Effects of Formaldehyde on the Nasal Mucosa

To investigate health effects of long-term exposure to formaldehyde a cross-sectional field study was performed. Seventy formaldehyde-exposed workers were compared with a control group. A higher frequency of symptoms from upper and lower airways, headache, and dermal discomfort was found in the formaldehyde-exposed group. Further, formaldehyde-exposed workers showed disturbances of nasal physiologic conditions, such as slow nasal clearance, impairment of the sense of smell, more pronounced nasal mucosal swelling, and by spirometry lower forced vital capacity than expected was found. Nasal biopsies from the concha media showed more frequent histologic changes such as loss of cilia and metaplasia in the formaldehyde-exposed group. Histologic lesions did not correlate to current or cumulative exposure doses to formaldehyde. In an experimental study of Sprague-Dawley rats exposed to formaldehyde (12.7 mg/m3, 6 hours/day, 5 days/week for 24 months), one rat developed a squamous cell carcinoma in the nose and another nasal dysplasia and in seven other rats pronounced nasal metaplasia was seen in the nasal mucosa. In a control group of rats no significant histologic lesions were found.

Role of ancillary techniques in profiling unclassified laryngeal malignancies

Laryngeal biopsies, contrary to biopsies from many other sites of the body, very often contain minute amounts of tumour tissue that may consist of morphologically undifferentiated tumour only. In haematoxylin- and eosin-stained sections, there may be no indicative features of what specific tumour entity that is present. In the larynx, particularly small round cell neoplasms, primary or metastatic, often cause a diagnostic dilemma and where an incorrect diagnosis can induce substantial clinical consequences for the patient (e.g., primary neuroendocrine carcinomas vs metastatic variants, certain sarcomas). If sufficient/representative material has been obtained, the application of immunohistochemistry and/or molecular techniques should in virtually every case reveal the true nature of the malignancy. In cases with sparse amount of material, and therefore a limited number of sections to be cut, a careful and thoughtful stepwise approach is necessary to ascertain a reliable diagnosis, or at least guide the clinician to the most likely diagnoses. With today's advanced and widely available technology with an abundance of markers to discriminate different tumours, the use of the term "undifferentiated" should be largely unnecessary. In the exceptional, and indeed exceedingly rare cases, when a classification is not possible, even after repeat biopsy, we suggest that the laryngeal neoplasm is better termed "unclassified malignant neoplasm" rather than "undifferentiated malignant neoplasm".

Salivary acinic cell carcinoma: reappraisal and update

Epidemiologic and clinicopathologic features, therapeutic strategies, and prognosis for acinic cell carcinoma of the major and minor salivary glands are critically reviewed. We explore histopathologic, histochemical, electron microscopic and immunohistochemical aspects and discuss histologic grading, histogenesis, animal models, and genetic events. In the context of possible diagnostic difficulties, the relationship to mammary analog secretory carcinoma is probed and a classification is suggested. Areas of controversy or uncertainty, which may benefit from further investigations, are also highlighted.

The Ljubljana classification: a practical strategy for the diagnosis of laryngeal precancerous lesions

There is no internationally accepted classification of epithelial hyperplastic laryngeal lesions (EHLL). The majority of current classifications follow criteria similar to those commonly used for cervical epithelial lesions. However, the different etiology of laryngeal cancer and its particular clinical and histologic features necessitate a grading system more appropriate to this region. The Ljubljana classification of EHLL was devised in 1971 to cater to this requirement. Detailed criteria for histologic grading in this classification were formulated by a working group on EHLL of the European Society of Pathology in 1999. The system recognizes four grades: simple and abnormal hyperplasia are benign categories; atypical hyperplasia ("risky" epithelium) is potentially malignant, and carcinoma in situ actually malignant. The main features by which the proposed grading system differs from other classifications are: 1. the distinction between benign and potentially malignant lesions; 2. the positive separation of carcinoma in situ from atypical hyperplasia; 3. the lack of prognostic significance for any surface keratin layer. The eventual outcome of EHLL patients so graded justifies the proposal for separating the lesions into a benign group, showing malignant transformation in only 0.9% of cases, from a potentially malignant group showing malignant transformation in 11% of cases. For diagnostically difficult cases, supplementary techniques such as those using morphometry, immunohistochemical and molecular biology are advised to improve the accuracy of diagnosis and predictions of their biological behavior.

