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B W Scheithauer

Publications and source records attributed to B W Scheithauer.

At least 433 records · Page 24Linked to original sources
PubMedDate not supplied

Pituitary carcinoma: an ultrastructural study of eleven cases.

Pituitary carcinomas are very rare. Defined as adenohypophysial tumors that undergo craniospinal and/or systemic metastasis, most are PRL- or ACTH-producing. Their ultrastructural features, particularly relative to benign adenomas of similar functional type, have not been sufficiently explored. Eleven cases of immunohistochemically characterized pituitary carcinoma with documented cerebrospinal and/or systemic metastases were collected from various institutions and studied by transmission electron microscopy. The tumors were surgically removed from 7 women and 4 men ranging in age between 28 and 74 years (mean, 50 years). All were endocrinologically functioning. Six tumors secreted PRL; three were ACTH-producing; one each was GH/PRL- and TSH-producing. The patients with the ACTH-producing tumors had all presented with Cushing's disease and two of them had undergone adrenalectomy (Nelson syndrome). In most cases significant cellular atypia and mitotic activity were observed. In terms of morphologic features of functional differentiation, electron microscopy revealed that in 9 cases the tumor cells maintained at least some ultrastructural markers of their basic phenotype. A unique feature in 2 ACTH carcinomas was the variable admixture of smooth endoplasmic reticulum with intermediate (cytokeratin) filaments. In 2 cases, both PRL-producing carcinomas, the cell type comprising the tumor could not be identified on an ultrastructural basis alone. Ultrastructural investigation of pituitary carcinomas confirms their endocrine nature and, in most but not all cases, reveals their functional differentiation. Despite the diagnostic utility of electron microscopy in the assessment of these rare tumors, the distinction of pituitary carcinoma from pituitary adenoma cannot be firmly made on ultrastructural grounds alone.

Adenoma↗
PubMedDate not supplied

Ultrastructural features of apoptosis in human pituitary adenomas.

Although several recent studies deal with various molecular aspects of apoptosis, or programmed cell death, very little information is available on the ultrastructural changes associated with apoptosis in the adenohypophysis and its role in the regulation of pituitary adenoma growth and progression. This paper describes the distinct ultrastructural sequences that develop during the various phases of the apoptotic process. The study is based on the ultrastructural investigation of more than 8,000 surgically removed pituitary biopsies, which were examined by histology and immunocytochemistry for diagnostic purposes. No apoptosis was found in normal adenohypophysis and it is also a rare event in pituitary adenomas. When present, adenomatous adenohypophysial cells exhibit common and characteristic apoptotic changes. The ultrastructural alterations of membraneous organelles associated with apoptosis are similar to those previously reported in other tissues. It is noteworthy that apoptosis is clearly distinguishable from the ubiquitous dark cells denoting the common way of cell death. The findings suggest that apoptosis in pituitary adenomas is not a random event. Practically every specimen containing multiple apoptotic cells represents corticotroph adenoma. Occasional examples occur in lactotroph or gonadotroph adenomas. Although electron microscopic specimens are admittedly small, the large number of investigated cases gives credence to the observations.

Adenoma↗
PubMedDate not supplied

Ultrastructural features of pleomorphic xanthoastrocytoma: a comparative study with glioblastoma multiforme.

Eighteen tumors (15 cases) were ultrastructurally examined and compared to 11 examples of glioblastoma multiforme (GBM) [to determine the cellular nature of pleomorphic xanthoastrocytoma (PXA).] PXA, as well as GBM, were principally composed of pleomorphic astrocytes containing numerous intermediate filaments. Lipid droplets, lysosomes, and basal laminas were more numerous and fully developed in PXA, but were not specific to the tumor. Aggregates of secondary lysosomes, light microscopically evident as eosinophilic granular bodies, and ribosome-lamella complexes were exclusively seen in PXA. Also noted in PXA were centrioles, occasional Rosenthal fibers, hemidesmosomes in small number, rudimentary cell junctions, and interstitial calcifications. In addition to astrocytic constituents, 20% of PXA contained cells with neuronal features, as evidenced by the presence of dense-core granules, microtubules, and clear vesicles. In contrast, GBMs consisted solely of astrocytic cells. In the present study, the salient ultrastructural findings of PXA were largely degenerative in nature, including numerous lipid droplets and secondary lysosomes, as well as basal laminas, ribosome-lamella complexes, and occasional neuronal differentiation. The presence of basal lamina does not necessarily imply a histogenetic derivation from subpial astrocytes, in that it is also a common feature of GBM. Given the occurrence of biphenotypic, glioneuronal differentiation in some cases, PXA may be derived from a neuroepithelial stem cell. The authors conclude that PXA is fundamentally an astrocytic tumor, albeit one with a significant tendency to undergo neuronal differentiation.

