Pediatric sarcoidosis is rare with an estimated incidence of 0.2 per 100, 000 per year. The mean age of onset is 13–15 years, but presentations may vary with age [
1,
2]. The hallmark finding of sarcoidosis are the presence of non-caseating epithelioid granulomas, which are believed to be an antigen-driven cell-mediated immune response involving CD4+ T cells that eventually differentiate into Type 1 T helper (Th1) cells which then secrete IL-2 and IFN-γ, supporting macrophage TNF-α production, promoting the cellular immune response [
3,
4]. The recruited and organized immune cell collections include activated macrophages that have been shown to produce 1-α hydroxylase which converts cholecalciferol (25-OH Vitamin D) to calcitriol (1, 25-dihydroxy Vitamin D) [
5]. Calcitriol then increases intestinal calcium absorption and bone resorption leading to hypercalcemia and/or hypercalciuria, known to be frequent features of the disease particularly in those with high granuloma burden. Epithelioid cells of the granulomata produce angiotensin converting enzyme (ACE), a controversial biomarker of sarcoidosis that is often elevated, but lacks diagnostic specificity and sensitivity [
6,
7]. Thus, some laboratory findings could be suggestive of granuloma presence and activity, but pursuit must be taken to find tissue for histopathologic confirmation and diagnosis. In a recent review of 101 adult cases of calcitriol-mediated hypercalcemia, approximately half were eventually diagnosed with sarcoidosis [
8]. Overall, granulomata are an infrequent finding on skeletal muscle biopsies [
9]. When isolated, sarcoidosis and idiopathic granulomatous myositis are the two most frequent causes, respectively. Symptomatic presentations of sarcoid myopathy have multiple phenotypes including nodular and atrophic forms and are more often from chronic disease [
10]. The frequency of asymptomatic granulomatous myositis in sarcoidosis has been estimated between 50 and 80 % and occurs more often in early stages of the disease [
11]. Our case underscores the importance of considering sarcoidosis or granulomatous myositis in patients who present with hypercalcemia of unclear etiology and reinforces the need for tissue diagnosis and exclusion of other causes. MRI showed excellent utility in detecting granulomatous myositis in patients without typical myositis features and anti-TNF monoclonal antibody therapy was efficacious in our refractory case.