Histologic and ultracytochemical studies on thyroid medullary carcinoma. Diagnostic significance of argyrophil secretory granules

Ultrastructural and electron immunohistochemical features of medullary thyroid carcinoma

An ultrastructural study, both morphological and immunohistochemical, has been carried out on eight thyroglobulin-positive and nine thyroglobulin-negative medullary carcinomas of the thyroid. The morphometric analysis of granule size showed that all tumours contained cells with small granules and cells with medium size granules, whereas eight tumours had additional cells with large granules. The small granules had an electron dense core, while the medium and large sized granules were both pale-cored and dense-cored. The cells with small, medium or large secretory granules were all immunoreactive for calcitonin and CGRP. No ultrastructural differences were observed between thyroglobulin-positive and thyroglobulin-negative cases of medullary carcinoma of the thyroid.

Mixed medullary-follicular carcinoma of the thyroid. Immunohistochemical and electron microscopic studies

A case of mixed medullary-follicular carcinoma of the thyroid is reported. Grossly, the tumor was a solid, grayish-white, well circumscribed mass without lymph node metastasis. Microscopically, the tumor showed both medullary and follicular areas. The follicular areas occupied discrete portions of the tumor, and were considered to be neoplastic. Tumor cells in the medullary area were polyhedral or spindle-shaped. There was no amyloid deposition within the tumor. Immunohistochemically, tumor cells in the medullary area were positive for calcitonin and negative for thyroglobulin. Some cells lining the follicles were positive for thyroglobulin. By electron microscopy, two types of tumor cell were observed. One type contained numerous cytoplasmic secretory granules, whereas the other type had few granules and showed a prominent rough endoplasmic reticulum. These findings suggested that this mixed medullary-follicular carcinoma of the thyroid presented neoplastic changes within a common cell lineage.

Follicular and papillary variants of medullary carcinoma of the thyroid

Two medullary carcinomas of the thyroid (MCT) with relatively unusual patterns are reported. The first was an aggressive tumour which occurred in a 66-year-old man and displayed in most areas follicular structures. The second tumour occurred in a 36-year-old woman, followed a benign course and showed papillary infoldings lined by multilayered neoplastic cells. The search for thyroglobulin yielded negative results whereas calcitonin immunoreactivity could be found in most neoplastic cells of both tumours. The diagnosis of MCT was further substantiated by the presence of scarce amyloid deposits and typical neuro-secretory granules by electron microscopy. These cases demonstrate once more that follicular and papillary structures can be a prominent feature of some MCTs reinforcing therefore the major role of immunocytochemistry in the differential diagnosis of thyroid carcinomas. Papillary MCT seems to carry a good prognosis in contrast to follicular MCT if one takes into account the follow-up data of the present cases together with those of similar cases reported in the literature; the whole series is nevertheless too small to allow for definite conclusions on this matter.

Immunohistochemical study of solid cell nests of the thyroid gland found from an autopsy study

An immunohistochemical study was performed to identify the histogenesis of solid cell nests (SCN) found in 30 of 202 thyroids obtained at autopsy. Immunoperoxidase staining was used to detect the presence of calcitonin, thyroglobulin, thyroxin, low and high molecular weight keratins, and carcinoembryonic antigen (CEA). Results showed that cells forming solid nests had immunoreactivity for calcitonin, low molecular weight keratin, and CEA, but not for thyroglobulin, thyroxin and high molecular weight keratin. Thus, SCN do not result from tangentially cut thyroid follicles (absence of staining for thyroglobulin and thyroxin), nor from a squamous metaplastic process (absence of staining for high molecular weight keratin), but instead they are formed by C-cells because they showed calcitonin immunoreactivity, and neurosecretory granules.

Metastatic C-cell carcinoma: calcitonin and CEA production in monolayer culture

Mechanically dissociated cells from a surgically removed mediastinal C-cell carcinoma (MTC) were cultured over a period of 4 months. The cells of the monolayer culture consisted of clusters of small epithelial-like cells. Using semithin and ultrathin sections, two different types of cells could be characterized by shape of nucleus and by content and distribution of secretory granules. One type of cell showed a more irregularly shaped nucleus, the other contained a large oval nucleus, similar to the normal C-cell of the human thyroid. Calcitonin (CT) and carcinoembryonic antigen (CEA) were measured in supernatants in duplicate by radioimmunoassays. Radioimmuno-detectable CT levels in the supernatant of culture medium varied between 0.8 and 1.6 ng/ml and CEA levels between 5 and 27 ng/ml during a 2-month period. The present study proves that in monolayer-cultured cells of a MTC, metastases continue to produce radioimmuno-detectable CT and CEA. Whether the two different cell types in culture are relevant for carcinoma needs further investigation.

