Aspiration cytology of neuroblastoma: light microscopy with transmission and scanning electron microscopic correlations

Fine-needle aspiration biopsies from three patients with neuroblastoma were studied by light microscopy, and the morphologic findings were correlated with those from transmission and scanning electron microscopy. Light microscopic examination of the aspiration smears from all three cases revealed small and large round cells with variable numbers of intertwining cytoplasmic processes. Transmission electron microscopy confirmed the light microscopic finding of cytoplasmic processes; in addition, it revealed the presence of other diagnostic morphologic features, including neurosecretory granules, microtubules, and synaptic cell junctions. Scanning electron microscopy demonstrated that the tumors were composed of a mixture of undifferentiated round cells and more differentiated cells with long cytoplasmic processes. The morphologic spectrum of these processes and their interrelationships with one another and with other cells could be studied in detail. These findings indicate that scanning electron microscopy may be used effectively in the morphologic evaluation and pathologic diagnosis of neuroblastoma.     

Scanning electron microscopic study of capillary change in bleomycin-induced pulmonary fibrosis.

The architectural changes which occur in the capillaries are difficult to illustrate without a three-dimensional tool, such as scanning electron microscopy. Therefore, a scanning electron microscopic study was occasionally undertaken to show the capillary changes of lung fibrosis. Fibrosis was induced in twenty rats by an intratracheal injection of bleomycin. After 30 days the rats were sacrificed, and light microscopy and scanning electron microscopy were performed. The vascular trees of both lungs were cast with methacrylate. Light microscopically, the pulmonary fibrosis was patchy and inflammatory cell infiltration was rather sparse. Scanning electron microscopically, the intercapillary spaces became wider; and some capillaries revealed large irregular dilatation. The pleural and alveolar capillaries were variably dilated. The pleural capillary diameter was increased (P = 0.06), and the capillary plexus diameter was decreased (P = 0.00). Distance between the capillary branches of the pleural surface was increased (P = 0.06). The appearance of irregularly shaped capillaries, an increase in diameter with variable dilatation of alveolar capillary rings and a decrease in branching between the capillaries, resulting in a loss of surface area are the main scanning electron microscopic findings of the remodeling which occurs pulmonary capillaries in bleomycin-induced pulmonary fibrosis.     

Cardiovascular ochronosis

A 64-year-old man with alkaptonuric ochronosis required aortic valve replacement for severe aortic stenosis and single-vessel aortocoronary artery bypass grafting for a subtotally occluded obtuse marginal branch of the circumflex coronary artery. Operative findings included ochronosis of a partly calcified aortic valve and the aortic intima. The aortic valve and a punch biopsy specimen of the ascending aorta were removed at surgery and were studied with transmission electron microscopy and light microscopy. The ultrastructural studies of the aortic valve revealed intracellular and extracellular deposits of ochronotic pigment. A portion of the extracellular ochronotic pigment represented degenerated cells. Large deposits of extracellular ochronotic pigment were associated with areas of valvular calcification. Electron microscopic study of the aorta disclosed ochronotic pigment in macrophages and smooth-muscle cells. Aggregates of extracellular ochronotic pigment in the intima and media appeared to be in locations of necrotic cells. Light microscopy also showed intracellular and extracellular deposits of ochronotic pigment. Our study suggests that extensive extracellular deposits of ochronotic pigment in the aortic valve may serve as a stimulus for dystrophic calcification. This may play a role in the development of aortic valve calcification and aortic stenosis associated with alkaptonuric ochronosis. To our knowledge, this is the first ultrastructural study of the aortic valve and aorta in alkaptonuric ochronosis.     

Scanning electron microscopic observations of casts of human dentinal tubules along the interface between primary and secondary dentine

A scanning electron microscope cast technique was used to examine the interface between primary and secondary dentine in young and old human teeth. In addition, more traditional methods were used to examine this interface with light microscopy, identical regions being viewed before and after demineralization. No continuity was seen between the tubules in primary dentine and those in irregular secondary dentine in the scanning electron microscope preparations. These preparations did show the tubules to be continuous between primary dentine and regular secondary dentine in young and old teeth. Both the scanning electron microscopic and light microscopic observations suggested that regular secondary dentine becomes highly sclerosed in old teeth.     

