18F-fluorodeoxyglucose positron emission tomography/computed tomography in the diagnosis of benign pulmonary lesions in sarcoidosis

Case Report: The immune architecture of immunotherapy-induced cutaneous sarcoidosis resembles peritumoral inflammation

Avelumab, is an anti-PD-L1 immune checkpoint inhibitor (ICI). Like other ICI, avelumab can cause immune-related adverse events. Although rare, sarcoidosis-like granulomatous reactions have been described in patients on anti-CTLA-4 and anti-PD-1 immunotherapy. Here we report a case of treatment emergent cutaneous sarcoidosis in a patient who received avelumab for metastatic colon cancer. A 56-year-old African American woman with metastatic colon cancer that had progressed after multiple lines of treatment, including other immunotherapy agents, was enrolled on a clinical trial with avelumab. While on treatment, the patient developed two skin lesions, and histopathological examination of both biopsies demonstrated chronic granulomatous inflammation in the dermis with multinucleated giant cells containing asteroid bodies, consistent with cutaneous sarcoidosis. Multiplex immunofluorescence revealed parallels between the immune architecture of the patient's cutaneous sarcoidal lesion and an excised tumor metastasis. Recognizing cutaneous sarcoidosis as a rare adverse effect of ICI immunotherapy is important because sarcoidal lesions can be mistaken for metastatic disease on clinical exam and medical imaging. We noticed similar immune composition of the sarcoidal granuloma and tumor microenvironment. However, further studies are needed to fully elucidate the mechanism of ICI associated sarcoidosis.

Development of a clinical prediction model for benign and malignant pulmonary nodules with a CTR ≥ 50% utilizing artificial intelligence-driven radiomics analysis

OBJECTIVE

In clinical practice, diagnosing the benignity and malignancy of solid-component-predominant pulmonary nodules is challenging, especially when 3D consolidation-to-tumor ratio (CTR) ≥ 50%, as malignant ones are more invasive. This study aims to develop and validate an AI-driven radiomics prediction model for such nodules to enhance diagnostic accuracy.

METHODS

Data of 2,591 pulmonary nodules from five medical centers (Zhengzhou People's Hospital, etc.) were collected. Applying exclusion criteria, 370 nodules (78 benign, 292 malignant) with 3D CTR ≥ 50% were selected and randomly split 7:3 into training and validation cohorts. Using R programming, Lasso regression with 10-fold cross-validation filtered features, followed by univariate and multivariate logistic regression to construct the model. Its efficacy was evaluated by ROC, DCA curves and calibration plots.

RESULTS

Lasso regression picked 18 non-zero coefficients from 108 features. Three significant factors-patient age, solid component volume and mean CT value-were identified. The logistic regression equation was formulated. In the training set, the ROC AUC was 0.721 (95%CI: 0.642-0.801); in the validation set, AUC was 0.757 (95%CI: 0.632-0.881), showing the model's stability and predictive ability.

CONCLUSION

The model has moderate accuracy in differentiating benign from malignant 3D CTR ≥ 50% nodules, holding clinical potential. Future efforts could explore more to improve its precision and value.

CLINICAL TRIAL NUMBER

Not applicable.

Pulmonary Granulomas and Mycobacterial Infection: Concordance between the Results of Special Stains Performed on Lung Tissue Sections and Tissue Cultures

Background: The most common cause of infectious pulmonary granulomas worldwide is Mycobacterium tuberculosis. The diagnosis is based on clinical presentation, histopathologic findings, detection of acid-fast bacilli (AFB) in tissue or sputum using special stains, and/or isolation of mycobacteria in cultures or via PCR-based methods. Different studies have shown that high levels of discrepancy exist between these diagnostic approaches in lung tissue specimens. Objective: To assess the degree of concordance between the results of special stains and cultures on lung tissue specimens in the diagnosis of mycobacterial infections. Methodology: Eighty-seven patients with a diagnosis of granulomas (necrotizing and non-necrotizing) on lung tissue specimens were identified. Cohen’s kappa was used to measure the general concordance between the results of the histopathological examination (special stains) and bacteriological tissue cultures. Results: With Kinyoun acid-fast stains, 8/48 (16.7%) cases were positive for AFB. With FITE stains, 10/57 (17.5%) cases were positive for AFB. There was strong agreement between Kinyoun acid-fast and FITE stains (Kappa = 0.806; p-value < 0.001). Tissue cultures were performed on 38/87 cases (43.7%), and 10/38 (26.3%) of the cultures were positive for mycobacteria. There was no concordance between Kinyoun acid-fast stains or FITE stains and tissue cultures results. Conclusion: Our observations represent an initial step in the process of reviewing the two methods used at our institution to diagnose mycobacterial infections on lung tissue specimens and highlight the need of incorporating more advanced diagnostic methods such as PCR to confirm mycobacterial infections and improve patient management. Importantly, species-level identification of mycobacteria is necessary to guide treatment.