Glandular (tubular and follicular) variants of medullary carcinoma of the thyroid

The original descriptions of medullary carcinoma stressed the lack of papillary and follicular differentiation and the presence of amyloid. During the last few years, the spectrum of histological features seen in tumours of C cell origin has broadened, and papillary and anaplastic forms have been reported. We have recently studied three cases of medullary carcinoma with a major 'tubular' or 'follicular' component, giving a microscopic picture suggestive of follicular carcinoma of the thyroid. These cases were studied with routine techniques, electron microscopy, and immunohistological methods using antibodies to calcitonin and thyroglobulin. In all three cases the calcitonin localization was positive, and apart from included peripheral thyroid follicles, the thyroglobulin was negative--even in the tumour with large follicles containing PAS positive colloid. In the cases with tubular lumina, electron microscopy showed a concentration of granules in the apical portion of the cells, with corresponding immunolocalization of calcitonin in a ring about the lumen. We conclude that medullary carcinoma should be considered in the differential diagnosis of every unusual thyroid carcinoma, even those showing glandular differentiation and containing apparent follicles, and that immunolocalization techniques using calcitonin and thyroglobulin are essential for accurate diagnosis of thyroid carcinomas.

Primary pulmonary ganglioneuroblastoma in an adult: maturation, involution and the immune response

The features of a primary pulmonary ganglioneuroblastoma occurring in an adult are presented. The tumour showed evidence of both maturation and involution. Maturation appeared to be occurring in a centrifugal manner, a rim of mature ganglioneuromatous tissue enclosing the primitive neuroblastoma. Necrosis of the neuroblastomatous element was widespread and associated with deposition in the walls of numerous small vessels of an amorphous eosinophilic amyloid-like material. Accumulation of this material had led to occlusion of some vessels with resultant necrosis of related tumour. A collarette of lymphocytes surrounded the tumour, and lymphocytic aggregates were prominent at the interface between neuroblastoma and ganglioneuroma. Despite widespread vascular invasion, the patient remains well and apparently tumour-free, 2 1/2 years post-resection. The appearances may represent a combined cellular and humoral host response, and a possible relationship of this response to tumour maturation is suggested. The potential role of immunostimulation in the treatment of neuroblastoma is discussed.

Malignant carotid body paraganglioma: light and electron microscopic study of the tumor and its metastases

A right carotid body paraganglioma (CBP) was removed from a 30-year-old female after finding metastases to cervical lymph nodes. The tumor and its metastases were studied by light and electron microscopy to determine the neoplastic cell type. Light microscopy confirmed the presence of chief cells but was inadequate alone to exclude sustentacular cells. By electron microscopy, only chief cells were found in both the primary and secondary tumors. This is the first report of an ultrastructural study of a metastasis from a malignant CBP. From our observation, we suggest that CBP be defined as a proliferation of chief and sustentacular cells. Electron microscopy is essential to determine the cell types present and thereby help classify the lesion as a tumor or hyperplasia of the carotid body.

Strumal carcinoid of the ovary: an analysis of 50 cases of a distinctive tumor composed of thyroid tissue and carcinoid

Strumal carcinoid of the ovary is a type of germ-cell tumor characterized by an intimate mixture of thyroid tissue and carcinoid. Fifty patients with this type of tumor ranged in age from 21 to 77 years. The tumors measured up to 26 cm in diameter and were always unilateral. In 10% of the cases, the contralateral ovary contained another type of neoplasm, usually a dermoid cyst. Three-fifths of the strumal carcinoids arose in dermoid cysts or in mature solid teratomas. Birefringent calcium oxalate monohydrate crystals were commonly identified in the thyroid colloid, and argentaffin granules, in the carcinoid cells, thus substantiating the identity of the neoplastic components. Although 31% of the tumors were accompanied by focal stromal luteinization, only 8% of the cases exhibited clinical signs of steroid hormone production (endometrial hyperplasia, hirsutism, or virilism). In 8% of the cases, there was evidence suggesting functioning of the thyroid component, but no patient had the carcinoid syndrome. Only one woman died of tumour; five others died of unrelated causes. The remaining patients remained alive and well; 23, for at least five years, and 15, for at least ten years postoperatively. Although the carcinoid component of the strumal carcinoid has been considered a malignant transformation of struma ovarii, it is almost always benign, and treatment with a simple oophorectomy or salpingo-oophorectomy is effective.