An ultrastructural and light microscopic study of the synovium in ochronotic arthropathy

The synovium in two well-documented cases of alkaptonuric ochronosis was studied by transmission electron and light microscopy. A feature of alkaptonuria previously unreported in the English-language literature was the presence of phagocytosis of large collagen fibrils by synovial macrophages in both cases. The origin of these fibrils appeared to have been shards of ochronotic cartilage and areas of metaplastic cartilage. This finding suggests that active remodeling of the synovial tissues occurs in advanced ochronotic arthropathy. Numerous shards of ochronotic cartilage were embedded in the synovium. In addition, small aggregates of large collagen fibrils encrusted with apparent ochronotic pigment were occasionally noted in the interstitium. These aggregates of ochronotic collagen are best described as microshards, and they have not generally been recognized in the literature. What appeared by light microscopy to represent ochronotic pigment deposition in interstitial collagen actually represented embedded microshards of ochronotic cartilage in the interstitium. Slender and elongated microshards were most likely to be confused by light microscopy as ochronotic interstitial collagen.     

Occult lupus nephropathy: a correlated light, electron and immunofluorescent microscopic study

Renal biopsies obtained from four adolescent girls who developed symptomatic thrombocytopenia with serologic evidence of systemic lupus erythematosus, without clinical signs of renal involvement, showed glomerular disease by electron and immunofluorescent microscopy with light microscopic changes in two cases. Subsequently, three of the patients developed proteinuria, and repeat biopsies from all four showed appearances ranging from resolution to significant glomerulitis. The findings illustrate the variable patterns of occult glomerulitis in lupus, and highlight the value of correlating light, electron and immunofluorescent studies in renal pathology.     

Scanning and transmission electron microscopic observation of femoral head feeding vessels in stroke-prone spontaneously hypertensive rats

Stroke-prone spontaneously hypertensive rats (SHRSP) are known to show necrosis of the femoral head with a frequency of about 50%. This rat has thus been used as an animal model for necrosis of the femoral head in many studies. In a detailed investigation of feeding vessel disorders that cause femoral head necrosis, we observed changes over time in the feeding vessels using scanning electron microscopy and transmission electron microscopy. In scanning electron microscopy of vascular casts, abnormal findings in feeding vessels of SHRSP with aging from the immature stage included contortion and bending in the lumen with overall narrowing. Under transmission electron microscopy, decreased numbers of smooth muscle cells and increased amounts of collagen fibers were marked, and these changes with hypertrophy of vascular walls might be similar to those of arteriolosclerosis. The structural changes first revealed by transmission electron microscopic observation might cause the friability of the feeding vessels so that contortion and bending occurred, suggesting transient obstruction of blood flow to the femoral head and subsequent induction of femoral head necrosis. These findings should help in understanding the causes of femoral head necrosis in humans, including Perthes’ disease.     

Glomerular basement membrane discontinuities. Scanning electron microscopic study of acellular glomeruli.

Glomerulonephritides which develop necrotizing and crescentic lesions usually have glomerular basement membrane (GBM) disruptions when carefully examined by light microscopy or transmission electron microscopy. Despite numerous excellent and detailed ultrastructural investigations of GBM discontinuities, a complete appreciation of their actual number, appearance, and distribution within a glomerulus has been difficult to achieve by reconstruction of two-dimensional light or transmission electron microscopic images. Selective removal of podocytes by a sequence of lytic and solubilization procedures has been developed which exposes any structural alteration of the GBM to direct examination by scanning electron microscopy. A case of idiopathic, immune-complex-negative, focal-segmental necrotizing glomerulonephritis has been studied by this technique, permitting three-dimensional visualization of the GBM defects which result in free communication between the vascular and urinary spaces. These disruptions were distinctive by their frequency within an affected lobule, variable size, and sharply demarcated edges. Application of this technique to human renal biopsies is capable of enhancing our understanding of the morphologic alterations occurring in human glomerulonephritis.     

