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.