Criteria for grading in the Ljubljana classification of epithelial hyperplastic laryngeal lesions. A study by members of the Working Group on Epithelial Hyperplastic Laryngeal Lesions of the European Society of Pathology

AIMS

To validate histological criteria for the grading of epithelial hyperplastic laryngeal lesions (EHHL) (dysplastic laryngeal lesions), we used a system that had been devised and tested in Ljubljana, Slovenia over many years and was felt to be more appropriate to laryngeal pathology than is the commonly-used model of intraepithelial neoplasia in the cervix.

METHODS AND RESULTS

Vocal cord biopsies of 45 patients with a broad spectrum of EHLL were reviewed. Detailed histological criteria were formulated for each of the four grades of EHLL in the Ljubljana classification, comprising simple hyperplasia (benign spinous layer augmentation), abnormal hyperplasia (benign basal and parabasal layer augmentation), atypical hyperplasia (risky for malignancy) and carcinoma in situ (actually malignant, but without invasion).

CONCLUSIONS

Using these criteria a high degree of concordance of histological diagnoses of grading levels for the Ljubljana classification was achieved between the pathologists of the Working Group. The system was found to be more precise for routine diagnostic work than the others in vogue. The different grades of the Ljubljana classification correspond to significantly different levels yielded in each grade by the semiobjective methods of quantitative morphometry and immunohistochemistry.

Spindle cell carcinoma of the larynx

The clinicopathological features of 14 laryngeal neoplasms consisting of spindle-shaped cells are presented. Light microscopy showed a variety of morphological patterns from that of pleomorphic sarcoma and fibrosarcoma to more loose vascular patterns. Immunohistochemistry revealed that the spindle-shaped cells had a positive keratin immunoreactivity in 8 of 14 cases, and also that some cases had a dual expression of keratin and vimentin filaments. Electron microscopy showed that spindle-shaped cells had epithelial ultrastructures. The results support the hypothesis that the spindle cell carcinomas are true carcinomas with mesenchymal metaplasia and that the spindle-shaped cells are part of the neoplasm and not benign, reactive fibroblasts. These lesions occurred mainly on the true vocal cords in elderly patients. The neoplasms were nearly all polypoid, and many also ulcerated. There is no significant difference in clinical behaviour between laryngeal spindle cell carcinomas and ordinary squamous cell carcinomas of the larynx, and the same treatment policy is therefore advocated. Being polypoid and therefore able to be surgically removed with relative ease, they may even present a more favourable clinical course.

Histological changes in the nasal mucosa in rats after long-term exposure to formaldehyde and wood dust

Wood dust is a well known nasal carcinogen in man, as formaldehyde is in rats. In certain occupational environments, combined exposure to wood dust and formaldehyde is common. Little is known about the effects of this combination. A pilot study was performed on four groups of Sprague-Dawley rats: one exposed to wood dust (25 mg/m3), another to formaldehyde (12.4 ppm) and a third to both wood dust and formaldehyde; the fourth group served a control group. After 104 weeks of exposure the nose and lungs were examined histologically. One well differentiated squamous cell carcinoma was found in the formaldehyde group. Squamous cell metaplasia was found significantly more often among the formaldehyde-exposed rats. Squamous cell metaplasia with dysplasia was most frequently observed, however, in the group exposed to both formaldehyde and wood dust. There were also significantly more rats with pulmonary emphysema in the groups exposed to wood dust than in the other groups.

