A comparison of the features of fluorine-18 fluorodeoxyglucose-positron emission tomography (FDG-PET) between IgG4-related disease with bilateral hilar lymphadenopathy and sarcoidosis

Value of 18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in the differential diagnosis of sarcoidosis and lung cancer with lymph node metastasis: a retrospective study

Background

Fluorine 18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) has been proven to be valuable in guiding the diagnosis and management of sarcoidosis. However, its differential value for sarcoidosis is unclear. The objective of this study was to explore the value of 18F-FDG PET/CT in differentiation sarcoidosis from lung cancer with lymph node metastasis.

Methods

A total of 361 consecutively diagnosed sarcoidosis patients and 1,944 consecutively diagnosed lung cancer patients at Shanghai Pulmonary Hospital were retrospectively reviewed. Among them, 85 patients diagnosed with sarcoidosis and 94 lung cancer patients with lymph node metastasis were enrolled. Demographic data and 18F-FDG PET/CT parameters were analyzed by the chi-square test or independent sample Student's t-test. Receiver operating characteristic (ROC) curves were generated to identify cut-off values. Multivariate logistic regression was performed to identify independent predictors of sarcoidosis on 18F-FDG PET/CT, and those with P<0.1 were included in a regression model using the forward log rank (LR) method to generate a ROC curve.

Results

The ratio of extrapulmonary lymph node involvement in sarcoidosis patients was significantly higher than that in lung cancer patients (64.7% vs. 29.8%, P<0.001). After adjusting for gender and age, extrapulmonary lymph node involvement [odds ratio (OR): 3.160; 95% confidence interval (CI): 1.105-9.035], maximum standardized uptake value (SUVmax) of mediastinum/hilar lymph nodes >13.86 (OR: 3.245; 95% CI: 1.045-10.083), and short axis of the corresponding lymph node >11.5 mm (OR: 5.470; 95% CI: 1.149-26.037) on 18F-FDG PET/CT were independent predictors of sarcoidosis, with a sensitivity and specificity of 77.5% and 69.3%, respectively. The area under the curve was 0.769.

Conclusions

18F-FDG PET/CT could be helpful to distinguish sarcoidosis from lung cancer patients with lymph node metastasis.

Diagnostic and Staging Value of Serum Angiotensin-Converting Enzyme in Sarcoidosis

Objective

To investigate the diagnostic and staging value of serum angiotensin-converting enzyme (sACE) in sarcoidosis.

Methods

Patients with suspected sarcoidosis treated in the Department of Pulmonary and Critical Care Medicine of the China-Japan Friendship Hospital from 2010 to 2020 were included. The data of sACE, erythrocyte sedimentation rate (ESR), complete blood count (CBC), lung function, bronchoalveolar lavage, and biopsy were collected. The differences between the sarcoidosis group and the nonsarcoidosis group and between different stages of sarcoidosis were compared. The receiver operating characteristic (ROC) curve analysis was used for the diagnostic test of sACE in sarcoidosis.

Results

A total of 84 cases with suspected sarcoidosis were included, among which 70 cases were confirmed to be sarcoidosis by biopsy. The mean value of sACE in sarcoidosis patients was 56.61 ± 30.80 U/L, which was significantly higher than that in nonsarcoidosis patients (28.07 ± 14.11 U/L, P = 0.001). The level of sACE in sarcoidosis patients with peripheral superficial lymph nodes and multiple system involvement was significantly higher than that in intrathoracic sarcoidosis patients (P = 0.009); the percentage of lymphocytes in bronchoalveolar lavage fluid (BALF) of sarcoidosis patients was 45.39 ± 22.87%, which was significantly higher than that of nonsarcoidosis patients (P < 0.001). There was no correlation between sACE and ESR (correlation coefficient = −0.167). According to ROC curve analysis, when sACE ≥ 44.0 U/L, the sensitivity of sarcoidosis diagnosis was 61.4%, the specificity was 92.9%, and the AUC was 0.819.

Conclusion

sACE has a good specificity in the diagnosis of sarcoidosis. sACE values in patients with sarcoidosis with systemic involvement were higher than those with simple intrathoracic sarcoidosis.

IgG4-related disease: a contemporary review

Background/aim

Immunoglobulin G4-related disease (IgG4-RD), is an immune-mediated fibroinflammatory condition, which may involve multiple organs and mostly presents with high serum IgG4 levels and specific histopathological characteristics. As IgG4-RD is a relatively new entity the etiology, prevalence and epidemiologic knowledge is quite limited. Although involvement of almost all anatomical regions has been reported, the most commonly affected regions are pancreas, lacrimal glands, salivary glands, retroperitoneum, orbita, lymph nodes, kidney and lungs. Diagnosis is made with combined evaluation of clinical, radiological and histopathological findings. Typical histopathological features include storiform fibrosis, dense lymphoplasmacytic infiltrates and obliterative phlebitis. Its course is typically marked by remission and relapsing attacks and it may lead to fibrosis, destructive lesions in tissues and organ failure unless promptly treated. In the treatment of IgG4-RD, many approaches including surgical resection of tissues, systemic glucocorticoids, steroid-sparing immunosuppressive drugs, and biological agents are employed. Although association is not clear, malignancies are frequently reported in IgG4-RD patients. Therefore, it is prudent to monitor patients for the symptoms of malignant diseases.

Conclusion

In this review, recent advances in clinico-pathological characteristics, diagnosis, and treatment of IgG4–RD are discussed.