Identification of carcinoembryonic antigen in the C-cell of the normal thyroid

Carcinoembryonic antigen (CEA) activity was confirmed in the C-cell of the normal thyroid by immunohistochemical techniques. This suggests that CEA production in medullary carcinoma of the thyroid is not initiated by carcinogenesis, but reflects a function of the normal C-cell. It is not yet clear whether CEA production in the C-cell may be influenced by carcinogenesis. The C-cell is the first APUD cell that was confirmed to have CEA activity.

Immunohistochemical study of the medullary thyroid carcinoma with reference to C-thyroglobulin reaction of tumor cells

Twelve cases of medullary thyroid carcinoma were investigated ty the immunoperoxidase method using anti-calcitonin, anti-C-thyroglobulin (C-Tg, C cell-immunoreactive thyroglobulin) and anti-19S thyroglobulin antisera. Tumor cells as well as normal C cells revealed distinct immunoreaction for C-Tg besides for calcitonin. In contrast to normal C cells, the tumor cells were stained more intensely by anti-Ctg antiserum than by anti-calcitonin antiserum. Furthermore, there occurred several tumors or some areas of tumors which showed strong response to anti-C-Tg antiserum but weak or no response to anti-calcitonin antiserum. Thus, medullary carcinoma cells synthesized far greater amounts of C-Tg than calcitonin. The small follicles were occasionally observed mingled in typical cell solid masses. They stored colloid-like materials which were intensely immunoreactive to C-Tg but nonreactive to calcitonin. The specific immunoreaction patterns to anti-C-Tg and anti-calcitonin antisera were also obtained on the ground materials of the amyloid. On the histogenesis of amyloids of medullary carcinoma, the C-Tg could be the presursor of the fibrillar protein of amyloids and the component of the fibrillar protein also closely related to calcitonin.

C cell carcinoma of the thyroid--papillary type

Two cases of papillary type of C cell carcinoma of the thyroid were reported. They showed papillary arrangement with fibrovascular stalk in properly fixed tissues. Histochemically argyrophil reaction was positive in the cytoplasm and amyloid deposited in the stroma. Ultrastructurally secretory granules were found in their cytoplasm. The papillary type is not an artifact but one of the histologic variations of this carcinoma.

Canine medullary carcinoma of the thyroid

An 8-year-old male Irish Terrior dog and a male St. Bernard dog each had a thyroid medullary carcinoma. The first dog was hypocalcemic before removal and with recurrence of the neoplasm. In both dogs the neoplasms were bilateral and microscopic metastases were seen only in the regional lymph nodes. Both neoplasms were characterized by a solid alveolar pattern separated by thin vascular stroma or a linear festoon-like arrangement with thick stroma. The neoplastic cells varied little and were polygonal or round with abundant pale eosinophilic and finely granular cytoplasm. There was little mitotic activity. Both carcinomas contained amyloid. Electron microscopically, the neoplastic cells had moderate nuclear pleomorphism, well developed Golgi complexes, and characteristic membrane-bound electron-dense secretory granules. In some sections, the secretory granule membranes were fused to the cytoplasmic membrane and the granules were in the extracellular space. In one carcinoma there were linear fibrillar structures with an average width of 7.8 nanometers similar to that of amyloid fibrils.

The fine structure of human thyroid cancer

This ultrastructural description of human thyroid cancers is based on the available literature and on our own studies of about 150 cases. Electron microscopy is an invaluable diagnostic adjunct to light microscopy, as it may eliminate inaccurate designations such as "small cell malignant tumors of the thyroid," which include tumors of different histogenetic origin with a different prognosis and treatment that share only a similarity in appearance under the light microscope. Ultrastructure is also of diagnostic importance in cases of medullary carcinoma that imitate papillary or follicular patterns or lack amyloid stroma. Its importance in separating follicular adenomas from carcinomas, however, has not been proven. In conjunction with other methods ultrastructural study might throw new light on the controversial classification of papillary and follicular carcinomas and improve our understanding of their different biologic behavior. Immunoelectron microscopy may help in solving the problem of amyloid pathogenesis in endocrine tumors and in charting the subcellular mechanisms involved in the production of multiple polypeptide hormones in a single tumor.

