Post-COVID-19-Associated Asymptomatic Sarcoidosis with Hypercalcemia and Renal Dysfunction: A Case Report and Literature Review.

BACKGROUND Sarcoidosis is a multisystem granulomatous disease of unknown etiology that often presents with nonspecific symptoms and lacks a definitive diagnostic test. Diagnosis can be particularly challenging in atypical cases without hallmark features such as bilateral hilar lymphadenopathy or cutaneous lesions. The recent literature suggests that post-COVID-19 immune dysregulation may act as a novel trigger for sarcoidosis. CASE REPORT We present the case of a 60-year-old Black woman with hypertension, osteoarthritis, and a recent coronavirus disease 2019 (COVID-19) infection complicated by persistent anosmia. Routine laboratory testing revealed hypercalcemia, renal insufficiency, and anemia. Despite discontinuing over-the-counter supplements, her hypercalcemia persisted, although she remained otherwise asymptomatic. Diagnostic workup showed normal 25-hydroxy vitamin D, suppressed parathyroid hormone (PTH) levels, and elevated 1,25-dihydroxy vitamin D. Imaging revealed nonspecific pulmonary nodules without hilar lymphadenopathy. Biopsy of a supraclavicular lymph node demonstrated non-caseating granulomas, establishing the diagnosis of sarcoidosis. Treatment with oral prednisone led to improvement of biochemical abnormalities and radiographic findings. CONCLUSIONS This case underscores the diagnostic challenges of sarcoidosis in the absence of classic pulmonary features and highlights the importance of recognizing hypercalcemia and elevated 1,25-dihydroxy vitamin D as key diagnostic clues. Notably, to the best of our knowledge, no prior reports have described asymptomatic sarcoidosis in the post-COVID-19 setting, making this case a unique contribution to the emerging literature. However, as this is a single-patient observation, causality cannot be inferred, and larger studies are needed to explore this potential association.