Astrocytes↗
PubMedDate not supplied

Pituitary adenoma in Carney complex: an immunohistochemical, ultrastructural, and immunoelectron microscopic study.

First described in 1985, Carney complex is a rare, heritable disorder featuring abnormal skin pigmentation, cardiac and cutaneous myxoma, melanotic schwannoma of psammomatous type, and endocrine abnormalities, including pituitary adenomas. Patients with the latter present with elevated growth hormone (GH) levels and acromegaly or gigantism. Prolactin (PRL) elevation may also be seen. The authors have investigated 2 resected pituitary adenomas from patients with Carney complex. One, a 19-year-old female acromegalic with elevated GH, IgF-1, and PRL levels, had a mammosomatotroph adenoma immunoreactive for GH and PRL. Ultrastructurally, GH and PRL were present in the same secretory granules. The second patient, a 27-year-old acromegalic, had a sparsely granulated GH cell adenoma that by immuno-electron microscopy revealed GH immunoreactivity only. The lack of morphologic similarity between the 2 adenomas indicatesthat pituitary tumors in patients with Carney complex may not exhibit the same phenotype.

Abnormalities, Multiple↗
PubMedDate not supplied

Fibrous meningioma with tyrosine-rich crystals.

A 58-year-old African-American woman presented with a 6-month history of headaches. A magnetic resonance imaging scan of the head revealed a 5-cm, enhancing dura-based mass in the left parietal region. The variably cellular tumor was composed of uniform spindle cells associated with intercellular collagen and numerous radially arranged "petal-shaped" clusters of eosinophilic crystals. The tumor was diagnosed by light microscopy as a fibrous meningioma. Ultrastructural examination disclosed cells with complex interdigitating processes connected by desmosome-like cell junctions, abundant intercellular collagen fibers, and prominent, densely osmiophilic crystals featuring radiating teardrop shaped petals emanating from a central core. A positive Millon reaction showed these crystals to consist at least in part of tyrosine. By morphology, histochemistry, and ultrastructure, the crystals resembled tyrosine-rich crystals occurring in salivary gland tumors. This is the first report of a fibrous meningioma containing tyrosine-rich crystals.

Crystallization↗
PubMedDate not supplied

Neural and neuroendocrine tumors of the larynx.

Benign and malignant neural and neuroendocrine tumors of the larynx are uncommon enough that knowledge about them is sparse, coming from single case reports and literature reviews. We have reviewed the clinical behavior, pathologic findings, treatment, and outcome in 42 patients seen at one institution from 1907 to 1986. In some cases, electron microscopy or immunocytochemistry, or both, may be needed to reach the correct diagnosis. Treatment is largely determined by the histopathologic features, size, and location of the tumor. The most common sites are the supraglottic region and posterior larynx. Most tumors are treated by conservation surgery, including transoral excision; however, some are aggressive and require larger surgical procedures, including wide-field laryngectomy and complete neck dissection.

Adolescent↗
PubMedDate not supplied

Pituitary adenomas producing growth hormone, prolactin, and one or more glycoprotein hormones: a histologic, immunohistochemical, and ultrastructural study of four surgically removed tumors.

The morphologic features of four pituitary adenomas, removed from 2 men and 2 women between 31 and 62 years of age, are reported. The tumors contained growth hormone (GH), prolactin (PRL), and one or more glycoprotein hormones--usually thyrotropin (TSH). Three tumors were associated with acromegaly and one with hyperprolactinemia. Hyperthyroidism was not evident in any of the patients. In the tumors of acromegalic subjects, GH-containing cells were the most numerous, whereas PRL cells were dominant in the adenoma accompanied by hyperprolactinemia. Electron microscopy revealed plurimorphous tumors comprised of various proportions of morphologically different cell types: densely granulated GH cells, TSH-like cells, and the less common mammosomatotrophs and PRL cells. It is suggested that pituitary adenomas producing GH, PRL, and glycoprotein hormones derive from the same precursor; their immunocytochemical profile, fine structural appearance, and endocrine function may depend on the degree and direction of the cellular differentiation.

