Case of paraneoplastic pemphigus associated with retroperitoneal diffuse large B‐cell lymphoma and fatal bronchiolitis obliterans‐like lung disease

trauma. Smetana et al. postulated that the lipogranulomatous reaction results from the breakdown of endogenous lipids following trauma. Lee et al. reported a lipogranuloma originated from endogenous fat degeneration after a traumatic process. At the time of the accident, damaged fat tissues were destructed and degenerated. Then, lipogranuloma could have developed at the site of the trauma. In addition, there is the possibility of lymphatic migration of degenerated fat from the surgical site. Microdroplets of damaged and liquefied fat may undergo phagocytosis and be transported to other sites through lymphatics. Fat necrosis is induced by various causes, including foreign body injection, trauma, vascular insufficiency, infections and connective tissue diseases. In this case, the patient had obvious trauma history. In addition, the patient did not have a history of local injections into the skin lesions and any symptoms or signs of vascular insufficiency of the legs. In our case, we consider that posttraumatic lipogranuloma developed as a result of a combination of factors associated with trauma, including the endogenous fat degeneration and petroleum-based dressing products. Physicians should recognize the possibility of lipogranulomatous reactions associated with a traumatic process.