Intraventricular neuroblastoma. A light and electron microscopic study and review of the literature

The neuroblastoma can generally be diagnosed from the histologic findings, but electron microscopic evidence is often required. A neuroblastoma occurring in the lateral ventricle of a 17-year-old female is described in this report. The tumor cells, which were strongly stained with hematoxylin, contained a small round or oval nucleus with scant cytoplasm and an obscure cell border as observed by light microscopy. No calcification, mitoses and typical ganglion cells were detected. An electron microscopic examination disclosed dense-cored vesicles, cell processes, clear vesicles, dumbbell-shaped dense bodies, microtubules and zonulae adherentes in the tumor cells. These findings suggest differentiation of the tumor cells to neuronal cells.     

Parathyroid glands in primary hyperparathyroidism: an ultrastructural study of 50 cases

Parathyroid glands from 50 cases of primary hyperparathyroidism were examined by light and electron microscopy in an attempt to elucidate the diagnostic role of electron microscopy in this disease. In the cases in which only one gland was removed at surgery, a final diagnosis by light microscopy was not possible. The electron microscopic findings for some of these single glands (e.g., ribosomal-lamellar complexes and groups of centrioles) suggested that they were adenomas. In cases in which two or more enlarged glands were removed, a correct final diagnosis could be made on the basis of the light microscopic findings alone, and electron microscopy provided no further significant information. Where one enlarged gland and one normally sized gland were removed, electron microscopy disclosed important findings in the normally sized glands. Specifically, light microscopic examination of normally sized glands suggested endocrine suppression, while electron microscopy showed chief cell activity, thereby changing the final diagnosis from adenoma to hyperplasia. The clinical follow-up assessment in some of these patients confirmed the electron microscopic findings. Therefore, the incidence of adenoma in patients with primary hyperparathyroidism should be critically re-evaluated by ultrastructural studies of the normal glands that should be removed with the enlarged ones.     

Light microscopic findings on globular hyalin bodies in the human liver and its electron microscopic equivalents (author's transl)]

According to electron microscopic investigations, there is no uniform substratum and no uniform formal pathogenesis in the light microscopic appearance of globular hyalin bodies in the liver. This paper presents a survey on the different electron microscopic equivalents of the light microscopic findings of globular hyalin bodies in human liver biopsies. These electron microscopic equivalents, their occurrence, their different pathogenesis and, resulting from this, their different diagnostic and prognostic significance are described and demonstrated in detail.     

Scanning electron microscopic study of precancerous and cancerous pancreatic lesions induced by N-nitrosobis (2-oxopropyl) amine in Syrian golden hamsters

Sequential alteration of Syrian golden hamster pancreatic ducts and ductules was investigated by scanning electron microscope during and subsequent to 10 weekly subcutaneous injections of N-nitrosobis (2-oxopropyl) amine (BOP). By examining surface morphology of ductal cells and resin casts of the secretory branches arising from the common duct, a series of lesions ranging from slight derangement of the luminal dimensions and loss of cilia to marked projections of "finger-like" processes accompanied by pleomorphism at the cellular and microvilli levels and increase in numbers of goblet cells could be established. A ductal histogenesis is proposed on the basis of the present scanning electron microscopic and earlier light microscopic findings.     

Scanning electron microscopic surface topography of ablation catheter perforations and calcific tear in an explanted bioprosthetic heart valve

The authors report a triplet of leaflet destruction in a bioprosthetic aortic valve explanted at 12 years after iatrogenic ablation catheter perforation in a patient who underwent coronary artery bypass surgery and multiple ablative procedures in the interim. Lesions were examined topographically by scanning electron microscopy. Calcium content was evaluated by mass spectrometry and Von Kossa staining. Leaflets exhibited little calcification, except at the commissures of the valve. Scanning electron microscopy revealed distinct lesion topography. The authors present the scanning electron microscopic characteristics of these lesions and of an incision into the valve made for comparison using a pair of scissors. This is believed to be the first report of scanning electron micrographs of ablation catheter perforations and a calcific tear in the same explanted valve. The findings provide a source for comparison in the etiological determination of explanted bioprosthetic valve lesions using scanning electron microscopy.     

