A 2-week-old neonate was brought to the emergency department for evaluation of a “lump” on the back. The lesion was first noted shortly after birth, but had been expanding since then. The delivery process had been long and complicated.



 This history and lesional morphology are virtually pathognomonic for subcutaneous fat necrosis. Firm, erythematous nodules develop on cheeks, buttock, back, or thighs during the first 2 weeks of life, almost always following a stormy, often hypoxic delivery.



 The skin lesion need not be treated; it will resolve spontaneously.



 This rather banal appearing process may be complicated by life-threatening hypercalcemia. Serum calcium levels need monitoring and the neonate maintained in a well-hydrated state.

Skin Diseases

This lump on the back of a neonate was noted shortly after birth and had been expanding. What is it?