alcian-blue and Mesothelioma

Synovial sarcoma of the pleural cavity is exceptionally rare and may be confused, both clinically and histologically, with malignant mesothelioma, with subsequent inappropriate therapy. To address this dilemma, four biphasic synovial sarcomas (BSSs) and four biphasic malignant mesotheliomas (BMMs) were studied with a panel of mucin and immunohistochemical stains to determine if they would allow one to distinguish between the two. The BMMs were all pleural-based. The BSSs were extrapleural. The mucin and immunohistochemical stains were all performed on formalin-fixed, paraffin-embedded tissue using standard techniques, with appropriate positive and negative controls. Mucin present in BSS is, in general, mucicarmine-positive and resistant to both hyaluronidase and diastase. Of the immune markers evaluated, only calretinin, Ber-Ep4 and bcl-2 were of limited discriminatory value. Subsets of cytokeratins, CEA and CD 34 were not helpful. With the exception of bcl-2, the apoptotic markers p53, bax and cpp32 (caspase) also were not useful. However, when the apoptotic stains were viewed collectively, variations in expression between the two tumours raised the possibility that alterations in apoptotic activity might be responsible for their pathogenesis and behavior. The diagnosis of BSS or BMM of the pleural should be made only after total consideration of clinical, radiological, histochemical and immunohistochemical findings. Although mucin stains are useful in differential diagnosis, reliance solely on immunohistochemical markers, with the possible exception of calretinin, Ber-Ep4 and bcl-2, is not dependable. The role of apoptosis in the pathogenesis of these tumours needs to be explored with a much larger series.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Alcian Blue; Apoptosis; Biomarkers, Tumor; Female; Humans; Immunohistochemistry; Male; Mesothelioma; Middle Aged; Mucins; Neoplasm Recurrence, Local; Neoplasms, Multiple Primary; Periodic Acid-Schiff Reaction; Pleural Neoplasms; Sarcoma, Synovial; Staining and Labeling

Topics: Alcian Blue; Animals; Cricetinae; Hyaluronoglucosaminidase; Immunohistochemistry; Keratins; Male; Mesocricetus; Mesothelioma; Periodic Acid-Schiff Reaction; Peritoneal Neoplasms; Rodent Diseases; Staining and Labeling; Vimentin

The immunohistochemical reactivity of 38 mesotheliomas and 44 adeno-carcinomas or large cell carcinomas of the lung with monoclonal antibodies (MAb) B72.3 and Leu M1 was compared with their reactivity with the routine histochemic stains periodic acid-Schiff with diastase digestion (PAS-D) and alcian blue +/- hyaluronidase. Both MAbs reacted selectively with carcinomas when a positive test was set at greater than or equal to 10% reactive tumor cells. However, MAb B72.3 reacted with significantly more of the carcinomas (86%, chi-square test, P less than 0.01) and bound to a greater percentage of tumor cells (47 +/- 28%; mean +/- SD, t-test, P less than 0.001) than Leu M1 (57% and 25 +/- 28%, respectively). The similar reactivities of surgically resected tumor specimens and post mortem tissues with both antibodies confirmed antigen stability and suggested broad clinical utility. PAS-D stained 61% of the carcinomas. Using the markers for carcinomas (PAS-D, B72.3, and Leu M1), the tumors were classified into the correct group in 80 of 82 (98%) cases (95% confidence level: greater than 92% accuracy). The alcian blue stain was useful to confirm a diagnosis of dimorphic or epithelial mesothelioma (48% were positive).

Topics: Adenocarcinoma; Aged; Alcian Blue; Antibodies, Monoclonal; Carcinoma, Small Cell; Cytoplasmic Granules; Diagnosis, Differential; Female; Humans; Immunoenzyme Techniques; Lung Neoplasms; Male; Mesothelioma; Middle Aged; Mucins; Periodic Acid-Schiff Reaction