The utility of a touch preparation in the diagnosis of fluctuant subcutaneous fat necrosis of the newborn.

Subcutaneous fat necrosis of the newborn (SFNN) is an uncommon self-limiting panniculitis. Lesions may be fluctuant and spontaneously drain. Here we report a technique to rapidly confirm the diagnosis of SFNN when fluctuance exists via a touch preparation that demonstrates the characteristic histologic features of this condition. The material can be collected by fine needle aspirate, from draining fluctuant lesions, or if biopsy if performed.