Histological changes in the nasal mucosa in persons occupationally exposed to formaldehyde alone and in combination with wood dust

In the nasal mucosa of rodents, both formaldehyde and wood dust have proved to be carcinogenic. Wood dust is also a well-known nasal carcinogen in man. The effects of long-term exposure of humans to formaldehyde, however, are more obscure. In this investigation two groups of workers with well-defined exposure to formaldehyde and to formaldehyde and wood dust, respectively, were compared with a control group regarding histological changes in nasal specimens from the middle turbinate. Significant changes were found in the formaldehyde group but not in the group exposed to both formaldehyde and wood dust. No correlation was found between histological changes and duration of exposure, doses of exposure or smoking habits.

Occupational exposure to formaldehyde and histopathological changes in the nasal mucosa

To study the cytotoxic effect of formaldehyde on the human nasal mucosa 75 men with occupational exposure to formaldehyde or to formaldehyde and wood dust, were examined, looking particularly at early signs of irritative effects and histopathological changes in the nasal mucosa. All men underwent a medical examination and a nasal biopsy specimen was examined by a pathologist and graded from 0-8 according to the morphological changes. A high frequency of nasal symptoms, mostly a running nose and crusting, was related to exposure to formaldehyde. Only three men had a normal mucosa; the remainder had loss of cilia and goblet cell hyperplasia (11%) and squamous metaplasia (78%); in six cases (8%) there was a mild dysplasia. The histological grading showed a significantly higher score when compared with unexposed contents (2.9 v 1.8). There was no dose response relation, no malignancies, and no difference in the histological score between those exposed to formaldehyde or to formaldehyde and wood dust.

Evaluation of lip salivary gland biopsy in 21 patients with primary Sjögren's syndrome

Lip salivary gland biopsy was performed in 21 (20 female) patients, age 26 to 74 years, with primary Sjögren's syndrome. The procedure helped identify a patient group with many autoimmune phenomena, including hypergammaglobulinemia, autoantibodies, autoimmune thyroiditis, vasculitis, and immunocytoma. A marked association with the HLA-DR3 antigen was noted. It is concluded that lip salivary gland biopsy is a simple and safe procedure that makes possible the identification among non-RA patients with sicca symptoms those who have autoimmune disturbance. This patient group deserves close medical supervision in order to detect autoimmune disease that requires treatment, such as autoimmune thyroiditis and lymphoma.

Occupational formaldehyde exposure and the nasal mucosa

This study was undertaken to evaluate the possible cytotoxic effect of formaldehyde on the nasal mucosa in man. 38 men with an average age of 38 years and average exposure time of 10.5 years were studied. They were exposed to formaldehyde when processing laminae. All men passed a medical examination and a nasal biopsy. The histological findings were scored, 0-8, according to a system proposed by Torjussen. The findings were compared with a non-exposed reference group of 25 men (mean age 35 years). 35% of the exposed were smokers compared to 48% of the nonexposed. The average histological score was 2.8 for the exposed versus 1.8 for the non-exposed (p less than 0.05, Wilcoxon). The more common findings in the exposed were loss of cilia, goblet cell hyperplasia and squamous metaplasia. In four cases (11%) there was a mild dysplasia. Smoking had a slight modifying effect on the histological picture. The results indicate that the suspected precancerous findings in animal studies after exposure to formaldehyde might be present in workers exposed to formaldehyde at relatively low levels.

Video time-lapse microscopy of human laryngeal carcinomas in vitro

Twelve human laryngeal carcinomas and 14 normal vocal cord epithelia were studied in vitro by the method of tissue culture incorporating video time-lapse microscopy. Different events were photographed by taking 'stills' from the television monitor during play-back. Outgrowths from both tumour and normal explants formed only as monolayers. Mitoses were mainly found to be localized approximately mid-way between explant and the edge of the outgrowth. Some cells were seen to become suddenly active producing oscillating blebs and sometimes they detached themselves from the monolayer culture and changed appearance. This was more prevalent in the tumour cultures. In both tumour and normal cell cultures lymphocytes were observed and their normal chemokinetic movement was changed into a rapid chemotactic attraction by the presence of a mitotic epithelial cell. These lymphocytes appear to represent T-suppressor cells. The present study has shown that primary tissue culture can be a valuable tool in the study of laryngeal carcinoma. The interaction between mitotic tumour cells and lymphocytes may represent a transformation of T-lymphocytes into LAK cells.

