Ultrastructure of three Hürthle cell tumors of the thyroid

Mitochondria-rich normal, metaplastic, and neoplastic cells show overexpression of the epitope H recognized by the monoclonal antibody H

The epitope H contains an O-linked N-acetylglucosamine (O-GlcNAc) residue in a specific conformation and/or environment recognized by monoclonal antibody H (mAbH). We have previously shown that the epitope H is present in more than one polypeptide and in various types of normal and pathological cells. In the present study, we focused on mitochondria-rich normal, metaplastic, and neoplastic cells, prompted by our recent immuno-electron microscopy findings that mAbH clearly stains the mitochondria of breast epithelial cells in infiltrating ductal breast carcinomas and fibroadenomas. The indirect immunoperoxidase method was applied using the mAbH to investigate the distribution of the epitope H in mitochondria-rich normal cells and in metaplastic and neoplastic oncocytic cells. Immunohistochemical staining for the mAbH was observed in oxyphil cells of parathyroid glands, in striated duct cells of parotid glands, in urinary tubules of kidneys, in parietal cells of gastric body mucosa, in oxyphil cells of Hashimoto's thyroiditis, in epithelial cells of Warthin's tumors of the parotid gland, in neoplastic cells of oxyphil adenomas and carcinomas (Hürthle's tumors) of the thyroid gland, and in neoplastic cells of oncocytomas of the kidneys. The present study shows that the epitope H is strongly expressed in mitochondria-rich normal cells, as well as in metaplastic and neoplastic oncocytic cells, which are known to have cytoplasms packed with mitochondria. Since mAbH recognizes an O-GlcNAc residue, our findings indicate that O-GlcNAc-glycosylated polypeptides are present at mitochondria where the components of the respiratory chain and energy transduction are localized. These findings may be of interest for gaining insight into the histophysiology of mitochondria-rich normal cells and into the pathogenesis of oncocytic lesions, since O-GlcNAc glycosylation may modify proteins involved in oncogenesis such as tumor suppressor proteins and oncoproteins, as well as proteins with important biological functions such as cytoskeletal proteins, transcription factors, heat-shock proteins, and chromatin proteins.

Altered gap and tight junctions in human thyroid oncocytic tumors: a study of 8 cases by freeze-fracture

Human oncocytic tumors of the thyroid gland may be either adenomas or carcinomas. The morphology and the ultrastructure of these oncocytes are well-known. Numerous studies have demonstrated the role of gap and tight junctions in experimental and human carcinogenesis; however, the junctional complexes of the oncocytic tumors have never been studied. The aim of this study is to analyze gap and tight junctions in the oncocytic tumors of the thyroid. Because they are morphologically similar, whether benign or malignant, they offer an attractive model for studying the junctional complexes in both benign and malignant lesions. Eight oncocytic human thyroid tumors were collected and studied by freeze-fracture. Four of these cases were benign and four were malignant. Four cases of normal gland were also studied to represent the control group. Normal tight and gap junctions were described for the control group. No gap junctions could be found for the oncocytic tumors. Furthermore, alterations of the tight junctions were described; especially focal tights in the oncocytic adenomas and well organized and labyrinthic tight junctions in the oncocytic carcinomas. The lack of gap junction in the benign as well as in the malignant oncocytomas may suggest that the absence of gap junction is not sufficient for malignancy. The alterations of the tight junctions found in the oncocytic tumors of the thyroid are similar to those observed in poorly differentiated tissues or tumors, and may suggest a cellular regression rather than a tumorogenic factor.

A histopathological and ultrastructural study of eccrine porocarcinoma with special reference to its subtypes

Five cases of eccrine porocarcinoma were studied by light and electron microscopy. Histopathologically, these could be classified into two types; the common and the giant cell type. The common type was characterized by almost uniform medium-sized cuboidal tumour cells and a formation of well-developed intracytoplasmic lumina. A broad diversity of histopathological and ultrastructural features was seen in these tumours. The tumours of the giant cell type consisted of mononuclear polygonal cells and bizarre giant cells. This type was considered to be an undifferentiated form of porocarcinoma.

