Orbital metastasis from a carcinoid tumor. Computed tomography, magnetic resonance imaging, and electron microscopic findings.

An otherwise asymptomatic 63-year-old woman with a history of a carcinoid tumor of the ileum and a cutaneous melanoma of the shoulder developed unilateral proptosis. Orbital ultrasonography, computed tomography, and magnetic resonance imaging revealed a large, well-circumscribed orbital mass involving the superior rectus muscle. The surgically excised tumor was studied by light microscopy, histochemistry, and transmission electron microscopy. These studies confirmed the diagnosis of carcinoid tumor. The clinical and pathologic features of this rare type of orbital metastasis are discussed.

Morphological-histochemical study of intestinal carcinoids and K-ras mutation analysis in appendiceal carcinoids.

Intestinal carcinoids are potentially malignant neoplasms. Their histogenesis and pathogenesis are currently uncertain. The morphological and histochemical characteristics of twenty intestinal carcinoids are studied. The primary sites of three mucin-producing tumors were examined by electron microscope. Furthermore 11 appendiceal carcinoids were analysed by the polymerase chain reaction (PCR) for the detection of ras and p53 point mutations. Microscopically all carcinoids were of mixed type. Focal mucin production was evident in three carcinoids that metastasised to regional lymph nodes. HID-Alcian blue staining proved that mucin in both primary and secondary foci did not belong to the sulphated group. The secretory granules and mucin droplets found in a single neoplastic cell suggest that carcinoids of the small intestine and some of the appendix arise from the endoderm. Neither ras nor p53 mutations were detected. It seems that ras oncogenes are probably not involved in the pathogenesis of appendiceal carcinoids.

Gastrointestinal autonomic nerve (GAN) tumor. Ultrastructural evidence for a newly recognized entity.

We describe three cases of spindle cell tumors arising in the gastrointestinal tract, each with ultrastructural features that recapitulate the ultrastructural morphology of the enteric autonomic nervous system. These features include the presence of small, dense core granules in the synthetic-secretory Golgi structures, sparsely distributed within the ample tumor-cell cytoplasm, near plasma-membrane surfaces and within axons. Tumor cells had elongated processes and axons contained small granular vesicles, clear vesicles, or large, dense vesicles. Specific features diagnostic for smooth-muscle cell, Schwann cell, or fibroblast cellular origin were absent.

Multiple ileal carcinoids and appendiceal endocrine carcinoma in association with Meckel's diverticulum. A histochemical and immunohistochemical study.

An unusual case of multicentric ileal carcinoids and appendiceal endocrine carcinoma in association with Meckel's diverticulum was studied, with special attention given to the histogenesis of these neoplasms. A total of six ileal carcinoids, the largest of which was located in the wall of Meckel's diverticulum, were macroscopically and microscopically confirmed to be multicentric and revealed no visceral metastases. The histochemical and immunohistochemical profiles of the ileal carcinoids and the appendiceal carcinoma differed considerably: the former resembled subepithelial neuroendocrine cells and the latter resembled epithelial nonmucous cells and Paneth cells. The appendiceal carcinoma exhibited signs of endocrine differentiation, expressing somatostatin and vasoactive intestinal polypeptide, and secreted mucus. The tumor had metastasized to various organs. The carcinoids exhibited signs of neuroendocrine and glandular differentiation, expressing neuron-specific enolase, serotonin, chromogranin A, and endocrine granule constituent, and secreted little mucus. The data suggest different tumor cell origins or different grades of differentiation of the two types of intestinal endocrine cell tumor.

Carcinoids of the small intestine: a statistical evaluation of 1102 cases collected from the literature.

A total of 1102 cases of jejunoileal carcinoids collected from 516 articles reported by over 35 countries or related areas were evaluated. Among these 1102 cases. 93 cases of Meckel's diverticular and 969 cases of remaining jejunoileal carcinoids could be effectively analyzed. Multiple clinicopathologic aspects were investigated including clinical manifestations, location, depth and size of the lesions related to metastases, immunohistochemistry, electron microscopy, carcinoid syndrome and serotonin activity. Jejunoileal carcinoids were characterized by a male preponderance with an age group older than that in the extraappendiceal gastrointestinal (GI) series. They also had a significantly aggressive malignant nature exhibiting a high metastasis rate particularly evident in small-size lesions with submucosal invasion. A high incidence of argentaffin cell type and carcinoid syndrome with high serotonin activity was also exhibited by jejunoileal carcinoids.

Application of Grimelius argyrophil staining to the study of tumour ultrastructure. II. Effects of resin embedding: Epon.