Malignant mixed tumour. A salivary gland tumour showing both carcinomatous and sarcomatous features

Two malignant mixed tumours, in which both carcinomatous and sarcomatous features were present, are described. They arose in the palate in patients who had undergone surgery and irradiation for a pleomorphic adenoma at the same site 30 and 36 years previously. The histological differential diagnoses of recurrent benign pleomorphic adenoma, pleomorphic adenoma resembling mesenchymal tumour, and carcinoma in (ex) pleomorphic adenoma are discussed. On the basis of their positive reaction for keratin with specific monoclonal antibodies it is suggested that the myoepithelial cells are of epithelial origin. Immunohistochemical studies together with the histological appearance of the neoplasms indicate that the carcinomatous as well as the sarcomatous elements were derived from modified myoepithelial tumour cells. Irradiation may have been responsible for inducing a true malignant mixed tumour as distinct from the more common malignancy which may arise in pleomorphic adenoma, this being a simple carcinoma.

Nasal cuboidal metaplasia with dysplasia. Precursor to adenocarcinoma in wood-dust-exposed workers?

The histological study of the non-tumours nasal mucosa in 22 wood-workers with ethmoidal adenocarcinoma was carried out and special attention was paid to the presence of cuboidal metaplasia with or without dysplasia. The workers had been exposed to wood dust for an average of 38 years (range 18 to 55 years). In 19 cases cuboidal metaplasia was found and 16 of these also had dysplasia. In 10 cases there was a transitional zone with dysplastic cuboidal epithelium in continuity with the tumour. In 5 cases there was squamous metaplasia. The results indicate cuboidal metaplasia with dysplasia being a possible precursor to nasal adenocarcinoma in workers exposed to wood dust, similar to the findings of squamous metaplasia and squamous cell carcinoma in nickel workers.

Adenocarcinoma of the ethmoid sinuses. A review of 28 cases with special reference to wood dust exposure

Adenocarcinoma makes up only a small percent of all nasal and paranasal sinus carcinomas, and is most often found in the ethmoid sinuses. Adenocarcinoma of the ethmoid sinuses is known to be associated with exposure to wood dust. Twenty-eight patients with ethmoid adenocarcinomas were collected, mainly during the last decade from a region with approximately 900,000 inhabitants and with a large amount of furniture industries. There were 4 women and 24 men in the study. Twenty of the men were exposed to dust from hardwood for 20 to 55 years (mean, 40 years) which is in accord with other reports and supports data on the increased risk for workers of developing adenocarcinoma of the ethmoid sinuses when exposed to dust from hardwood. Radiologic diagnosis is necessary to delineate the extent of these tumours, and computerized tomography (CT) especially furnishes important information. Most patients received preoperative radiotherapy followed by surgery, 50% of them survived 5 years, which is in accord with other reports.

Cholesterol granuloma of the maxillary and frontal sinuses

5 cases of cholesterol granuloma are described, 3 within the maxillary sinuses and 2 within the frontal sinuses. The lesions arise from the mucosa and can be recognized on plain films and tomograms of the sinus as opacity, sometimes resembling a mucocele. Radical operation seems to give absolute cure without any recurrence. The pathogenesis is hemorrhage and/or filtration. The closed cavities of the paranasal sinuses provide favorable conditions for cholesterol to become dissociated from the lipoprotein complex and to precipitate and to give rise to a granulomatous reaction.