Oncocytic neoplasms of the thyroid gland

Among well differentiated thyroid tumors, oncocytic neoplasms feature a distinctive set of clinical, morphologic and biologic characteristics, some of which have been a matter of controversy. The world literature on this subject has been reviewed to show that: 1) Morphology accurately predicts the behavior of Hürthle cell tumors assuming that the specimen has been adequately sampled; 2) Capsular and/or vascular invasion is the sine qua non condition for a diagnosis of malignancy; 3) "Indeterminate" or "possibly malignant" categories are useless because in the absence of invasion these neoplasms almost invariably behave in a benign fashion; 4) Among cases histologically classified as malignant, a clinically aggressive behavior is to be expected in a high percentage of cases; 5) Size alone cannot be used as a criterion of malignancy; 6) Less than total thyroidectomy provides an adequate treatment for histologically benign tumors; aggressive surgical procedures (i.e. total thyroidectomy) do not diminish the incidence of metastasis; 7) Analysis of DNA content may be helpful in defining subsets of patients with Hürthle cell carcinomas having a particularly poor prognosis; 8) Mitochondrial and/or nuclear DNA abnormalities probably play an important role in the cellular alterations which characterize the phenotype of oncocytes.

Oxyphil cells in thyroid disease: a uniform change?

Neoplastic and non-neoplastic oxyphil cells in thyroid disorders were investigated for enzyme and synthetic activity, ultrastructural features, and immune complex deposition. A reduced but definite content of thyroglobuliin and similar enzyme profiles and ultrastructural features in all types of oxyphill change were found. Immune complex deposition was seen in Graves' disease and Hashimoto's thyroiditis but not in oxyphil neoplasms or colloid goitre with focal oxyphil change. The findings suggest that oxyphil cells do represent a uniform change. Immunological damage with immune complex deposition might be the cause of oxyphil change in only some conditions.

Hürthle cell and mitochondrion-rich cell tumors. A clinicopathologic study

Hürthle cells are large eosinophilic thyroid cells that contain a large number of mitochondria with a high content of oxidative enzymes. In the last 10 years several reports have emphasized the disagreement over the morphologic features, biologic behavior and treatment of Hürthle cell tumors. The authors reviewed the clinical and pathologic features of 28 patients with Hürthle cell and mitochondrion-rich cell tumors (16 adenomas, 10 follicular carcinomas, and 2 papillary carcinomas) and present electron microscopic, immunohistochemical, and morphometric data. The results suggest that there is a correlation between biologic behavior and pathologic findings, that tumor size should not be considered a special conditioning factor in order to assign a biologic behavior, that nuclear size and anisokaryosis are not an absolute criteria for diagnosing malignancy, and finally, that electron microscopic examination is not useful in separating benign from malignant Hürthle cell tumors.

Canine laryngeal rhabdomyoma

Three canine laryngeal tumors were diagnosed as oncocytomas by light microscopy, but were determined to be rhabdomyomas following ultrastructural and immunocytochemical examination. Tumors consisted of large eosinophilic cells interspersed with smaller dark cells. Large tumor cells had a granular, intensely eosinophilic cytoplasm. Scattered through the tumors were a few elongated cells with cytoplasmic cross striations and multiple nuclei. Tumor cells from all three dogs contained numerous mitochondria and bundles of myofibrils with electron-dense Z-lines typical of striated muscle cells. Intracellular myoglobin and desmin were detected in the tumors by immunocytochemistry. Comparisons are made with a previous report of canine laryngeal oncocytomas.

Biochemical and immunohistochemical characterization of proteins in Hürthle cell carcinoma

The present study reports the biochemical and immunohistochemical findings in the cytosol of a Hürthle cell carcinoma as compared with that of normal thyroid tissue. Sephadex G-200 chromatography of the extract derived from a Hürthle cell carcinoma and from normal thyroid tissue revealed three identical pools. Pool I consisted mainly of thyroglobulin (Tg), pool II corresponded to albumin, while pool III contained unidentified low molecular weight fragments which could not be studied further. Hürthle cell carcinoma, pool I, had a Tg content of 12.9 micrograms Tg/mg equivalent tissue and a 127I content of 5,6 mole/mole of Tg. Its sialic acid content was undetectable, however. In pool I of the normal thyroid gland, the respective values were 62.8 micrograms Tg/mg equivalent tissue, 21.3 +/mole 127I/mole Tg, and 15.4 mole sialic acid/mole Tg. The albumin contained in both pools II was shown to be ioidinated at the following levels: 0.025 mole 127I/mole albumin in Hürthle tumor pool II vs 1.28 mole 127I/mole albumin in normal thyroid pool II. Immunohistochemical studies confirmed the presence of Tg and albumin in the malignant Hürthle cells and acini and colloid. Thus, Hürthle cell carcinoma contained Tg and albumin. The Tg content was five times less compared with control tissue. Both proteins (Tg and albumin) were poorly iodinated in Hürthle carcinoma tissue, and the iodination of albumina seemed to be more severely impaired. The site of synthesis of both proteins could not be derived from the present studies.

