Flow cytometric analysis of lymphocyte profiles in mediastinal lymphadenopathy of sarcoidosis.

Lymphocyte profiles in mediastinal lymph nodes may reflect the immune status of patients with sarcoidosis. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is useful for the diagnosis of diseases with mediastinal lymphadenopathy including sarcoidosis. The purpose of this study was to determine lymphocyte profiles of lymph nodes in sarcoidosis by analyzing EBUS-TBNA samples. We prepared single cell suspensions from EBUS-TBNA samples of mediastinal lymph nodes from patients with sarcoidosis or lung cancer and analyzed surface markers (CD3, CD4, CD8, CD19, CD25) and FoxP3 expression in the resultant lymphocytes using flow cytometry. We studied 26 patients with sarcoidosis and 16 with lung cancer with mediastinal lymph node metastases. In sarcoidosis, the CD4/CD8 ratio was significantly more elevated in lymph nodes than in bronchoalveolar lavage fluid (P<0.001), although both were strongly correlated. The CD4/CD8 ratio was significantly higher in stage I than in stage II both in the BAL fluid and lymph nodes. When compared with lung cancer lymph node metastasis, the CD4/CD8 ratio was significantly higher in sarcoidosis, whereas the CD3/CD19 ratio was significantly higher in lung cancer. The proportion of regulatory T cells (CD4+, CD25+, FoxP3 high) did not differ between sarcoidosis and lung cancer samples. Lymphocyte profiles in mediastinal lymphadenopathy can be analyzed by flow cytometry of EBUS-TBNA samples. These findings might help elucidate the immunopathology of sarcoidosis.

A solitary mediastinal mass due to localized AL amyloidosis: case report and review of the literature.

AL amyloidosis presenting as a solitary mediastinal mass is a rare occurrence, with only a few cases reported in the literature. We describe a case of a man presenting with a mediastinal mass diagnosed as amyloidosis, confirmed by mass spectrometry to consist of lambda light chains. Here we review the literature and discuss treatment options for this rare entity.

[PET-CT in thoracic disease]. / TEP-TDM et thorax.

PET-CT imaging merges metabolic data obtained after injection of a tracer labelled with a positron emitter, with CT anatomical data. This whole-body technique provides (i) an improved spatial resolution and (ii) when the tracer is ¹8FDG, quantification of tissue glucose metabolism. In thoracic oncology, ¹8FDG PET-CT imaging allows diagnosis, staging, follow-up of treatment efficiency, and detection of recurrence. Furthermore, its potential usefulness in inflammatory and infectious diseases should be emphasized. Its main contra-indication is pregnancy, and a good knowledge of its technical procedure is mandatory. The most currently used quantification index is the standardized uptake value (SUV), whose interpretation requires caution.

Rosai-Dorfman disease presenting as a solitary mediastinal mass.

Rosai-Dorfman disease (RDD) involving an extranodal site is a diagnostic challenge. Reported herein is the case of a 67-year-old man who presented with a solitary superior mediastinal mass. The lesion was clinically suspected of malignancy including lymphoma because of its high uptake during a (67)Ga-scintigram and (18)F-fluorodeoxyglucose-positron emission tomography. There was no evidence of spread of the disease. Histology of thoracoscopic biopsy specimens indicated granulomatous lesion with infiltration of lymphocytes, plasma cells, and histiocytes with lymphocytes engulfed in their cytoplasm. The lesion did not contain lymph node or thymic elements. On immunohistochemistry the histiocytes were positive for S-100 protein, CD68, and CD163 but were negative for CD1a. These findings suggested a diagnosis of RDD. Despite lack of intervention, the lesion remained almost the same size for 3 years. To the best of the authors' knowledge this is the first case of RDD presenting as a solitary mediastinal mass.

18F-FDG accumulation with PET for differentiation between benign and malignant lesions in the thorax.

UNLABELLED: Recent reports have indicated the value and limitations of (18)F-FDG PET and (201)Tl SPECT for determination of malignancy. We prospectively assessed and compared the usefulness of these scintigraphic examinations as well as (18)F-FDG PET delayed imaging for the evaluation of thoracic abnormalities. METHODS: Eighty patients with thoracic nodular lesions seen on chest CT images were examined using early and delayed (18)F-FDG PET and (201)Tl-SPECT imaging within 1 wk of each study. The results of (18)F-FDG PET and (201)Tl SPECT were evaluated and compared with the histopathologic diagnosis. RESULTS: Fifty of the lesions were histologically confirmed to be malignant, whereas 30 were benign. On (18)F-FDG PET, all malignant lesions showed higher standardized uptake value (SUV) levels at 3 than at 1 h, and benign lesions revealed the opposite results. Correlations were seen between (18)F-FDG PET imaging and the degree of cell differentiation in malignant tumors. No significant difference in accuracy was found between (18)F-FDG PET single-time-point imaging and (201)Tl SPECT for the differentiation of malignant and benign thoracic lesions. However, the retention index (RI) of (18)F-FDG PET (RI-SUV) significantly improved the accuracy of thoracic lesion diagnosis. Furthermore, (18)F-FDG PET delayed imaging measuring RI-SUV metastasis was useful for diagnosing nodal involvement and it improved the specificity of mediastinal staging. CONCLUSION: No significant difference was found between (18)F-FDG PET single-time-point imaging and (201)Tl SPECT for the differentiation of malignant and benign thoracic lesions. The RI calculated by (18)F-FDG PET delayed imaging provided more accurate diagnoses of lung cancer.

Idiopathic fibroinflammatory (fibrosing/sclerosing) lesions of the mediastinum: a study of 30 cases with emphasis on morphologic heterogeneity.

The clinicopathologic and immunohistochemical findings in 30 cases of idiopathic fibroinflammatory lesions of the mediastinum are presented. There were 17 male and 13 female patients between 10 and 64 years of age; 19 were African-American, and 10 were Caucasian. Clinically, respiratory and/or systemic symptoms including cough, shortness of breath, and fever were present in 28 patients. Five patients also presented with evidence of superior vena cava syndrome. All of the lesions involved the anterior mediastinum with radiographic evidence of hilar and paratracheal involvement in nine and five patients, respectively. Histologically, the lesions were characterized by an inflammatory fibrosing process that showed three distinctive histologic patterns. On the basis of the histologic pattern, they were subdivided into three distinct groups (stages). Stage I demonstrated edematous fibromyxoid tissue with numerous spindle cells, eosinophils, mast cells, lymphocytes, plasma cells, and thin-walled blood vessels; Stage II showed thick glassy bands of haphazardly arranged collagen with focal interstitial spindle cells, lymphocytes, and plasma cells; and Stage III was characterized by dense acellular collagen with scattered lymphoid follicles and occasional dystrophic calcification. Immunohistochemical studies in 17 cases highlighted large numbers of vimentin- and actin-positive spindle cells and capillary-like vessels in Stage I lesions, with fewer numbers of vimentin-positive, actin-negative spindle cells and vessels in Stage II lesions. Our findings suggest that "sclerosing mediastinitis" represents the final stage of an evolving, dynamic process with different morphologic appearances akin to abnormal wound healing. Thus, we propose the term fibroinflammatory lesion of the mediastinum to convey the true nature of the process.