Images of the month 1: Trident sign and neurosarcoidosis

Typical trident sign and cardiac involvement in a patient suspected to Sarcoidosis despite negative whole-body FDG-PET: a case report

BACKGROUND

Sarcoidosis is a systemic inflammatory disease histologically defined by the non-caseation granulomas formation in different organs, most commonly lungs, liver, skin, gastrointestinal system, eyes, neurologic and cardiac system CASE PRESENTATION: We report the case of a 42-year-old Gilaks woman who presented with myelopathy with characteristic MRI finding called trident sign. By finding this view in axial spinal Magnetic Resonance Imaging (MRI) imaging, a systemic evaluation was performed on the patient, which led to the diagnosis of cardiac involvement in Sarcoidosis with the specific appearance of this disease in cardiac MRI despite the negative Fluorodeoxyglucose (FDG)-positron emission tomography (PET) scan.

CONCLUSIONS

Sometimes characteristic findings such as the trident sign prompt the physician to high suspicion and wide evaluation of the patient to reveal important organ involvement that changes the treatment decision and saves the patient.

Relevance of Medullary Vein Sign in Neurosarcoidosis

Background: Central nervous system involvement is uncommon in patients with sarcoidosis. It remains a diagnostic challenge for clinicians, as there is a broad differential diagnosis that matches the presenting neurological signs. Often, the imaging findings also overlap with other disease entities. One understudied finding in patients with neurosarcoidosis is the presence of medullary vein engorgement on SWI imaging, termed the “medullary vein sign”, which has been postulated to be a specific sign for neurosarcoidosis. This study aims to provide an understanding of the diagnostic potential of the medullary vein sign. Methods: Thirty-two patients who presented with neurologic signs concerning for possible neurosarcoidosis were analyzed retrospectively for the presence of the medullary vein sign. Results: Out of these cases, 7 cases of definitive neurosarcoidosis cases were found based on other imaging signs, biopsy and CSF analysis; the remaining were classified into groups as possible (16), probable (5) and (4) cases of other infectious meningoencephalitis including 2 cases of autoimmune encephalitis. Seven patients among all of these cases were found to have the medullary vein sign on imaging, with five cases with confirmed and two cases from possible neurosarcoidosis. The sensitivity of the medullary vein sign in this study was 71.4%, and the specificity was 92.3%. Discussion: The benefits of improving diagnostic criteria for neurosarcoidosis include more rapid diagnosis leading to more prompt treatment, less exposure to potentially harmful antibiotics or antifungals, and less long-term neurological effects. Our results support that the medullary vein sign will potentially fill in the diagnostic gaps that have challenged the timely diagnosis of neurosarcoidosis. Conclusions: Our findings support that the medullary vein sign has a high specificity and should be included in the diagnostic criteria for neurosarcoidosis.