Background: The role of imaging in the management of Rosai-Dorfman disease (RDD), a rare non-Langerhans cell histiocytosis, is not clearly defined. We present an analysis of FDG PET/CT findings obtained for initial disease characterization, follow-up evaluation, and treatment planning for this disease. Methods: From an institutional pathology database (2001–2018), we identified RDD patients who underwent FDG PET/CT scans either as part of clinical care or when done as part of clinical trials. For all scans, sites of abnormal FDG uptake were assessed, and SUVmax was measured. Comparison of PET/CT findings was made with anatomic (CT/MRI-based) imaging, where available. Instances of changing treatment based on PET/CT were recorded. Results: We reviewed 109 FDG PET/CT scans in 27 patients with RDD. Five of 27 patients had only nodal/cutaneous disease, whereas 22 patients had extranodal disease, most commonly in bone (n = 9) and central nervous system (n = 7). PET/CT identified sites of active disease in 24 of 27 patients. All identified bone and extraskeletal lesions, except for a brain lesion in 1 patient, were FDG-avid. In 6 of 20 patients (30%) with available prior CT or MRI, PET/CT demonstrated additional RDD lesions (bones: n = 5, pleura: n = 1) that were not apparent on anatomic imaging; 3 of these lesions were outside the CT field of view, and 3 were not recognized on CT. Overall, 13 of 109 PET/CT scans led to a change in management, affecting 41% (11/27) of patients. Conclusion: FDG PET/CT was valuable in defining disease extent and optimizing treatment strategy in patients with RDD.

• The United States food and drug administration has recently granted approval to the targeted ¹⁷⁷Lu-PSMA-617 therapy in prostate cancer patients. • Salivary glands show high PSMA-ligand uptake and are prone to radiation damage secondary to accumulation of ¹⁷⁷Lu-PSMA-617. • Salivary gland scintigraphy is a noninvasive highly reproducible technique, useful for objective and quantitative assessment of salivary flow and function of parotid and submandibular glands and can help detect early changes post ¹⁷⁷Lu-PSMA-617 therapy.

Ketamine is a noncompetitive antagonist of the N-methyl-D-aspartate (NMDA) receptor which also interacts with various other receptors that account for its myriad actions. Originally approved as a general anesthetic, it is being explored to be repurposed for numerous other indications such as depressive disorders, suicidal ideation, substance-use disorders, anxiety disorders, chronic pain, refractory status epilepticus, and bronchial asthma exacerbations. Numerous trials are ongoing for the same. The nasal spray of esketamine, a more potent S (+) enantiomer of ketamine, has been approved by the United States Food and Drug Administration (USFDA) for treatment-resistant depression along with the oral antidepressants. However, there are concerns about its safety on long term use, given its psychedelic effects and potential abuse. In this review, we discuss repurposing ketamine for potential therapeutic use and about the safety concerns related to ketamine and esketamine.

Background Cutaneous squamous cell carcinoma (cSCC) is the second most common skin malignancy. Computed tomography (CT) and/or MRI are commonly used for staging, however, the role of fluorine-18-fluorodeoxyglucose (¹⁸F-FDG)-PET is not clearly established. In this study, we evaluated ¹⁸F-FDG-PET/CT imaging for initial staging of cSCC. Patients and methods ¹⁸F-FDG-PET/CT scans performed in patients with newly diagnosed cSCC were reviewed retrospectively. Images were visually assessed for lesions and ¹⁸F-FDG uptake [standardized uptake value (SUV)] in primary and secondary sites was measured. Suspected lesions on ¹⁸F-FDG-PET/CT were correlated with histopathology when available, follow-up imaging or clinical data in others. Results Twenty-three cSCC patients who underwent ¹⁸F-FDG-PET/CT at diagnosis were evaluated. Primary sites were in head/neck (n=21), chest (n=1), and foot (n=1). All patients had ¹⁸F-FDG-positive scans with a total of 51 ¹⁸F-FDG-positive lesions. All primary lesions (n=24) were ¹⁸F-FDG-positive (SUV: 2.3–22.8; mean 10.2), and additional 27 ¹⁸F-FDG-positive lesions, including 21 nodes, four cutaneous, one osseous and one lung lesion, were noted in 13 patients. Mean size of ¹⁸F-FDG-positive nodes was 0.9 cm (range: 0.4–2.5 cm), predominantly clinically impalpable. Pathology was available for 40/51 lesions; 31 sites positive for malignancy. SUV (mean±SD) was 9.2±6.2 for malignant and 2.7±1.2 for benign lesions. Sensitivity, positive predictive value, and accuracy of ¹⁸F-FDG-PET/CT scan were 100, 77.5, and 77.5%, respectively. ¹⁸F-FDG detected seven additional lesions in three patients, compared to CT/MRI. Overall, staging ¹⁸F-FDG-PET/CT detected nine prior unknown lesions in five patients that were proven metastatic disease by histopathology or follow-up; ¹⁸F-FDG-PET/CT modified management in 5/23 (21.7%) patients. Conclusion ¹⁸F-FDG-PET/CT has high sensitivity in the detection of cSCC lesions, including small cutaneous and nodal disease, and has a potential role in initial staging and management.