Characteristics of patients with a diagnosis of sarcoidosis: a comparison of the 2006 and 2015 versions of diagnostic criteria for sarcoidosis in Japan

Granuloma, vasculitis, and demyelination in sarcoid neuropathy

BACKGROUND

Despite the suggestion that direct compression by granuloma and ischemia resulting from vasculitis can cause nerve fiber damage, the mechanisms underlying sarcoid neuropathy have not yet been fully clarified.

METHODS

We examined the clinicopathological features of sarcoid neuropathy by focusing on electrophysiological and histopathological findings of sural nerve biopsy specimens. We included 18 patients with sarcoid neuropathy who had non-caseating epithelioid cell granuloma in their sural nerve biopsy specimens.

RESULTS

Although electrophysiological findings suggestive of axonal neuropathy were observed, particularly in the lower limbs, all but three patients showed ≥1 abnormalities in nerve conduction velocity or distal motor latency. Additionally, a conduction block was observed in 11 of the 16 patients for whom waveforms were assessed; five of them fulfilled motor nerve conduction criteria strongly supportive of demyelination as defined in the European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) guideline for chronic inflammatory demyelinating polyneuropathy (CIDP). In most patients, sural nerve biopsy specimens revealed a mild to moderate degree of myelinated fiber loss. Fibrinoid necrosis was observed in one patient, and electron microscopy analysis revealed demyelinated axons close to granulomas in six patients.

CONCLUSIONS

Patients with sarcoid neuropathy may meet the EAN/PNS electrophysiological criteria for CIDP due to the frequent presence of conduction blocks. Based on our results, in addition to the ischemic damage resulting from granulomatous inflammation, demyelination may play an important role in the mechanism underlying sarcoid neuropathy.

Myocardial tissue changes detected by cardiac MRI in a patient with suspected systemic sarcoidosis

BACKGROUND

The role of cardiac magnetic resonance imaging in the early management of chronic cardiac inflammatory conditions is growing. Our case enlightens the benefit of quantitative mapping in the monitoring and treatment guidance in systemic sarcoidosis.

CASE PRESENTATION

We report about a 29-year-old man with an ongoing dyspnea and bihilar lymphadenopathy, suggesting sarcoidosis. Cardiac magnetic resonance showed high mapping values, but no scarring. In follow-ups, cardiac remodeling was noted; cardioprotective treatment normalized cardiac function and mapping markers. Definitive diagnosis was achieved in extracardiac lymphatic tissue during a relapse.

CONCLUSION

This case shows the role that mapping markers can play in the detection and treatment at early stage of systemic sarcoidosis.

The differential diagnosis of IgG4-related disease based on machine learning

INTRODUCTION

To eliminate the disparity and maldistribution of physicians and medical specialty services, the development of diagnostic support for rare diseases using artificial intelligence is being promoted. Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a rare disorder often requiring special knowledge and experience to diagnose. In this study, we investigated the possibility of differential diagnosis of IgG4-RD based on basic patient characteristics and blood test findings using machine learning.

METHODS

Six hundred and two patients with IgG4-RD and 204 patients with non-IgG4-RD that needed to be differentiated who visited the participating institutions were included in the study. Ten percent of the subjects were randomly excluded as a validation sample. Among the remaining cases, 80% were used as training samples, and the remaining 20% were used as test samples. Finally, validation was performed on the validation sample. The analysis was performed using a decision tree and a random forest model. Furthermore, a comparison was made between conditions with and without the serum IgG4 concentration. Accuracy was evaluated using the area under the receiver-operating characteristic (AUROC) curve.

RESULTS

In diagnosing IgG4-RD, the AUROC curve values of the decision tree and the random forest method were 0.906 and 0.974, respectively, when serum IgG4 levels were included in the analysis. Excluding serum IgG4 levels, the AUROC curve value of the analysis by the random forest method was 0.925.

CONCLUSION

Based on machine learning in a multicenter collaboration, with or without serum IgG4 data, basic patient characteristics and blood test findings alone were sufficient to differentiate IgG4-RD from non-IgG4-RD.

COVID-19 mRNA Vaccine-Associated Uveitis Leading to Diagnosis of Sarcoidosis: Case Report and Review of Literature

A 34-year-old Japanese person with male gender identity who had been taking intramuscular injection of methyltestosterone depot for 11 years after bilateral mastectomy noticed blurred vision 5 days after the second vaccination for COVID-19 (Tozinameran; Pfizer-BioNTech) in the interval of 3 weeks following the first vaccination. The patient was diagnosed as granulomatous iritis with mutton-fat keratic precipitates and small iris nodules at the pupillary margin in the right eye and began to have 0.1% betamethasone eye drops with good response. The patient, however, continued to have fever and malaise and showed a high level of serum soluble interleukin-2 receptor (sIL-2R) even 4 weeks after the second vaccination. Computed tomographic scan disclosed mediastinal and bilateral hilar small lymphadenopathy together with limited granular lesion in the right lung. Gallium-67 scintigraphy demonstrated high uptake not only in mediastinal and hilar lymph nodes but also in bilateral parotid glands. Right parotid gland biopsy revealed noncaseating granulomas and proved pathological diagnosis of sarcoidosis. The systemic symptoms were relieved by oral prednisolone 20 mg daily. Even though the causal relationship remains undetermined, this case is unique at the point that vaccine-associated uveitis led to the detection of pulmonary lesions and lymphadenopathy, resulting in clinical and pathological diagnosis of sarcoidosis. In literature review, 3 patients showed sarcoidosis-like diseases after COVID-19 vaccination: 2 patients were diagnosed clinically as Lofgren syndrome with acute onset of erythema nodosum and ankle swelling, with or without mediastinal and hilar lymphadenopathy, whereas 1 patient with mediastinal lymphadenopathy but no uveitis was diagnosed pathologically by biopsy as sarcoidosis.

Advances in Diagnostic Imaging for Cardiac Sarcoidosis

Sarcoidosis is a systemic granulomatous disease of unknown etiology, and its clinical presentation depends on the affected organ. Cardiac sarcoidosis (CS) is one of the leading causes of death among patients with sarcoidosis. The clinical manifestations of CS are heterogeneous, and range from asymptomatic to life-threatening arrhythmias and progressive heart failure due to the extent and location of granulomatous inflammation in the myocardium. Advances in imaging techniques have played a pivotal role in the evaluation of CS because histological diagnoses obtained by myocardial biopsy tend to have lower sensitivity. The diagnosis of CS is challenging, and several approaches, notably those using positron emission tomography and cardiac magnetic resonance imaging (MRI), have been reported. Delayed-enhanced computed tomography (CT) may also be used for diagnosing CS in patients with MRI-incompatible devices and allows acceptable evaluation of myocardial hyperenhancement in such patients. This article reviews the advances in imaging techniques for the evaluation of CS.