Adenoma, Acidophil↗
PubMedDate not supplied

Ultrastructural spectrum of hemangiopericytoma: a comparative study of fetal, adult, and neoplastic pericytes.

Since ultrastructural examination is often employed to assess controversial soft tissue tumors, it is important to be aware of the range of differentiation assumed by the tumor cells in hemangiopericytomas. For this purpose, 35 examples (10 localized to the central nervous system and 25 located peripherally) were examined ultrastructurally, and, of these, 20 cases were also studied immunohistochemically for the presence of intermediate filaments and muscle-specific actin. Based on cytologic characteristics evident by electron microscopy, tumor cell differentiation was classed as pericytic (32%), myoid (8%), nondescript (48%), fibroblastic (4%), and histiocytic (8%). Vimentin was the only intermediate filament expressed in the normal pericytes of human fetal and adult tissues and in the neoplastic pericytes of all of the hemangiopericytomas. Muscle-specific actin was present in normal pericytes, but only focally in two of the hemangiopericytomas. In various combinations basal lamina-like materials, cytoplasmic processes, cytoplasmic filaments, discrete basal lamina, and poorly formed intercellular junctions were the most frequently noted features of the tumor cells in hemangiopericytomas, whether central or peripheral, and they assist, along with the organizational relationship of tumor cells and capillaries, in distinguishing this lesion from other soft tissue sarcomas.

Actins↗
PubMedDate not supplied

Pineal germinomas and testicular seminoma: a comparative ultrastructural study with special references to early carcinomatous transformation.

We have investigated the ultrastructural characteristics of 16 cases of pineal germinomas and compared them with those of 18 cases of testicular seminomas. Glandular differentiation of tumor cells was found in both though it was more consistently noted in pineal germinomas than in testicular seminomas. This feature was interpreted to represent early carcinomatous transformation of germinoma cells. It not only explains the difficulties occasionally encountered in distinguishing germinoma and its anaplastic variant from embryonal carcinoma, but also has implications for our understanding of germ cell neoplasia, particularly the place of germinoma/seminoma in the nosology of such tumors.

Brain Neoplasms↗
PubMedDate not supplied

Colloid cyst of the third ventricle: a comparative ultrastructural study of neuraxis cysts and choroid plexus epithelium.

Thirteen colloid cysts (CC), four Rathke cleft cysts (RCC), three follicular cysts of normal pituitary gland (FCP), four enterogenous cysts (EC), three normal choroid plexi (CP), three choroid plexus papillomas (CPP), and several samples of normal bronchial mucosa and ependyma were studied by electron microscopy. The ultrastructure of most of the CC was indistinguishable from that of RCC, FCP, EC, and normal bronchial mucosa in demonstrating nonciliated and ciliated epithelial cells, goblet cells, basal cells, and intermediate forms, some showing evidence of early squamous differentiation. Two CC displayed mostly squamous differentiation, and one contained basally situated cells resembling myoepithelial cells. Although the RCC and FCP displayed features similar to those of CC, they also contained cells with electron-dense granules indicating pituitary hormone production and scattered cells showing oncocytic change. EC were lined by either squamous cells or mucin-producing columnar cells. Every CC, RCC, FCP, and EC contained cells covered by glycocalyx. In contrast to aforementioned lesions, ependymal lining, CP, and CPP were composed of a single cell type, one with numerous villi, few cilia, and no signs of keratinization, mucin production, or glycocalyx coating. It is concluded that the ultrastructural properties of CC are the same as those of cysts of endodermal or ectodermal origin and of respiratory mucosa. No ultrastructural similarities were observed between CC and normal or neoplastic neuroepithelium. These ultrastructural findings support the concept of an enterogenous origin of colloid cysts and highlight their similarity to RCC.

Cerebral Ventricles↗
PubMedDate not supplied

Cushing's syndrome secondary to olfactory neuroblastoma.

A case of olfactory neuroblastoma in a 36-year-old woman who presented with florid Cushing's syndrome is reported. A nasal polyp, which proved to be an olfactory neuroblastoma, was resected. The procedure was followed by complete remission from the endocrinologic abnormalities. Postoperatively, the patient was well for 5 years until recurrence of both Cushing's syndrome and the nasal polyp was noted. Following combined transnasal-transcranial resection of the tumor, which extended into the anterior cranial fossa, the patient again experienced complete remission of Cushing's syndrome. Immunohistochemistry showed the tumor to be positive for neuron-specific enolase, synaptophysin, chromogranin, adrenocorticotropic hormone, beta-endorphin, and S-100 protein. Electron microscopy revealed neuritic processes containing microtubules and neurosecretory granules. This is the first reported case of Cushing's syndrome secondary to olfactory neuroblastoma.