Nasal symptoms and histopathology in a group of spray-painters

Industrial workers more and more frequently seek medical advice for nasal and sinus symptoms that they attribute to occupational exposure. The present study comprised 10 paint-sprayers exposed to solvents (primarily toluene and isobutylacetate) and dust. The working environment was checked by an industrial hygienist and a careful clinical examination including biopsies from the nasal mucosa was carried out. The results revealed prominent nasal symptoms in 3 patients and 4 suffered from cough. The histological examination showed in no case a normal nasal mucosa. The histological grading showed a significantly higher score in the exposed group compared to a matched control group. However, no conclusive connection between the duration of exposure and the clinical symptoms and morphological changes was possible to make, which will necessitate an extended study to evaluate the exact importance of the duration of exposure. The study indicates the possibilities of an early presymptomatic detection of nasal mucosal disturbances and arises the question whether the existing TLVs are adequate in preventing damage to the nasal mucosa and adherent clinical symptoms.

Scanning electron microscopy of vocal cord hyperplasia, keratosis, papillomatosis, dysplasia and carcinoma

The vocal cord fine surface structure was examined by scanning electron microscopy (SEM), and the observations related to the light-microscopical (LM) findings after embedding and cutting. The SEM micrographs were assessed using a rating system based on 7 parameters. The proportion of "normal" and "abnormal" SEM areas varied within the respective histologic groups. There was, however, a significant difference between the SEM ratings in the group with hyperplasia-keratosis, with or without mild dysplasia, compared to the groups with severe dysplasia-carcinoma in situ and invasive squamous cell carcinoma. In the small number of cases with moderate dysplasia and juvenile laryngeal papilloma, the SEM ratings displayed pronounced disparity.

The role of smear cytology in laryngeal diagnosis

There may be great difficulty especially in diffuse lesions, in obtaining representative laryngeal biopsy specimens. Therefore the reliability of laryngeal smear cytology was evaluated in comparison with the histologic diagnosis. The cytologic specimens were taken during 520 microlaryngoscopic examinations (direct technique). The sensitivity of the direct cytologic method in the detection of moderate dysplasia, severe dysplasia-carcinoma in situ, and invasive carcinoma was 45% (17/38), 83% (59/71), and 93% (137/147), respectively. A false negative cytologic reading was more frequent after radiotherapy. The specificity of the direct cytologic technique in the detection of histologically "benign" lesions was 80% (210/264). In 23 patients cytologic smears were obtained at mirror laryngoscopy (indirect technique). Both the direct and indirect cytologic tests are easy to perform, quick, and may be of diagnostic value in laryngeal diagnosis, especially in screening examinations. However, cytology cannot supersede the histological examination of biopsy specimens.

Bilateral acute retinal necrosis

Four patients who experienced the sudden onset of anterior uveitis with large keratic precipitates and dense vitreous opacities developed confluent yellow-white swellings and exudates in the peripheral retina and sheathing and obliteration of retinal arteries. After absorption of the exudates, atrophic patches in the peripheral retina and a funnel-shaped retinal detachment with many tears appeared. Angiograms showed retinal edema, fluorescein leakage from the choroid in the affected areas, and perivasculitis of the retinal arteries. Although treatment seemed unable to alter the course of the disease, in one case the retina reattachment after vitrectomy and filling of the vitreous space with silicone oil. Histopathologic studies disclosed extensive atrophy and degeneration of the outer retinal layers and pigment epithelium and occlusion of the retinal vessels. An infection may trigger the uveitis, leading to an autoimmune sensitization against rods and cones that causes severe local immune-complex disease and retinal vasculitis.