2 methods have so far been proposed for staining samples by the argyrophil technique of Grimelius for electron microscopy. Vassallo et al. (1971) used en bloc staining after fixation with a mixture of glutaraldehyde and formaldehyde, then Håkanson et al. (1971) stained sections from samples previously fixed by double formaldehyde/OsO4 treatment and embedding in resin. Another investigation that concerned glutaraldehyde fixation showed the effect of this fixative in sample staining (Soranzo and Roland 1987). The present experiments demonstrated that Epon intervenes directly in argyrophil staining of sections. With this resin, the staining process lasted longer than with paraffin embedding materials and offered no guarantee of positivity. Granules with a double structure and dense core displayed different locality of argyrophilia before and after embedding.

Electron microscopy of intestinal adenomatosis in the blue fox, Alopex lagopus.

Scanning electron microscopy of adenomatous intestinal tissue in the blue fox revealed an irregular surface topography of the colon with increased diameter of the crypt openings and prominent ridge formations between crypts. The ileum showed villous atrophy and fusion. Microvilli were short and irregular. Small ulcerations of intestinal mucosa were seen. Freeze-fracture revealed curved intracellular organisms in the altered epithelial cells. Transmission electron microscopy showed features associated with immaturity and high protein synthesis. Filamentous extensions from the basolateral plasma membrane of altered epithelial cells sometimes penetrated the basal lamina. The cytoplasm contained numerous polyribosomes, nuclei had many indentations and large and irregular nucleoli. Intracellular bacteria, with morphology corresponding to Campylobacter spp. were found in the apical epithelial cytoplasm. No host-cell-derived membrane was seen to surround the bacteria.

Canine extracutaneous mast-cell tumours consisting of connective tissue mast cells.

Two cases of canine extracutaneous mast-cell tumours were encountered, originating from the mucosa of either the oral cavity or the small intestine. The dogs had no neoplasms in the skin. Immunohistochemical and ultrastructural studies demonstrated that the neoplastic cells had the features of connective tissue mast cells. It would seem, therefore, that at least some extracutaneous forms of the neoplasm originate from connective tissue mast cells. Heparin was a useful cytological marker to diagnose this type of mast-cell tumour.

[The differentiation of tumor cells of the human large intestine during the acquisition of multiple drug resistance]. / Differentsirovka kletok opukholei tolstoi kishki cheloveka pri priobretenii mnozhestvennoi lekarstvennoi ustoichivosti.

By selection in the medium containing increasing actinomycin D concentrations two sublines with acquired multidrug resistance (MDR) caused by P-glycoprotein (P170) overproduction were isolated. The obtained cell lines as well as parent cells grow in vitro as morphologically organized aggregates, so-called organoids. Comparative electron microscopic study of sensitive and drug resistant organoids has shown that the development of MDR was accompanied by the enhancement of the tumour cell differentiation: the percentage of differentiated cells, the extent of their maturity, and the quantity of lumens were higher in MDR organoids than in parent cell line. The size of glandular structures in resistant organoids was also enlarged. Possible mechanisms of observed phenomenon are discussed.

Malignant fibrous histiocytoma of the ileum.

Malignant fibrous histiocytoma occurs most commonly in the extremities and trunk, but rarely in visceral organs. This report documents a case of malignant fibrous histiocytoma arising in the terminal ileum. Following surgical resection, there is no evidence of recurrence or metastasis in this patient after one-year follow-up studies.

Dual carcinoid tumors of Meckel's diverticulum presenting as metastasis in an inguinal hernia sac: case report with literature review.

Neoplasms arising in Meckel's diverticulum or involving hernia sacs are rare. The authors present a unique case of two asymptomatic carcinoid tumors arising in a Meckel's diverticulum, which were discovered because of microscopic metastasis in a grossly unremarkable inguinal hernia sac. This article describes the clinical and morphologic features of this unusual case, reviews the topic of neoplasms involving hernia sacs and Meckel's diverticula, and includes a brief review of immunocytochemical findings in carcinoid tumors.

Tachykinin production by carcinoid tumours in culture.

Tissue specimens from 5 patients with metastatic midgut carcinoid tumours were kept in organ culture for up to 6 months. The tumour cells were confined to the suspension in the form of condensed cell clusters and appeared to retain their endocrine characteristics. Radioimmunoassay for tachykinin immunoreactivity showed high concentrations in 4 out of 5 culture media. The concentrations were highest in the beginning of the experiment, but subsequently decreased. The 4 patients from which these tumours were taken had all elevated tachykinin concentrations in extracted plasma. The fifth culture medium had low tachykinin concentration, and the concentration in extracted plasma from this patient was within the normal range. Reversed-phase high-performance liquid chromatography of the culture media with elevated tachykinin concentrations revealed immunoreactive components with the characteristics of synthetic neuropeptide K, neurokinin A and eledoisin, components also found in plasma and tumour tissues of carcinoid patients. Our findings indicate that carcinoid tumour cells produce tachykinins. These peptides are biologically very active, resulting in flush and hypotension when infused intravenously into normals, and might contribute to the clinical symptoms of the carcinoid syndrome.

