A 6-day-old term girl was brought to the hospital due to a lump appearing in the back two days ago, without trauma history or fever. Physical examination revealed a violaceous indurated subcutaneous nodule. Laboratory investigation revealed normal calcium levels. Ultrasound showed increased thickness and echogenicity of the subcutaneous tissue and lipomatous edema. A diagnosis of subcutaneous fat necrosis was made. The lesion regressed gradually, without complications.

Figure 1: Subcutaneous nodule in the back.

Figure 2: Subcutaneous nodule in regression.

Subcutaneous fat necrosis of the newborn is rare and affects fullterm newborns in the first weeks of life often following a traumatic delivery [1,2]. It is a panniculitis and presents mostly on the cheeks, buttocks, arms, thighs or back [1,3]. Hypercalcaemia, which may appear until six months after the skin lesion, is the most severe complication [4]. The majority of lesions resolve spontaneously and prognosis is generally good except for the cases of hypercalcaemia [1,4]. Accurate diagnosis allows early detection and treatment of complications.