Hyperplasia, keratosis, dysplasia and carcinoma in situ of the vocal cords--a follow-up study

Comparison of reported series of laryngeal lesions is complicated by the inconsistency in the terminology. The classification of these lesions should logically be based on the degrees of dysplasia, as this has a bearing on the prognosis. The material for this study consisted of 193 patients with hyperplasia and/or keratosis, with or without mild dysplasia (Group I), moderate dysplasia (Group II), and severe dysplasia and carcinoma in situ (Group III). They were treated over a 14-year period (1966-1979) at Linköping University Hospital. Of the 98 patients in Group I available for follow-up, 23 had repeat excisions. Moderate dysplasia developed in 3 patients, severe dysplasia in 2, and invasive carcinoma in another 2 within 3 and 3.5 years; they both underwent laryngectomy. Among the 24 patients in Group II available for follow-up, severe dysplasia developed in 3 and invasive carcinoma in 3 up to 13 years after the initial diagnosis, all but one (with severe dysplasia) received a full course of radiotherapy, on one case total laryngectomy was subsequently performed for recurrent carcinoma. Of the 39 patients with severe dysplasia and carcinoma in situ 16 were given primary radiotherapy; 4 of these developed invasive carcinoma; 3 of them underwent total laryngectomy and one partial laryngectomy. Excision or stripping of the vocal cords was the primary treatment in 23 cases; 5 of these developed invasive carcinoma; 2 of them underwent total laryngectomy. Diffuse lesions and well differentiated forms of severe dysplasia caused most problems and had the highest incidence of invasive carcinoma irrespective of the form of treatment. Patients with hyperplasia, keratosis, dysplasia and carcinoma in situ should be carefully followed up, as invasive carcinoma may develop many years after the initial diagnosis.

HISTOSCAN: computer program for cytophotometry in tissue sections and its application in the evaluation of nuclear atypia

The grading of nuclear atypia has a great and well recognized value when predicting the malignancy of neoplastic processes. Although the basic criteria for the grading are generally agreed upon, in the individual case, the final judgement is to some extent still a matter of subjectivity, which naturally impairs reproducibility. The present paper describes a method for quantification of variability of nuclear size and Feulgen-stainability. By plotting the mean optical density against the area value in a scatter-diagram, a cluster is obtained, the size of which reflects the degree of nuclear atypia. The measurements are performed in tissue sections using stage scanning cytophotometry. A computer program--HISTOSCAN--has been developed which enables measurements in highly cellular tissues. The system is also insensitive to the influence of light scattering, a factor of importance when measuring in tissue sections. The performance of the program is tested in both imprints and tissue sections.

Photometric evaluation of laryngeal epithelium exhibiting hyperplasia, keratosis and moderate dysplasia

Photometric examination of vocal cord epithelia disclosed no difference in the nuclear DNA content or nuclear area of normal and keratotic laryngeal epithelia. For 2 out of 3 epithelia displaying hyperplasia the values were slightly elevated. There seem to be no morphologic or photometric grounds for considering either hyperplasia or keratosis to be premalignant. Eight patients with moderate dysplasia were selected; 3 with and 5 without subsequent development of severe dysplasia or carcinoma in situ. In all 8 cases the DNA values were not increased, but in 6 there was an increased variation about the mean. There were no morphologic or photometric differences between the epithelia subsequently developing severe dysplasia or carcinoma in situ and those that did not. The 3 patients developing severe dysplasia or carcinoma in situ were then followed for 112, 27 and 106 months and showed no evidence of invasive carcinoma. The other 5 patients with moderate dysplasia were followed for 48 to 123 months without any sign of recurrent disease. There are no photometric grounds for considering moderate dysplasia as a precancerous lesion. Long-term investigation is required to ascertain the risk that carcinoma in situ or invasive carcinoma will develop in patients with laryngeal hyperplasia, keratosis and moderate dysplasia.

Chondrosarcoma of the larynx

A chondrosarcoma arising in the posterior cricoid plate is presented. The tumour gave rise to increasing inspiratory stridor: laryngectomy was performed. The tumour consisted of loose cartilaginous tissue with great predominance of highly differentiated cartilage cells and only small areas with nuclear polymorphism. This complicated the differential diagnosis between chondroma and highly differentiated chondrosarcoma. From the fact that the patient died from massive pulmonary metastases 3 1/2 years later, it is evident that the degree of malignancy of cartilaginous tumours should be determined even on small polymorphic foci. The DNA histogram for the foci of the laryngeal tumour with atypia differed distinctly from those for benign chondroma and normal cartilage, but resembled those of the pulmonary and splenic metastases and of a nasal chondrosarcoma. Photometric examination may provide an aid in the difficult differential diagnosis between chondroma and highly differentiated chondrosarcoma.

