Retroperitoneal panniculitis is a rare, benign and nonspecific inflammatory disease that affects the retroperitoneal adipose tissue. The specific cause of the disease is unknown. The diagnosis is evoked by computed tomography and is rarely confirmed by biopsies. Treatment is based on a few selected immunosuppressive drugs. Surgical resection is sometimes attempted for complicated forms, although the surgical approach is often limited. We report a case of a 22-year-old man diagnosed with retroperitoneal panniculitis complicated by a paralytic ileus and mimicking an acute abdomen. A self-limiting course of disease was obtained by adopting a conservative approach.