membranes and eccentrically positioned dense cores. The occurrence of similar granules in a recurrent tumor involving the organ of Zuckerkandl in a second patient suggests that the latter tumor should be designated an extraadrenal pheochromocytoma.
A case of islet cell tumor occurring in a patient with the multiple endocrine neoplasia type I syndrome is reported. Immunostaining for insulin was strongly positive in the tumor cells. Numerous dense-core granules of endocrine caliber were identified ultrastructurally. Morphometric analysis of the secretory granules in 20 islet cell tumors gave a granule size of 182 +/- 52 nm (mean +/- standard deviation).
A series of 24 small cell nasal tumors with neuroendocrine differentiation was studied by electron microscopy, and the numbers of secretory granules and cell junctions were assessed. To investigate the relationship between the extent of dendrite formation and the behavior of the tumors, the size of the tumor cells and the area occupied by dendritic processes were determined for each tumor by morphometric analysis performed on low-magnification electron micrographs. A positive correlation was demonstrated between the dendritic area index and the survival of the patients (P = 0.017). Neither the number of secretory granules nor the frequency of cell junctions was prognostically significant.
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Ultrastructural observations on 60 fibrosarcomas are presented. Myofibroblastic differentiation was found in 33 tumors but usually in scattered cells. Diffuse aggregates of nonspecific intermediate filaments were present in a number of the tumors. Electron microscopy is useful to distinguish fibrosarcoma from other soft tissue sarcomas that it can resemble by routine light microscopy, and its value is enhanced when selected immunocytochemical procedures are also performed.
An unusual, benign, spindle cell peripheral nerve sheath tumor (PNST) is reported that on ultrastructural examination was composed only of perineurial cells. The neoplastic cells showed positive immunoreactivity for S-100 protein and negative immunoreactivity for epithelial membrane antigen; this is not the expected immunophenotype of a perineurioma. Continued examination of benign PNSTs using electron microscopy and immunohistochemistry has the potential to reveal additional variations in the cellular composition and immunophenotype of these soft tissue tumors. PNSTs such as the one described will renew the debate about the cytogenesis of the perineurial cell and its role in PNSTs.
We have demonstrated the value of electron microscopy in the study of ten uncommon lung tumors. Ultrastructural examination contributes toward the accurate classification of unusual lung tumors, and may clarify their histogenesis.
Primary malignant melanoma of the urinary bladder is a rare tumor. A case in a 34-year-old man who presented with gross hematuria is reported. Cystoscopic biopsy showed a mixed spindle cell and clear cell neoplasm with focal pigmentation. The tumor cells were immunoreactive for S-100 protein and HMB-45. The patient did not have a history of melanoma, and clinical and radiologic work-up did not reveal other lesions, so a partial cystectomy and pelvic lymphadenectomy were performed. The tumor formed an ulcerated mass that extended into the perivesicular fat. Microscopically, the tumor was composed predominantly of clear cells in sheets or small nests. A solitary metastatic focus was present in 1 of 25 pelvic lymph nodes. Ultrastructurally, the tumor cells were characterized by irregular nuclear contours, complex nucleoli, abundant cytoplasmic glycogen, and premelanosomes.
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Twenty-six ependymomas were studied by light and electron microscopy. By electron microscopy, the acellular zones around small vessels in light microscopic sections were seen to be composed of large numbers of closely packed, filament-rich, cytoplasmic processes ringing small vessels. Lumina were consistently present but many of them were too small to be seen by light microscopy. The lumina contained slender, curving microvilli and variable numbers of cilia. Their bordering cells were connected by unusually long tight junctions. Electron microscopy can be useful to establish or confirm a diagnosis of ependymoma when the light microscopic appearance is atypical, or when the tumor arises in an unusual location. The clinical data on the 26 cases has been reviewed; follow-up information was available on 23 patients.
The ultrastructural features of 30 adrenal cortical carcinomas have been reviewed and compared with those seen in adrenal cortical adenomas, adrenal cortical hyperplasia, and the normal cortex. A broad range of ultrastructural appearances was found among the carcinomas, but the differences were mainly in the amount of cytoplasmic lipid, number of lysosomes, and quantity and architecture of the mitochondria and endoplasmic reticulum. Structural variants among the carcinomas included lipid-rich, oncocytic, and glycogen-rich cells. Electron microscopy can be extremely useful in differential diagnoses that include adrenal cortical carcinoma.
Ultrastructural evaluation of endomyocardial biopsy specimens is a sensitive and effective method with which to detect and quantitate cardiotoxicity produced by anthracylines. The procedure and grading system used at the M.D. Anderson Cancer Center are described, and some of the pitfalls that may be encountered by the electron microscopist are reviewed.
A nodule from the scalp of a 14-year-old boy was diagnosed by light and electron microscopy as a meningioma. There was no evidence of an intracranial lesion or involvement of the bone of the skull. The tumor was excised but recurred and metastasized to lung and chest wall.
A 73-year-old white woman developed multiple cutaneous nodules that fluctuated in size and occasionally regressed. The tumor cells infiltrating the dermis were histiocytic by light microscopy, marker studies, and electron microscopy. Similar cells were present in a bone marrow biopsy specimen. A diagnosis of true histiocytic lymphoma was made. The case illustrates some of the problems that may arise in evaluation of clinical and pathologic findings in a patient with a proliferative disorder of histiocytes and demonstrates the contribution that electron microscopy can provide in establishing the diagnosis.
Parachordoma is a soft tissue tumor that has a light microscopic appearance similar to that of chordoma, and the immunostaining properties of the two tumors are alike. The clinical findings and light microscopy of one case of parachordoma are presented together with ultrastructural observations on this tumor and parachordomas from five additional patients.
A case of extraskeletal myxoid chondrosarcoma with intracisternal microtubules is presented. The microtubules were generally straight, parallel, closely packed, and evenly spaced, but they did not form geometric arrays. Aggregates of stromalike myxoid material were present in the cisternae and the adjacent cytoplasm. Microtubules were never found within the cytoplasm. A similar ultrastructural appearance was seen in 4 of 10 other examples of extraskeletal myxoid chondrosarcoma.