Adult↗
PubMedDate not supplied

Pineal parenchymal tumors: an ultrastructural study with prognostic implications.

The pineal gland is host to a spectrum of neoplasms. Those considered to be derived from or differentiating toward pineal parenchymal cells are rare. Traditionally, pineal parenchymal tumors (PPTs) have been divided into 3 types: pineocytomas, pineoblastomas, and mixed or transitional tumors. Their characterization has been far from adequate and no firm diagnostic criteria, light microscopic or ultrastructural, have been established. In an attempt to provide more precise prognostic diagnostic criteria, we undertook a detailed ultrastructural analysis of 17 PPTs and found them to exhibit light microscopic and ultrastructural features strikingly similar to those of pineal parenchymal cells in varying stages of development, ranging from undifferentiated primitive neuroepithelial cells to mature pineal parenchymal cells. We endorse classification of PPTs based on a combination of their light microscopic and ultrastructural features. Accordingly, PPTs can be divided into three categories: 1) pinealoblastoma, 2) PPTs of intermediate or mixed differentiation, and 3) pineocytoma, a tumor of mature-appearing pineocytes. In keeping with this classification, our 3 pinealoblastomas behaved as highly malignant tumors. A correlation of morphology and prognosis was less evident between intermediate tumors and pineocytomas, perhaps the result of considerable variation in surgical and other therapies. Evidence of neurosensory differentiation, a feature noted to a varying extent in all but the pineoblastomas, included club-shaped "nerve endings" in 7 tumors, small numbers of dense core granules in 8, clear vesicles in 7, and structures suggestive of synapses in 4. With the exception of 3 undifferentiated PPTs or pinealoblastomas lacking nerve endings, all pineocytomas exhibited some combination of these markers of neuronal specialization. In that the ultrastructural features of these PPTs were more indicative of their aggressiveness than was their degree of light microscopic differentiation or grade, we consider electron microscopy a useful adjunct, not only in diagnosis but also in therapeutic decision-making and prognostication.

Adolescent↗
PubMedDate not supplied

Aggressive small cell tumor of the skull base.

A 40-year-old Black man presenting with increasing nasal discharge of bloody, mucoid pus as well as nasal obstruction over a 2-month period is described. Magnetic resonance imaging of the skull showed a tumor eroding through the skull base into the clivus and extending into the sphenoid sinus. Endoscopy of the sphenoid sinus demonstrated a polypoid mass extending into the posterior choanae. The lesion was partially resected. Histologic evaluation showed a cellular small blue cell tumor punctuated by bland, epithelial-lined microcysts. Electron microscopy revealed epithelial cells with abundant rough endoplasmic reticulum and electron-dense membrane-bound endocrine granules, some undergoing misplaced exocytosis. Immunohistochemical evaluation demonstrated cytoplasmic reactivity for neuron-specific enolase, synaptophysin, and prolactin. Stains for leukocyte common antigen, HMB-45, desmin, cytokeratin, chromogranin, and the remaining spectrum of pituitary hormones including growth hormone, corticotropin, luteinizing hormone, follicle-stimulating hormone, and thyrotrophic hormone were negative. In contrast, the epithelium lining the cysts was cytokeratin positive and synaptophysin negative. This ostensibly small cell tumor therefore represented a remarkably extensive and aggressive prolactin cell adenoma with unusual light microscopic features. Characterization of the lesion required electron microscopy and further confirmation by immunocytology. The distinction of pituitary adenomas and particularly of prolactin cell tumors from other adenoma types and from other small cell lesions markedly affects therapy and patient prognosis.

Adult↗
PubMedDate not supplied

Pituitary adenoma with neuronal choristoma (PANCH): composite lesion or lineage infidelity?

