BackgroundCryptogenic organizing pneumonia (COP) is a clinicopathological syndrome of unknown origin. Corticosteroids are the standard treatment, but clarithromycin (CAM) is also effective. The aim of this observational retrospective study was to compare the results of CAM versus prednisone (PRE) treatment in patients with biopsy-proven OP without respiratory insufficiency.Material and methodsIn a 15-year period, 40 patients were treated with CAM (500 mg twice daily orally for 3 months) and 22 with PRE (mean initial dose of 0.67 ± 0.24 mg/kg/d for a mean of 8.59 ± 3.05 months).ResultsThe clinical presentation, laboratory, and radiological findings did not differ markedly between patients treated with CAM and PRE, with the exception of a higher frequency of sweats (55% vs. 23%; p < 0.015), ground glass opacities (95% vs. 50%; p <0.0001) and nodular lesions (45% vs. 18%; p = 0.036) in the CAM group. A complete response was achieved in 35(88%) patients treated with CAM and in all treated with PRE. Patients treated with PRE relapsed more frequently than those treated with CAM (54.5% vs. 10%; p < 0.0001). Corticosteroid-related adverse events were noticed in 8(6.5%) patients (with one death), but CAM caused only one (2.5%) allergic reaction. A FVC >80% identified patients who might be successfully treated with CAM with a sensitivity of 60% and a specificity of 88.57% (AUC 0.869; 95% CI 0.684–1; p = 0.008); the figures for the FEV1 were >70%, a sensitivity of 60%, and a specificity of 91.43% (AUC 0.809; 95%CI 0.609–1; p = 0.027).ConclusionsCAM can be used to treat COP patients in whom the pulmonary function parameters are within normal limits. Such therapy is shorter, better tolerated, and associated with fewer adverse events and relapses than is PRE. However, the therapy is ineffective in some patients.

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A 62-year-old, obese woman, smoking 10 pack/year was admitted to the National Tuberculosis and Lung Diseases Research Institute to diagnose small, round opacities revealed by routine chest X-ray examination. These lesions had been observed for 5 years. The patient had been treated for psoriasis, hypertension, and insulin-independent diabetes. On admission she was in good condition, complaining of a slight productive cough as well as intermittent osteoarticular pain. Physical examination revealed cutaneous psoriatic lesions, slight edema of the lower limbs, and clubbed fingers. Tuberculin test was positive. Chest Computer Tomography scanning showed partially calcified nodules (up to 1cm in diameter) located in the middle and base areas of both lungs. No evidence of hilar nor mediastinal lymph node enlargement was seen. Lung specimens displayed intraalveolar and intravascular growth of neoplastic cells. Immunohistochemical expression of Factor VIII, CD31 and CD34 antigens was present. Pulmonary epithelioid haemangioendothelioma was diagnosed. After 6 months of observation, progression of the disease was shown. Interferon alpha treatment was introduced. During the therapy, a slight regression of pulmonary changes was noticed and since then stabilization of the disease was observed.

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Introduction: Histopathological diagnosis of malignant mesothelioma (MM) and differentiating it from tumors infiltrating the pleura is very difficult. Distinguishing benign reactive mesothelial cell proliferation from MM also presents problems. The objective of this study was to evaluate the significance of selected immunohistochemical stains in differentiating MM from non-small cell lung cancers infiltrating the pleura and from benign reactive mesothelial cell proliferation. Material and methods: The material encompassed 86 cases of MM, 54 cases of NSCLC infiltrating the pleura, and 43 cases of benign reactive mesothelial cell proliferation. The MM cases were reclassified according to the WHO criteria (2004): epithelioid, 61 cases (71%), including well-differentiated papillomatous, 3 cases; sarcomatous, 6 cases (6.8%); fibrous, 4 cases (4.7%); biphasic, 15 cases (17.5%). A panel of immunohistochemical stains was used in this study. It included broad-spectrum antibodies to cytokeratins (CKAE1/AE3, CKMNF116), vimentin, epithelial membrane antigen (EMA), mesothelial cells (HBME1, CK5/6, calretinin), adenocarcinoma cells (BerEp4, B72.3, CEA, TTF1), antibodies enabling the assessment of proliferation (Mib1) and cell-cycle regulating proteins (p53). Results: Coexpression of cytokeratins and vimentin was found in 63.9% of MM cases and cell-membrane reactions with EMA were seen in 58.9%. Positive staining for HBME1, CK5/6, calretinin, BerEp4, B72.3, CEA and p53 was obtained in 76.7%, 51.2%, 66.7%, 1.2%, 6.2%, 1.2% and 51% of the cases, respectively. None of the MM cases stained for TTF1. MM by WHO subgroups: Coexpression of cytokeratins and vimentin occurred in 55.7% cases of epithelioid MM, 93.3% of biphasic MM, 66.6% of sarcomatous MM, and in 100% of fibrous MM cases. Positive staining for HBME1, CK5/6, and calretinin was seen only in the epithelioid and mixed subtypes of MM; the respective percentages of positive reactions were: HBME1, 90.2% and 73.3%; CK5/6 58.2% and 53.3%; calretinin, 72% and 75%. Non-small cell lung cancers infiltrating the pleura: Coexpression of cytokeratin and vimentin was found in 17.6% of the cases, positive staining of membranes for EMA, in 13% cases. Positive staining for HBME1 was observed in 22.6% of the cases, for CK5/6, in 9.3%, for calretinin, in 2%, for BerEp4, in 72.2%, for B72.3, in 64.1%, for CEA, in 58.5%, and for TTF1, in 43.8%. Benign reactive mesothelial cell proliferation: Protein p53 was present in 9.3% of cases, whereas no positive staining for EMA was found. Differentiation of MM from non-small cell carcinomas: Among the antibodies used in the study, anti-HBME1 had the highest sensitivity (76.7%) but lowest specificity (77.4%). Staining for calretinin showed high specificity (99.8%), as did CEA and TTF1 (98.8% and 100%), with moderate sensitivity (66.7%, 58.5% and 43.8%, respectively). BerEp4 showed the highest sensitivity (72.2%) and specificity (98.8%). Conclusions: In diagnosing mesothelioma it is necessary to use a panel of immunohistochemical stains, which should contain antibodies to markers for adenocarcinoma and mesothelioma. Due to the high costs of such a study, a two-stage method is advantageous. The best combination of sensitivity and specificity was found for BerEp4, CEA, and TTF1 and for calretinin and HBME1. In the diagnosis of spindle-cell pleural tumors and the fibrous form of MM and benign reactive mesothelial cell proliferation , markers of mesothelial cells are noncontributory. Immunohistochemical staining fails to identify a reactive process, but a diffuse, positive stain for EMA and the presence of protein p53 support the diagnosis of MM.