Oncocytoma of the ovary: light and electron microscopic study

An oncocytoma of the right ovary in a 22-year-old Japanese woman was examined by light and electron microscopy. The tumor was composed of oxyphilic cells with a granular cytoplasm. Electron microscopic studies revealed mitochondrial hyperplasia, a characteristic feature of the oncocyte . This may be the first report of an oncocytoma in the ovary.

Ultrastructural findings in Hashimoto's thyroiditis and focal lymphocytic thyroiditis with reference to giant cell formation

Ultrastructural findings in two cases of Hashimoto's disease and two cases of focal lymphocytic thyroiditis are reported. Stimulated thyrocytes, oncocytes and degenerating thyrocytes were observed in all cases. Multinucleated thyrocytes and epithelial pseudogiant cells were identified in Hashimoto's disease only. Infiltrating lymphocytes, plasma cells, monocytes and macrophages were present in all cases. The ultrastructure of germinal centres was similar to that seen in lymphatic organs. Giant cells of both intra- and extrafollicular localization were seen in Hashimoto's disease. Most of the giant cells were macrophage-derived. Two different ways of giant cell formation were identified: besides the familiar dissolution of plasma membranes of adjacent macrophages, another mechanism of fusion was observed. At sites of contact, peculiar membrane structures were developed and disintegration of plasma membranes occurred in parts adjacent to these structures. These are not identical to desmosomes and are different from Langerhans' granules. They probably represent special organelles for the initiation of cellular fusion.

Electron microscopic study on mitochondria in Hürthle cell adenoma of thyroid

In this investigation Hürthle cell adenoma of the thyroid was observed by electron microscopy. The cytoplasm of the cells consisted chiefly of an accumulation of numerous irregularly shaped mitochondria. Very few other organellae were observed. In addition electron microscopy revealed various degrees of electron density in the matrix of the mitochondria. When 3 dimensional models of the mitochondria were constructed, they revealed the mitochondria to have 3 dimentional forms which sometimes looked as if they might be dividing into two or three parts. The authors felt that this indicated a process of vigorous division of mitochondria and an extension of their life span. However, it was not possible to identify the cause of this division of mitochondria.

Electron microscopic investigations about the differentiation of thyroid carcinoma

36 thyroid carcinomas have been studied by means of electron microscopy. The specimens of 12 non-malignant thyroid lesions served as control. All the investigated tumours are composed of mixed populations of tumour cells differentiated in manifold variations. Differentiated carcinomas (follicular, papillary) often show misdifferentiations of the cytoplasm in light microscope, as well as in electron microscope. These misdifferentiations are the hyperplasia of a single cytoplasmatic organella or the hyperplasia of a system of organellas. The hyperplasia can be combined with a normal appearance of the respective organellas or with pathological changes of their morphology. Undifferentiated tumours often show structural remnants of folliculoid differentiation.

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.

Ultrastructural observations on the capillaries of human thyroid tumours

Ultrastructure of the capillaries of malignant and benign thyroid tumours has been examined. The material consisted of biopsies from six cases of thyroid papillary carcinoma, one case of follicular (foetal type) adenoma and six cases of nodular adenomatous goitre. In the group of nodular adenomatous goitre and in the follicular adenoma, the capillary wall was made up of fenestrated endothelium similar to that of capillaries of normal human thyroid. The fenestrae occupied a large area of the endothelial wall. Micro- and macropinocytotic vesicles were frequent in the endothelial cytoplasm. In the thyroid carcinomas the papillary structures always contained numerous capillaries with fenestrated endothelium. The microfollicular area and the solid tumoral areas of the papillary carcinoma showed occasional capillaries with fenestrated endothelium, but many capillaries were lined with continuous endothelium. The capillaries in all the specimens were surrounded externally by a continuous basement membrane which was frequently bilaminate or multilaminate. This study indicates that capillaries with fenestrated endothelium are characteristic of thyroid tumours which arise from follicular cells.

Triiodothyronine-secreting (toxic) adenoma of the thyroid gland: light and electron microscopic characteristics

A patient with thyrotoxicosis due to a triiodothyronine (T3)-secreting autonomous adenoma is described. The histmorphology of the neoplasms was similar to other neoplasms previously reported. Ultrastructural features of the adenoma are compatible with a very actively secreting follicular cell and are best compared with the ultrastructure of a diffuse toxic goiter. Distinctive features that separate toxic adenomas from various thyroid carcinomas and normal thyroid parenchyma are discussed.