Medullary carcinoma of the human thyroid in monolayer culture: morphological and cytochemical correlations

Mechanically or enzymatically dissociated cells from three human medullary thyroid carcinomas (MTC) were grown in monolayer culture for periods up to seven months. Cultures of each tumor contained clusters of small epithelial-like cells which were readily identified by phase contrast microscopy. Immunocytochemical studies and electron microscopy showed that these cells contained abundant calcitonin and numerous secretory granules. Amine-storing mechanisms were also demonstrable in these cells by formaldehyde-induced fluorescence. Homogeneous cultures of epithelial-like cells showed no evidence of transitions into fibroblast-like cells. Addition of thyroxin to the tissue culture medium appeared to promote survival of epithelial-like cells in cultures of one tumor. The ability to morphologically recognize cultured cells with endocrine activity should facilitate establishment of human MTC lines for biochemical and physiological studies.

Ultrastructural study of thyroid medullary carcinoma

This study deals with 11 cases of thyroid medullary carcinoma of which 7 were familial cases including 3 cases of Sipple's syndrome and 4 cases of sporadic cases. There were also 2 cases of Cushing's syndrome. In addition to the previously described English literatures about human medullary carcinoma of the thyroid, the rod-shaped body with cristae and an abundant glycogen particles in the cytoplasm, nuclear inclusion bodies of cytoplasmic invagination and microvilli at the surface membrane of gland formation were found in our cases. The mean and mode diameters of secretory granules of all familial cases with only calcitonin secretion were larger than those of the sporadic cases with ectopic ACTH and beta-MSH in addition to calcitonin secretion. Ultrastructural study on non-cancerous follicles of grossly normal thyroid of two cases of early familial medullary carcinoma disclosed apparently increased C-cells which were not intrathyroidal metastases. It is supposed that the increased C-cells in the thyroid of the familial cases are multicentric C-cell hyperplasia.

Histologic characteristics of insulinomas and gastrinomas. Value of argyrophilia, metachromasia, immunohistology, and electron microscopy for the identification of gastrointestinal and pancreatic endocrine cells and their tumors

In a first step of our investigation the staining characteristics, especially the argyrophilia and metachromasia, of immunohistologically identified endocrine cells of the pancreatic islets and of the gastroduodenal mucosa were tested. These staining characteristics were then examined on insulinomas and gastrinomas. Contrary to normal B cells which generally react positively with aldehyde fuchsin and pseudoisocyanine but not argyrophilic with the Grimelius method, the neoplastic B cells give inconsistent results with conventional staining methods. Yet neoplastic B cells often show argyrophilic structures. Immunohistologically, most benign insulinomas are rich in insulin-containing cells, whereas in malignant types such cells are rare. The carcinomas, however, show a typical and distinct Grimelius argyrophilia. The tumor cells of gastrinomas are Grimelius argyrophilic and slightly metachromatic, as normal G cells, yet, contrary to A1 cells, they are only exceptionally stainable with the Hellerström method. Despite the great number of Grimelius positive tumor cells, generally only a few reacted with antigastrin serum. Nevertheless, the immunohistology is the most reliable method for the diagnosis of gastrinomas. Electron microscopic results are often difficult to interpret, since gastrinomas, as well as undifferentiated or malignant insulinomas, may predominantly contain atypical secretion granules.

Argyrophil cell carcinoma (apudoma) of the esophagus. A histopathologic entity

In a series of 79 cases of primary esophageal carcinoma resected at The Center for Adult Diseases, Osaka, there were six tumors with specific histopathologic features valid for the diagnosis of argyrophil cell carcinoma. Of the 6 tumors, 3 were studied electron microscopically and assay for ACTH content was performed on 4 tumors. Clinically, the ages of the 6 patients ranged from 56 to 71 years; two were women and four men. Four of the 6 patients died with widespread tumor recurrences within 9 months of operation. Microscopically, the 6 tumors were composed largely or almost entirely of small, spindle-shaped cells resembling those of oat cell carcinoma of the lung, and were characterized by the arrangement of tumor cells in solid sheets or anastomosing cords, the presence of argyrophil tumor cells, and the deposits of amyloid. Electron microscopically, the three tumors contained neurosecretory-type granules. Using bioassay or radioimmunoassay ACTH activity in the tumor tissues was detected in 3 out of the 4 tumors determined. From the light and electron microscopic characteristics and the assay evidence, it seems reasonable to conclude that the 6 tumors are endocrine polypeptide producing tumors (apudomas) that arise from argyrophil cells normally found among the basal cells of the esophageal mucosa, and that they represent a distinct histopathologic entity clearly distinguishable from other types of esophageal carcinomas.