Comparative Light, Scanning, and Transmission Electron Microscopic Study of Chemically Induced Premalignant Lesions in Hamster' Cheek Pouch

The early chemically induced epithelial dysplastic changes in the hamster' cheek pouch were studied using light, scanning, and transmission electron microscopy. Epithelial dysplasia was noticed on the light microscopic level by the sixth week of the experiment and became marked by the eighth week. At the scanning electron microscopic level, surface alterations with features previously reported in early epithelial dysplasis in human and oral mucosa were seen by the second week of the experiment and progressed over time. These early changes were also confirmed at the ultrastructural level. The usefulness of scanning and transmission microscopy in detecting early oral epithelial dysplastic changes in this animal model is discussed.     

Electron microscopic study of nuclear and nucleolar changes in cells infected with canine distemper virus (CDV)

Summary The nuclear changes occurring in dog kidney cells infected with a virulent and an attenuated strain of canine distemper virus were examined by electron microscopy. No ultrastructural evidence for intranuclear virus replication was observed even though large eosinophilic nuclear inclusions were found in up to 34% of infected cells examined by light microscopy. This discrepancy between light and electron microscopic findings was discussed in relation to the possible structure of the nuclear inclusions. Marked morphological changes were noted in the nucleoli of up to 12% of cells infected with the virulent strain, CDV/BR, involving complete segregation of the granular and fibrillar components. The nucleolar lesions were similar to those induced by chemical inhibitors of cellular nucleic acid metabolism.     

Comparative Light,Scanning, and Transmission Electron Microscopic Study of Chemically Induced Premalignant Lesions in Hamster' Cheek Pouch

The early chemically induced epithelial dysplastic changes in the hamster' cheek pouch were studied using light, scanning, and transmission electron microscopy. Epithelial dysplasia was noticed on the light microscopic level by the sixth week of the experiment and became marked by the eighth week. At the scanning electron microscopic level, surface alterations with features previously reported in early epithelial dysplasis in human and oral mucosa were seen by the second week of the experiment and progressed over time. These early changes were also confirmed at the ultrastructural level. The usefulness of scanning and transmission microscopy in detecting early oral epithelial dysplastic changes in this animal model is discussed.     

Hairy cell leukemia. Electron microscopic observations of two cases

Electron microscopic studies were done on two cases of hairy cell leukemia. Although scanning electron microscopy did reveal typical features of hairy cells, in most abnormal cells, transmission electron microscopy clearly showed that there are two distinct types of cell populations. These two types of leukemic cells with respective lymphoid and non-lymphoid characteristics warrant further investigation.     

Electron microscopic study of pyelointerstitial reflux scars

In addition to confirming the established light microscopic findings, electron microscopic assessment of renal tissue with pyelointerstitial reflux damage also provides other important information. Isolated tubular epithelial cells and small tubular epithelial cell complexes, the earliest formative phase of thyroid-like lesions, were observed after subtotal tubular destruction. Moreover, secretory granule-like structures, identified by immunohistologic methods as renin granules, were found in tubular epithelium, apparently atrophic and cell-rich glomeruli, and walls of tortuous arterioles. Various stages of glomerular scarring were documented in the early phase of glomerular destruction and electron-dense material (IgM) was identified. Electron microscopy plays an important role in differentiating thin-walled vessels (lymphatic vessels, capillaries, venules). While the presented findings are characteristic for reflux nephropathy, they are not pathognomonic: they also occur, for example, in urinary tract obstructions without reflux mechanism.     

Acute radiation nephritis. Light and electron microscopic observations.

Light and electron microscopy were used to observe acute radiation nephritis. By light microscopy the changes were of fibrinoid necrosis of the arteries and atrerioles with segmental necrosis of the glomerular tufts. By electron microscopy the endocapillary cells reacted by hypertrophy and hyperplasia with increase in cytoplasmic organelles. In addition, disruption of endothelial and epithelial cells from the basement membranes were seen. It is concluded that the electron microscopic changes were unique and may be helpful in differentiating the necrotizing glomerulitis seen in other conditions, especially malignant hypertension.