Inflammatory fibroid polyp of the small intestine: ultrastructural and immunohistochemical observations.

The ultrastructural and immunohistochemical features of a primary tumor of the ileum showing the classic histologic features of an inflammatory fibroid polyp (IFP) of the gastrointestinal tract are presented. Ultrastructurally the proliferating cells showed a combination of fibroblastic and histiocytic features, with abundant rough endoplasmic reticulum and active production of collagen in many of the cells and long, dendritic cytoplasmic projections with large cytoplasmic vacuoles containing remnants of phagocytosed cellular debris in others. Immunohistochemical studies showed strong cytoplasmic positivity in the proliferating cells with vimentin antibodies and scattered positivity with muramidase. Additional findings include the ultrastructural demonstration of oligocilia and occasional primitive intercellular junctions. The findings in this case suggest that IFP may represent a proliferation of primitive submucosal stromal cells exhibiting incomplete fibrohistiocytic differentiation.

Massive pulmonary deposition of rutile after titanium dioxide exposure: Light-microscopical and physico-analytical methods in pigment identification.

Autopsy findings in a 55-year old man known to have been occupationally heavily exposed to titanium dioxide dust showed extensive pulmonary deposition of white pigment. By energy dispersive X-ray analysis (EDAX) and electron and X-ray diffraction, the pigment was identified as rutile. By ordinary transmitted light microscopy, deposits of the white crystalline titanium-dioxide could not be distinguished from anthracotic pigment present in the lung sections. By transmitted polarized and incident light microscopy, the different nature of the two types of pigment was immediately evident. Absence of inflammatory and fibrotic changes in the lungs in our case lends support to the view that rutile is biochemically inert.

Heterotopic gastric mucosa of the small intestine in laboratory beagle dogs.

Out of the 365 young laboratory beagle dogs which were used in 17 toxicity bioassays, 15 cases (4.1%) were diagnosed as having congenital heterotopic gastric mucosa of the small intestine. Its incidence in the male dogs (12 cases out of 187) was higher than in the female dogs (3 cases out of 178). Grossly, the lesions were seen as an ulcerous focus of the small intestine, 25 cm to 88 cm proximal to the ileocecal valve. All of the lesions were quite similar histologically and electron microscopically to the normal gastric mucosa, which are composed of the surface mucous cells, chief cells, parietal cells, mucous neck cells and basal granulated cells of the stomach. And consequently, they were considered to be that of a congenital heterotopic tissue in the small intestine. The only morphological characteristic of these lesions different from the regular gastric mucosa was an association with the tubular structure seen in the basal region of these mucosal layers. These cells were considered to be of mucous-secreting cell origin because of secreting type III mucous evident from paradoxical concanavalin A or periodic acid Schiff stains. They seemed to be protecting the surrounding intestinal mucosa from gastric acid.

Electron microscopic study of adenocarcinoma of the small bowel associated with Crohn's disease.

"Crohn's Carcinoma" of a 34-year-old patient is presented in this paper. The fine structure of the tumour is discussed in detail, because there have been no previous reports of electron microscopic studies of this tumour. The adenocarcinoma cells were electron microscopically less differentiated than expected on the basis of light microscopic examinations. In the tumor cells, several round dense granules were observed. Similar granules were also described in the cells of intestinal type gastric and colon cancers, being considered a sign of pathologic mucus secretion. In a part of the tumour cells, intracisternal parallel tubular inclusions were seen like those described in malignant melanoma and osteosarcoma. In the dysplastic small-bowel mucosa adjacent to the tumour, the maturation disorder of the epithelial cells was similar to changes described in the precancerous states of the colon.

Gastrointestinal autonomic nerve tumor presenting as high-grade sarcoma. Case report and review of the literature.

Gastrointestinal autonomic nerve (GAN) tumors, also known as plexosarcomas, are a rare distinct subtype of the gastrointestinal stromal tumors. These tumors are usually histologically low-grade, epithelioid or spindle-cell neoplasms that can be distinguished from the other gastrointestinal stromal tumors on the basis of their unique ultrastructural features. A 66-year-old female presented with a histologically high-grade sarcoma of the small bowel. Ultrastructural studies showed features of a GAN tumor. The light microscopic and ultrastructural features are described. The tumor cells gave strong, diffuse staining for vimentin and synaptophysin, and weak focal staining for neuron-specific enolase and S100. While usually presenting as low-grade neoplasms on histologic examination, this case demonstrates that GAN tumors should be considered in the differential diagnosis of a histologically high-grade sarcoma of the gastrointestinal tract, especially when evidence of smooth muscle, peripheral nerve sheath, or neuroblastic origin is not forthcoming.