Medullary carcinoma of the thyroid. Diagnostic problems

Light microscopy is usually considered sufficient for the diagnosis of medullary carcinoma of the thyroid (MCT). As stromal amyloid is not always present and the tumor may exhibit great variation in growth pattern, light microscopy alone, however, may lead to misinterpretations. Of 1670 thyroid carcinomas registered durging a 15-year period in Norway, 42 were originally interpreted as MCT. The slides were reviewed and the diagnosis maintained in 33 cases only. Twenty-four additional cases were found by reviewing histopathologic slides from neoplasms originally registered as other types of thyroid tumors. Of 57 cases of MCT, stromal amyloid was demonstrated in 43. Calcitonin measurements and electron microscopy, even on formalin-fixed material, were valuable aids in establishing the correct diagnosis, though none of these methods are unequivocal. Different aspects of the problems concerning the diagnosis of MCT are discussed through the detailed presentation of five patients.

Neural properties of cultured human endocrine tumor cells of proposed neural crest origin

Cells from human endocrine tumors of proposed neural crest origin--five pheochromocytomas, two medullary carcinomas of the thyroid, and two bronchial carcinoids--were grown in monolayer culture. Cells from all nine tumors, including epithelial forms of medullary carcinoma of the thyroid and bronchial carcinoid cells, and epithelial and neuron-like pheochromocytoma cells demonstrated all-or-nothing, short-duration action potentials.

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.

The oxyphil and C cells of the human thyroid gland. A cytochemical and histopathologic review

The C and oxyphil cells of the human thyroid are analyzed in the light of recent advances in cellular biology, cytochemistry, and histopathology. The C cell is present in the normal human thyroid, where its identification is cardinally by means of argyrophilic cytoplasmic granules. The morphology, topography and argyrophilia of C cells are discussed with reference to tumor, cyst, and teratoma formation in the thyroid gland. Oxyphil cells of the thyroid are cytochemically akin to C cells but arise from follicular cells. They occur in the thyroid and other protein-producing organs, but are themselves inefficient producers of proteins and glycoproteins. Speculation is made on their morphological characteristics, and consideration is given to DNA-RNA involvement in the functional and morphological alterations of this follicular cell type.

Argyrophil cell carcinomas (apudomas) of the uterine cervix. Light and electron microscopic observations of 5 cases

Of a series of 97 invasive carcinomas of the cervix, 5 were found to have argyrophil tumor cells, and 3 of these 5 tumors were studied by electron microscopy. The ages of the 5 patients ranged from 36 to 49 years, with a mean age of 42.4 years. The morphologic features of these five tumors were well consistent with those described on a variety of endocrine polypeptide neoplasms such as thyroid medullary carcinomas, carcinoids, pancreatic islet-cell tumors, and oat cell carcinomas of the lung. Microscopically, the 5 tumors were characterized by the formation of solid-sheets, ribbons, streams, and rosettes. They were characterized electron microscopically by the presence of neurosecretory-type granules, the abundance of intracytoplasmic microfilaments, the absence of tonofibrils, and the paucity of desmosomal attachments. On the basis of the microscopic, electron microscopic and cytochemical characteristics, it is suggested that the tumors are a specific type of cervical carcinoma derived from the argyrophil cells, normally found among the linings of the endocervical glands and the cervical squamous epithelium. We believe these 5 tumors should be regarded as an endocrine tumor, another member of apudomas.

Diagnosis of medullary carcinoma of the thyroid by fine needle aspiration biopsy

Fine needle aspiration biopsy has been evaluated as a diagnostic method for medullary carcinoma of the thyroid (MCT) in 18 patients with verified hereditary or sporadic MCT. The typical MCT cell was asymmetrical, sometimes triangular and often with a characteristic red granulation in May-Grünwald-Giemsa staining. Eccentrically positioned, multiple nuclei were common. Amyloid was seen both intra- and extracellularly, staining blue-grey or violet with May-Grünwald-Giemsa and with green birefringence in polarized light after staining with alkaline Congo. The method was simple and quick to perform, causing negligible discomfort to the patient. No complications were seen. An adequate bioptic yield was obtained in 15 patients. In 13 of them (87 percent), including one patient with a normal thyroid at clinical examination, a correct diagnosis was reached.