Nuclear DNA measurements of metastatic melanoma by a computerized digital imaging system

Analysis of nuclear DNA and morphometry, and proliferating cell nuclear antigen in primary and metastatic malignant melanoma

Sections from 23 primary malignant melanomas and 39 corresponding metastases were analysed for DNA content, nuclear morphometry, and proliferating cell nuclear antigen (PCNA). In 15 of 23 patients (65%) both primary and secondary tumours showed similar DNA patterns, whereas a disparity was found in the remaining eight patients (35%). The 23 primary tumours and groups of metastases (from different patients) located in skin, lymph nodes, and brain did not differ significantly in any of the variables investigated. Cox stepwise regression analysis indicated that a large variability (CV) of nuclear area in the first metastasis correlated with increased survival after recurrence (p = 0.039) as well as with survival (p = 0.031).

DNA image cytometry on sections as compared with image cytometry on smears and flow cytometry in melanoma

DNA measurements of 130 melanomas were carried out by flow cytometry (FCM) and image cytometry (ICM). ICM was applied to cytological preparations of fresh material (cICM) and to sections of formalin-fixed paraffin embedded tissue (sICM). The DNA ploidy, the DNA index of G0/G1 peaks (DI), and the proliferation index (PI) were used to compare all the methods. The following parameters reflecting malignancy were calculated only from ICM histograms: the 5c exceeding rate (5cER) and the malignancy grade (MG). In cases found to be DNA aneuploid by FCM, the PI values (FCM versus cICM) and the DIs (between all methods) showed a high correlation, and the concordance in relation to the DNA ploidy status was 96% (FCM versus cICM) and 94% (FCM versus sICM). However, we ascertained essential differences between FCM and ICM in melanomas classified as DNA diploid by FCM. The concordance in DNA ploidy was only 66% (FCM versus cICM) and 64% (FCM versus sICM). In contrast, cICM and sICM yielded similar results in most cases. With the exception of the near diploid range, ICM is superior to FCM in detecting DNA aneuploidy. In particular, DNA tetraploid stem lines can easily be overlooked by FCM. Therefore, DNA measurements of tumours judged to be DNA diploid by FCM must be verified by ICM. ICM on sections proved to be applicable and yielded reliable results provided that a suitable thickness was used, and the measuring of sectioned and overlapping nuclei was largely avoided by careful focusing in either direction.

Image analysis in dermatopathology

BACKGROUND/AIMS

Image analysis in dermatopathology has been used for DNA ploidy analysis, morphometry, stereology, and quantitative immunohistochemistry. The object is to review image analysis in dermatopathology and evaluate these modalities and their application in pigmented lesion pathology, for elucidation of tumor behaviour and architecture and as an aid in tumor identification and prognostication.

CONCLUSION

Image analysis in dermapathology has a huge potential. The techniques are difficult and at present mainly used in specialized centres.

Prognostic significance of DNA cytometry in comparison with histologic measurements in malignant melanomas

In the present study we evaluated the prognostic impact of both DNA cytometry and quantitative histology in patients with malignant melanoma (MM). In contrast to previous investigations on sections, rapid image analysis (IA) of imprint specimens was performed to measure DNA cytometric features; 34 cases of stage I MM with low (< 1.5 mm, n = 20) and higher tumor thickness (TTH) (> 1.5 mm, n = 14) were analyzed. We found significant correlations between cytometric features and TTH, which is accepted as the most important prognostic criterion in MM. Higher TTH was closely correlated with the rate of markedly aneuploid nuclei, which is indicated by the 5c exceeding rate (5cER; r, 0.89; p < 0.001). The gain of chromatin in thicker tumors was accompanied by higher mean nuclear area (MAREA; r, 0.60; p < 0.001) and mean DNA content (MDNA; r, 0.58; p < 0.001). Additional evidence for prognostic significance of cytometry was obtained by preliminary survival analysis of 16 cases (four patients died within 2 1/2 years and 12 patients survived for at least 4 1/2 years). Applying multivariate stepwise discriminant analysis, a combination of TTH, level of invasion (LEV), 2c deviation index (2cDI), and modified standard deviation of the DNA values (SDNAM) proved to be most effective. One hundred percent of the cases were correctly classified as survivors or nonsurvivors. TTH and the 5cER were found to be the best univariate criteria for prognosis. In the U test according to Mann and Whitney, a significant discrimination of survivors and nonsurvivors was possible using either TTH or the 5cER, respectively (p < 0.02). Thus, we would like to conclude that IA of imprint specimens can be recommended as a rapid and simple additional method for grading.

Deoxyribonucleic acid ploidy studies in choroidal melanomas

In several tumors of different organ sites, the amount of DNA in a cell (ploidy) is associated with malignancy. We performed DNA quantitation in 21 choroidal melanomas and compared flow cytometry with image analysis in 11 of these melanomas. We modified our preparation technique to overcome problems with pigment and control cell populations in the image analysis group. Fifteen tumors were diploid and two tumors were tetraploid. Four tumors were unprocessable by flow cytometry, but two of these tumors were diploid by image analysis. Image analysis also detected tetraploidy in two tumors that were diploid by flow cytometry. During image analysis, cells were classified according to the Callendar classification and histograms were plotted for each cell type. All spindle A cells were diploid and most tetraploid peaks were formed by epithelioid cells. The use of image analysis on small samples of choroidal melanomas may be of value both in confirmation of diagnosis and prognosis of these lesions, and perhaps therapeutically, for example, in the monitoring of radiation treatment.

Management of the regional lymph nodes in patients with cutaneous malignant melanoma

One of the most difficult decisions in the management of patients with melanoma remains whether or not to dissect electively the regional lymph nodes of patients with high risk primary tumors. There is abundant evidence that a proportion of such patients will eventually develop nodal metastases and that the probability of metastasis increases with increasing tumor thickness and depth of invasion. If elective node dissection is performed on all patients with high risk primaries, most patients (who have no tumor in the nodes) will be subjected to a potentially morbid operation from which they can achieve no benefit. On the other hand, a "wait and see" policy accepts that a minority of patients will go on to develop nodal metastases and that if definitive therapy is delayed until metastases are detected clinically their likelihood of survival is much reduced. We describe a new technique of dye-directed selective lymphadenectomy that allows accurate and objective identification of individual patients who have subclinical metastases, the individuals who a priori are most likely to benefit from lymphadenectomy. We also discuss new approaches to the assessment of prognosis after lymphadenectomy for node-spread melanoma, a group of patients in whom the prognosis is not uniformly bad. We end with a consideration of quality assurance aspects of the pathological evaluation of lymphadenectomy specimens.