Fifteen cases of the rare association of pituitary adenoma and neuronal choristoma (PANCH) were investigated by histology, immunohistochemistry, and electron microscopy. Acromegaly was apparent clinically in 11 patients and was equivocal in 1, and 3 lesions appeared to be nonfunctioning. Histology revealed various proportions of chromophobic PA and nervous tissue consisting of neuronlike cells and neuropil. Immunohistochemistry documented growth hormone (GH) in every PA, including those unassociated with clinical acromegaly. In contrast, the NCH component showed no consistent immunohistochemical profile. Most frequent reactivities were for the pituitary hormone alpha subunit, thyroid-stimulating hormone, and GH, whereas only a few cases displayed scattered positivity for GH-releasing hormone. Low-molecular weight keratin tested positive in PAs and in a few cells and processes of an NCH. A few fibrous bodies were immunoreactive for neurofilament protein. Electron microscopy revealed sparsely granulated GH cell adenoma, neurons, and neuropil. Cells intermediate between PA and neurons were numerous in 1 lesion. The present morphologic findings as well as lack of GH cell hyperplasia and the consistent association of NCH with but one type of PA do not support the causative role of NCH in the initiation of PA, as proposed previously. It appears that NCH is the result of neuronal differentiation within sparsely granulated GH cell adenomas.

Adenoma, Chromophobe↗
PubMedDate not supplied

Mixed ependymoma-neuroendocrine tumor of the lateral ventricle.

A histologically unique glioneuronal neoplasm occupying the lateral ventricle of a child was immunohistochemically and ultrastructurally characterized. Its principal component exhibited the characteristic features of ependymoma, whereas a minor population of neuroendocrine cells, occurring singly and in small clusters, lay scattered throughout the ependymoma component. Yet another unusual finding was the presence of numerous elastic fibers within the extracellular matrix. This tumor is considered to represent a true mixed neoplasm consisting of ependymal and neuroendocrine elements.

Cerebral Ventricle Neoplasms↗
PubMedDate not supplied

Cytomorphology of subependymal giant cell astrocytoma.

The cytomorphology of three subependymal giant cell astrocytomas (SEGA) is described. The tumors occurred in the left lateral ventricle of three males with tuberous sclerosis. The often-polarized spindle and epithelioid tumor cells possessed dense eosinophilic cytoplasm, eccentric nuclei and visible, occasionally prominent nucleoli. In addition, they displayed thick or hairlike processes and had a distinct tendency to form cohesive clusters as well as pseudorosettes. Occasional binucleate and multinucleate cells, as well as "strap" cells and nuclear cytoplasmic inclusions, were further features of this unique tumor. In cytologic terms the principal differential diagnostic considerations include gemistocytic astrocytoma, giant cell glioblastoma and ependymoma. Since, in isolation, SEGA may represent a "forme fruste" of tuberous sclerosis and since patients with tuberous sclerosis may have brain tumors other than SEGA, it is of diagnostic importance to recognize the cytomorphologic features of this essentially benign brain tumor.

Astrocytoma↗
PubMedDate not supplied

Pituitary adenoma: a DNA flow cytometric study of 192 clinicopathologically characterized tumors.

A clinically, immunohistochemically and ultrastructurally characterized series of 192 pituitary adenomas was analyzed for DNA content by flow cytometry. Results were assessed not only relative to tumor immunotype, size, and invasiveness, but also with frequency of recurrence. Case selection was non-random; males predominated (1.8:1) and the ratio of macro-to-microadenomas was 4.2:1. Female patients were slightly younger and, in all adenoma categories, less often had invasive tumors: PRL (15%/30%), ACTH (17%/44%), LH/FSH (8%/27%) and null cell adenomas (0%/27%). With the exception of prolactin cell adenomas, similar proportions of macroadenomas and invasive tumors in all tumor subtypes were diploid and non-diploid. Prolactin adenomas differed in that tumors of males showed a high rate of non-diploidy (65%); such tumors were predominantly macroadenomas, but only 28% were invasive. Among GH-containing tumors 78% were macroadenomas, 40% were nondiploid, and the frequency of invasive macroadenomas was higher (49%) than in PRL tumors (21%). ACTH adenomas were mainly microadenomas (81%), their rate invasion (29%) and of non-diploidy being low (14%). Among "non-functioning" (LH/FSH, null cell adenomas), LH/FSH-producing tumors were all macroadenomas, but with low rates of invasion (23%) and non-diploidy (9%). Null cell adenomas, nearly all macroadenomas, had similar low invasion rate (21%), but were more often non-diploid (39%). In all adenoma subgroups S-phase fractions were higher in non-diploid adenomas by an overall ratio of 2.1:1. Prolactin adenomas showed the highest (15.2%) and LH/FSH adenomas the lowest (5.6%) mean S-phase fraction. When compared to long-term follow-up, neither this parameter nor ploidy correlated with tumor size or invasiveness. Lastly, long-term follow-up showed ploidy to be an unreliable predictor of tumor persistence or recurrence.

Adenoma↗