Subcutaneous fat necrosis of newborn: report of two cases.

Subcutaneous fat necrosis of newborn (SFNN) is an uncommon disorder. Submandibular lesion and tissue eosinophilia have not been documented. Two patients with unusual location and unusual pathological findings are reported. Both patients were giant babies, delivered by vaginal route spontaneously with birth injury. Asymptomatic subcutaneous nodules were found over the submandibular area at the ages of 16 and 6 days respectively. Nodules disappeared spontaneously at the age of one month in the first, and two months in the second patient. Histopathological examination of the nodules revealed features typical for SFNN: lobular panniculitis with fat necrosis and radiating needle-shaped clefts within multinucleated histiocytes. In addition to mononuclear cells, eosinophils were abundant in the infiltrate. Because of these unusual features, it is suggested that SFNN should be considered in the differential diagnosis of submandibular subcutaneous nodule in the newborn, clinically; and of lobular panniculitis with eosinophilia, histologically.