Toluidine blue. An aid in the microlaryngoscopic diagnosis of glottic lesions?

The value of toluidine blue staining in vivo in the diagnosis of glottic lesions was examined by comparing the results obtained in a series with the histological findings. This material included 272 biopsy specimens from the vocal cords (202 microlaryngoscopic examinations). In 148 of these, the changes were classified as "malignant" (moderate and severe dysplasia and carcinoma) and in 124 as "benign." The sensitivity of the staining test in detection of malignant lesions was 91%. Among 13 false-negative results (9% of the malignant group), there was keratosis in 11. The overall specificity of the staining tests was 52%. The false-positive lesions displayed "benign" pathological alterations, such as inflammation and ulceration. False-positive findings were more common after radiotherapy. A correct diagnosis of malignancy on the basis of positive staining was more frequent the greater the intensity of staining.

Amyloidosis of the larynx

Amyloidosis of the larynx is a rare disease, accounting for less than 1% of all benign laryngeal 'tumours'. Three cases of this type of lesion are reported--one of the vocal cord, one of the false vocal cord and one of the subglottis and trachea. In 2 of the patients the amyloidosis was localized, while the third was later found also to have an epipharyngeal solitary plasmacytoma with amyloid deposits and in addition amyloidosis of the nasal cavity. However, the amyloidosis in this patient may still be regarded as being localized, as the clinical examination and laboratory tests afforded no evidence of generalized disease. Amyloidosis of the larynx may be manifested as a localized tumour or as a diffuse infiltration. The symptoms and signs will, of course, depend on the site of the amyloid deposit. When the vocal cords are involved hoarseness may result, and this was the most prominent sign in the present cases. The treatment of laryngeal amyloidosis is primarily by endoscopic excision. Amyloid substance has specific staining properties. The Congo red reaction with a green birefringence in polarized light and Phorwhite BBU using fluorescence microscopy are regarded as the most reliable staining reactions. Electron microscopy has revealed a typical fibrillar structure of amyloid.

The DNA content and nuclear size in normal, dysplastic and carcinomatous laryngeal epithelium. A spectrophotometric study

The aim of the present study was to obtain a more objective evaluation of nuclear hyperchromasia and polymorphism in laryngeal epithelium. The method is based on a photometric assay of nuclear size and DNA content in Feulgen stained slides. The DNA content of hyperchromatic nuclei should exceed the mean for nuclei of normal epithelium by more than twice the standard deviation. In comparison with lymphocytes (2N) the DNA content in hyperchromatic nuclei corresponds to 3.3 N. The mean DNA contents of normal, dysplastic and carcinomatous laryngeal nuclei were 69, 71 and 118 A.U. The mean nuclear area for normal, dysplastic and carcinomatous epithelial cells were 48, 41 and 73 micrometer2. The higher the degree of atypia displayed by the cells the greater was the variability of the DNA content and the nuclear size. The investigation shows that the method may provide a more objective basis for evaluating hyperchromasia and polymorphism.

Cardiac haemangio-endotheliosarcoma. Review of the literature and report of a case

A case of primary haemangio-endotheliosarcoma of the right atrium is reported. A review of the literature is given and in all but four of the 56 cases, the tumour originates in the right atrium projecting into the cavity. This explains why these tumours present a rather uniform clinical picture characterized by superior vena caval syndrome combined with pericardial effusion, cardiomegaly, dyspnoea and chest pain. A male dominent sex distribution of 3 to 1 is found. The tumour is highly malignant and has caused death within an average of six months. We emphasize the possibility of early diagnosis particularly since eht clinical symptoms are rather typical and cases are reported where therapy apparently was successful.