Bone Abstracts

Background: Subcutaneous fat necrosis (SCFN) of the newborn is an uncommon condition most commonly seen in term infants who have experienced perinatal stress presenting as nodules or plaques on the face, back or upper extremities. The associated complication of hypercalcemia is thought to be secondary to elevated 1,25-OH vitamin D from increased expression of 1-alpha hydroxylase from inflammatory granulomatous cells. However the natural history of SCFN, associated hypercalcemia and its possible long term effects has not been well described. Clinical observation at the Hospital for Sick Children (HSC) suggests that ongoing hypercalcemia, albeit less severe than at presentation, persists for a number of months beyond the resolution of palpable nodules. Given this, our objectives were to evaluate the natural history of SCFN, associated hypercalcemia and serial laboratory values.

Cases: We reviewed the cases of 8 children diagnosed with SCFN and associated hypercalcemia followed in the HSC Calcium Clinic; 7 of 8 followed to resolution. Of the 8 children; 5 presented following hypoxic ischemic encephalopathy and cooling, 1 following traumatic vacuum assisted delivery and 2 were found to have incidental skin lesions. On average hypercalcemia was detected at 1 month of age, with a peak calcium value of 3.42±0.56 mmol/L. The children were typically seen in follow up every 4 months, and after initial hospital treatment, were managed on a restricted calcium intake. Based on serial clinical exams, palpable subcutaneous nodules resolved on average after 10.5±7.6 months. The resolution of hypercalcemia lagged behind, with a normalization of serum calcium occurring at 25.3±9.5 months. Four of the children developed nephrocalcinosis These children had the highest peak serum calcium values at diagnosis of the group.

Discussion: Given hypercalcemia can persist well beyond the clinical resolution of nodules, there is risk that these children may be discharged from follow-up prematurely with possible persistent urinary calcium excretion and risk of nephrocalcinosis. A closer look at other, possibly predictive factors, including 1,25 vitamin D levels and duration of dietary restriction may be useful in guiding our future monitoring and management of these patients.

Disclosure: The authors declared no competing interests.