Myelolipoma of the kidney: A review and update

Less than 10 cases of myelolipoma have been reported in the kidney as well as around the kidney. Myelolipoma involving the kidney, perirenal tissue or renal sinus may be discovered incidentally as part of investigation of other diseases; the disease may also present with loin pain, abdominal pain, abdominal bloating, haematuria or other non-specific symptoms. Radiological imaging tends to show a kidney mass with fat density attenuation on CT or MRI scan which tends to be non-contrast enhancing or it may show minimal enhancement. Diagnosis tends to be established by pathology finding of adipose tissue admixed with normal haematopoietic cells including all the three haematopoietic cell lineages (granulocytic, erythroid, as well as megakaryocytic). The disease may coexist with other diseases. The disease which exhibits a benign biological behaviour has been associated with various management options including conservative/surveillance approach, partial nephrectomy, radical nephrectomy or by complete excision of lesions surrounding the kidney whilst preserving the kidney. The lesion may derive its blood supply circumferentially from a peripheral leash of vessels and that there the lesion may not have a single arterial supply embolization may perhaps not be feasible in some cases. Differential diagnoses of the disease include: sarcomas of the kidney including liposarcoma, renal cell carcinoma, angiomyolipoma, and transitional cell carcinoma of the renal pelvis involving the renal parenchyma. The ensuing concluding summations would be made based upon the available literature on myelolipoma of the kidney: Myelolipoma is a rare benign disease and if it is diagnosed by undertaking radiological imaging guided biopsies/aspiration cytology a number of cases that a diagnosed in the future, it could be managed conservatively using the radiological imaging surveillance approach and the partial/radical nephrectomy option could be reserved for very large or symptomatic lesions.