Microvascular capillaroscopic abnormalities and occurrence of antinuclear autoantibodies in patients with sarcoidosis

We described nailfold videocapillaroscopy (NVC) findings and estimated the prevalence of serum anti-nuclear (ANA) and extractable nuclear antigen autoantibodies (ENA) in a cohort of sarcoidosis patients, comparing them with adequate healthy controls (HCs) and with primary Raynaud’s phenomenon patients (PRPs). NVC findings were also correlated with the occurrence of autoantibodies, current treatment, laboratory parameters, variables of lung function and whole-body imaging data. Twenty-six patients with sarcoidosis were assessed through NVC, laboratory parameters, pulmonary function tests, chest-X ray and 18- fluorodeoxyglucose positron emission tomography/computed tomography. The NVC parameters and ANA/ENA dosage were recorded also in 30 PRPs and 30 HCs. Sarcoidosis patients showed a higher rate of capillary dilations and nonspecific abnormalities and a lower mean capillary absolute number than PRPs and HCs (p < 0.01 for all comparisons). The prevalence of ANA positivity was higher in patients with sarcoidosis compared with PRPs and HCs (p < 0.02 for both), whereas ENA positivity was detected in one sarcoidosis patient (Ro52). Among sarcoidosis patients, the mean capillary absolute number negatively correlated with the C-reactive protein concentrations and was positively associated with the forced vital capacity percentage. Instead, a negative correlation was detected between serum ACE levels and the presence of capillary dilations (all p < 0.05). Our findings suggest a microvascular involvement in sarcoidosis whose investigation by NVC might be useful for the follow-up of patients displaying RP. Autoantibody positivity in sarcoidosis might suggest autoimmune implications in the disease or the production of autoantibodies reactive to tissue damage.

The diagnostic challenge of coexistent sarcoidosis and thyroid cancer - a retrospective study

BACKGROUND

Sarcoid lesions may mimic metastatic disease or recurrence in thyroid cancer (TC) patients as both diseases may affect the lungs and lymph nodes. We present the first study to systematically evaluate the clinical course of patients with (TC) after adjuvant radioactive iodine therapy (RIT) and concomitant sarcoidosis of the lung or the lymph nodes.

METHODS

We screened 3285 patients and retrospectively identified 16 patients with TC (11 papillary thyroid cancer (PTC), 3 follicular thyroid cancer (FTC), 1 oncocytic PTC, 1 oncocytic FTC) and coexisting sarcoidosis of the lung and/or the lymph nodes treated at our institute. All patients had undergone thyroidectomy and initial adjuvant RIT. Challenges in diagnosing and the management of these patients were evaluated during long term follow-up (median 4.9 years (0.8-15.0 years)).

RESULTS

Median age at first diagnosis of TC was 50.1 years (33.0-71.5 years) and of sarcoidosis 39.4 years (18.0-63.9 years). During follow-up, physicians were able to differentiate between SA and persistent or recurrent TC in 10 of 16 patients (63%). Diagnosis was complicated by initial negative thyroglobulin (Tg), positive Tg antibodies and non-specific imaging findings. Histopathology can reliably distinguish between SA and TC in patients with one suspicious lesion.

CONCLUSION

Physicians should be aware of the rare coexistence of sarcoidosis and TC. Lymphadenopathy and pulmonary lesions could be metastases, sarcoidosis or even a mix of both. Therefore, this rare patient group should receive a thorough work up including histopathological clarification and, if necessary, separately for each lesion.

[The application of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography in inflammation and infectious disease]

2-［ 18F］-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography ( 18F-FDG PET/CT) combining positron emission tomography with computed tomography is used to evaluate the body's glucose metabolic changes under different conditions. In addition to its established role in oncological imaging, 18F-FDG PET/CT has clinical utility in suspected inflammation and infection. The technique can identify the source of infection in a timely fashion ahead of morphological changes, map the extent and severity of inflammation, guide the site for tissue biopsy and assess therapy response. This article reviewed the use of 18F-FDG PET/CT in infection and inflammation, such as fever of unknown origin, sarcoidosis, vessel vasculitis, osteomyelitis, joint prosthesis or implant-related complications, human immunodeficiency virus-related infections, and other indications, such as inflammatory bowel disease, so as to provide reference for clinicians to select 18F-FDG PET/CT to help them in the diagnosis and treatment of inflammatory diseases.