Ultrastructure of the giant cell in de Quervain's subacute thyroiditis

The author made an electron microscopic observation on multinucleated giant cells which appear in the thyroid gland in subacute thyroiditis (de Quervain). Numerous typical desmosomes, which intermingled with myriad of mitochondria and small electron dense granules, were found in the cytoplasm of giant cell. Desmosome is one peculiar to the intercellular junction of follicular epithelium of the thyroid gland, and the fact that many desmosomes were found in the cytoplasm is one of the proofs showing this giant cell to be possibly derived from the follicular epithelium.

Transmission and scanning electron microscopy of experimentally induced thyroid tumors in rats

Irradiation of the neck region of 10 days old Wistar rats with 300 rads X-rays and their subsequent treatment with MTU leads to the development of thyroid tumors. The ultrastructure of the thyroid tumors induced was studied by transmission (TEM) and scanning electron microscopy (SEM). In follicular carcinomas, cylindrical or high columnar cells with abundant microvilli, well-developed ergastoplasmic reticulum and a hypertrophied Golgi complex predominate. The cytoplasm of the tumor cells of papillary carcinomas was composed of large pleomorphic cisternae, irregular in shape mitochondria, dense bodies, phagolysosomes and lamellar or multivesicular structures. Scanning electron microscopy revealed in the control animals a regular pattern of thyroid follicles tied to each other by tissue bridges and covered by set of blood and lymph vessels. The relief of the follicular carcinomas was irregular indicating follicles different in size and shape. The internal surface of the neoplastic follicles was also irregular as result of deep invaginations and intrafollicular cell growth. The apical region of the normal and neoplastic thyroid follicular cells was covered with abundant microvilli protruding into the colloid.

[Comparative light and electron microscopic studies of oncocytic pituitary adenomas (author's transl)]

In a collection of 108 surgically removed, light and electron microscopically studied pituitary tumors, 19 adenomas (17.6%) could be found of which oncocytic tumor cells constituted more than 50%. These showed histologically, in conformity with the criteria of oncocytes, a fairly broad cytoplasm with finely granular or, in part, finely vacuolar structures and distinct cell membranes. The nuclei were predominantly round and moderately rich in chromatin but also in part, pyknotic. In paraffin-embedded sections the tumors could not be distinguished with certainty from chromophobe or moderately granulated acidophil adenomas. In plastic-embedded sections they could be identified by the typical filmy and finely granular feature of the cytoplasm which was distinctly different from conglomerations of secretory granules. Ultrastructurally they were characterized by many densely packed mitochondria. These were, in part, hydropically swollen. Furthermore, 5 tumors exhibited increased hormone-synthesizing organelles, 2 of which induced an acromegaly. Probably the oncocytic pituitary adenomas are secondarily transformed chromophobe or moderately chromophil tumors which must be regarded as independent, for the most part endocrinologically inactive pituitary tumors. In addition to these purely or almost purely oncocytic tumors further 12 adenomas (11.1%) with oncocytic parts constituting between 10 and 50% of the tissue were in our collection. Of these, 5 were moderately or distinctly acidophil adenomas with clinical symptoms of acromegaly; 2 were, for the most part, mucoid cell adenomas with Nelson's syndrome.

Mitochondriosis of the hepatocytic cytoplasm in rachitic rat liver after calcitonin-treatment (a cytophotometric and morphometric study)

A calcium-rich rachitogenic vitamin-D deficiency and additional doses of calcitonin cause serious changes in cell structure and metabolism, which can be demonstrated by cytophotometry and morphometry. The experiments were made with 9 male juvenile Wistar rats. 6 animals were kept on a vitamin-D deficient diet for 6 weeks and 3 of these animals got injections with salmon-calcitonin S.C. during the last 14 days every second day. The remaining 3 animals, fed with altromin-R standard diet were kept for control purposes only. The morphometric analysis of the liver parenchymal cells was based on the statements by Weibel and the cytophotometric examinations were made according to the Sandritter technique. As a consequence of the altered metabolic condition a great volume reduction of cells and cell nuclei is found in the animals with vitamin-D deficiency, which were treated with calcitonin. In comparison with the control animals the hepatocytes show hardly any tetraploid nuclei, which points to an inhibited polyploidization. The cytoplasm shows an oncocytic transformation with megamitochondria. As reason for this mitochondriopathy an extreme and abnormal growth as well as a mutation of the mitochondrial genom are under discussion. Furthermore the total endoplasmic reticulum (volume and membrane surface), the peroxisomes and the ribosomes are strongly reduced. Due to the serious cell injury the other organelles are also reduced in number and volume, which points to a chronic hypocalcemia.