Image analysis derived ploidy and proliferation indices in soft tissue sarcomas: comparison with clinical outcome

Principles of ploidy analysis by static cytometry

Aims-To examine the basic assumptions made during DNA ploidy analysis of histological sections with an aim to eliminate methodological errors that have lead to conflicting results with this technique.Methods-A rat liver imprint and histological sections together with sections and whole nuclei cytospins of human breast tumour biopsy specimens were stained with azure A Schiff's reagent and used to investigate the effects of computer imaging, histological section thickness, nuclear volume, and shape corrections.Results-The rat liver imprint demonstrated a linear relation between mean nuclear transmittance and nuclear area for each of the three (2C, 4C, 8C) hepatocyte clusters. This finding was used to produce similar, proportional integrated optical density (IOD) measurements from rat liver sections by selecting only nuclei that were sectioned through their centres, as assumed by the mathematics for volume correction. The limitations of computer imaging necessitated an edge (glare) correction for each nucleus so that nuclei of different sizes could be analysed. Shape correction was required to analyse nuclei of different morphologies. Normal human lymphocytes, squamous epithelium and fibroblasts were all measured with similar IODs. DNA ploidy values obtained from 7 mum human breast tumour sections (using lymphocytes as controls) correlated well with those obtained from the whole nuclei cytospins from the same tissue blocks.Conclusions-With an improved understanding of the theoretical and technical aspects of ploidy analysis of tissue sections, reproducible and consistent results are possible. These results can be integrated into routine histopathology investigations alongside immunohistochemistry and molecular diagnostic techniques.

Diagnosis of soft tissue tumors by fine-needle aspiration with combined cytopathology and ancillary techniques

The diagnosis of mesenchymal neoplasm by fine-needle aspiration biopsy (FNAB) has presented a diagnostic challenge. Most reports claim an accuracy approaching 95%, but while they distinguish benign and malignant lesions, the most problematic group, the intermediary malignant group, is omitted. The purpose of this study was to determine whether rapid cytologic diagnosis of soft-tissue tumors could guide surgeons in therapeutic decisions without the need for a tissue biopsy. Ninety-four FNA cytologic specimens were examined by the National Soft Tissue Consortium of Hungary and compared with the corresponding histology. Ordinary lipomas were excluded. Morphologic evaluation was supplemented by ancillary techniques such as fluorescence in situ hybridization (FISH), DNA cytometry, and immunocytochemistry. From a practical clinicopathological point of view, the cases were grouped in the following categories: 1) tumors with definitive diagnosis: a) high-grade malignant neoplasms (high-grade sarcomas, metastatic carcinomas, lymphoma), b) tumors with precise histogenetic origin by cytogenetics, c) benign tumors; 2) tumors of questionable nature. In the first group there were 74 tumors: 22 high-grade sarcomas, six metastatic carcinomas, one malignant lymphoma, 16 malignant tumors in which the precise histogenetic origin could be established by cytogenetic studies, and 29 benign soft-tissue tumors other than lipomas. In the second group there were 20 tumors comprising benign and malignant soft tissue tumors of low grade, wherein the precise nature of the neoplasm could not be established with confidence on cytologic study, even using ancillary techniques. FNAB of soft-tissue tumors combined with ancillary techniques should be considered a viable diagnostic technique for therapeutic protocols. Although the second group is fairly large, we have reliable, well-characterized categories which provide great freedom for preoperative and surgical treatment, thus providing the best chance for healing.

Fine-needle aspiration of triton tumor: morphology, immunohistochemistry, electron microscopy, and cell image analysis

A single a case of malignant triton tumor, presented as a neck mass in a 34 year old female diagnosed solely by fine needle aspiration, is reported. The diagnosis was supported by immunohistochemical staining and electron microscopic examination that showed evidence of both schwannian and rhabdomyoblastic differentiation. Cell image analysis was also performed on the case and showed an aneuploid peak with a DNA index of 1.7. Diagnosing rare tumors with fine needle aspiration is feasible; particularly with the help of ancillary studies.

Comparison of ploidy analysis by flow cytometry and image analysis in hydatidiform mole and non-molar abortion

Determination of DNA ploidy is useful in the diagnosis and classification of hydatidiform mole. Most reports of ploidy analysis in molar tissue have used DNA flow cytometry. Although image analysis cytometry offers theoretical advantages over flow cytometry, there have been few reports of ploidy analysis by image analysis in hydatidiform mole. We selected 47 cases and measured DNA ploidy by flow cytometry and image analysis cytometry in complete hydatidiform mole, partial hydatidiform mole and non-molar abortion. The two cytometry modalities were compared using kappa statistics. There was reasonable overall agreement between the two modalities (kappa = 0.69) and when ploidy was stratified into diploid/polyploid and triploid categories there was near perfect agreement (kappa = 0.93). Aneuploid cell populations, which were not evident on flow cytometry, were identified by image analysis in a significant proportion of complete and partial hydatidiform moles and in a small number of non-molar abortions. Flow cytometry and image analysis cytometry yield comparable ploidy information, useful in the diagnosis and classification of hydatidiform mole. Image analysis cytometry offers greater sensitivity in the detection of small non-diploid cell populations but the significance of this latter finding is uncertain.

Aneuploidy in atypical fibroxanthoma: DNA content quantification of 10 cases by image analysis

It has recently been reported that atypical fibroxanthoma (AFX) is a predominantly diploid lesion in contrast to malignant fibrous hystiocytoma (MFH) which is usually aneuploid. To test this hypothesis, DNA content quantification was undertaken on Feulgen-stained cytology and tissue section preparations from 10 cases of AFX by image analysis. The large atypical cells which characterize AFX were aneuploid in each case. Smaller spindle-shaped cells found in this lesion were diploid. The results suggest that AFX is indistinguishable from MFH by DNA content estimation and highlight an advantage of image analysis over flow cytometry.