Erythema-Multiforme-Like Eruption Recurring in Ultraviolet-Exposed Skin

181 Encapsulated fat necrosis, also named ‘nodular cystic fat necrosis’, ‘mobile encapsulated lipoma’ or ‘posttraumatic degeneration and herniation’, was first described in 1975 by SchmidtHermes and Loskant [4] . It is characterized by solitary or multiple, subcutaneous nodules, mostly located on the lower extremity and consisting of degenerated or necrotic fat tissue encapsulated by thin to thick fibrous tissue. The exact causes remain unclear; however, trauma and subsequent interruption of blood supply are speculated to play a major role [5] . Histopathology shows a fibrous capsule with degenerated or necrotic fat tissue in between, sometimes accompanied by inflammation and calcification. The synopsis of clinical aspect, ultrasound, aspirated tissue and histopathology confirmed the diagnosis of encapsulated fat necrosis in our patient. It seems that the injected PPC-containing substance led to fat necrosis with the subsequent formation of surrounding fibrosis [5] . The edema, typically induced by injection lipolysis, may also play an additional role, probably by reducing the local blood supply due to pressure. In our patient, further treatments with PPC were rejected due to the complication. Both physician and patient did not observe sufficient fat reduction after the performed 2 injections. To the best of our knowledge, our patient is the first case to present encapsulated fat necrosis after injection lipolysis for the reduction of localized fat accumulations. We assume that encapsulated fat necrosis has to be seen as a possible complication of the nonsurgical procedure described above. Considering the supposed mechanism of action of PPC and the frequency of the procedure, we assume that encapsulated fat necrosis is underreported.