A case report of extra-adrenal retroperitoneal myelolipoma.

Myelolipoma is a benign tumor composed of mature adipose tissue and hematopoietic elements, typically found in the bone marrow. It mainly occurs in the adrenal gland, with only over 50 cases of extrarenal myelolipoma reported in literature, and extrarenal renal myelolipoma occurring in the posterior abdominal cavity is particularly rare. Currently, there are only 6 reported cases abroad. We report a case of extrarenal retroperitoneal medullary lipoma treated after abdominal pain, which was misdiagnosed as well differentiated retroperitoneal liposarcoma before surgery. The patient was successfully discharged after surgical resection. This paper provides a detailed summary of the clinical presentation, imaging features, diagnosis, and management course of this case, aiming to offer diagnostic and therapeutic insights for clinicians and future research.