Introduction: Adrenal myelolipoma is a rare benign tumour composed of mature adipose tissue and haematopoietic elements developed within the adrenal gland, usually unilateral, asymptomatic, and non-functional. Their real incidence is unknown.
Case report: A 56 year-old female was admitted to our surgery department for abdominal distension and the presence of a large palpable tumour in the right abdomen discovered during an abdominal ultrasonographic check-up for an incisional hernia, and with no noticeable symptoms. Patients medical history: a 3rd stage systemic arterial hypertension, insulin requiring type 2 diabetes mellitus, hysterectomy with adnexectomy for a cervical cancer. The abdominal ultrasound examination showed a large hyperechogenic tumour, heterogenic, located in the right flank and hypochondriac region.
The contrast enhanced computed tomography scan revealed a large retroperitoneal tumour (25×17×21 cm) well delimitated with a heterogenic structure (liquid and non-iodophile lipid densities, and central calcifications). The mass was in contact with the right hepatic lobe, inferior vena cava, ascendant and transverse colon, and, posteriorly, with the diaphragm. The CT showed also a 74 mm incisional hernia with incarcerated small bowel.
Biochemical evaluation: serum potassium=4.2 mmol/l, serum cortisol=204.8 nmol/l; after a 1-mg overnight dexamethasone suppression test serum cortisol=22.1 nmol/l.
Taking into account the tumoral mass dimensions, surgical resection was decided. Because of the medial incisional hernia, a medial subxifoid-pubic incision was performed.
Histopathological evaluation: macroscopic examination revealed a large thin encapsulated tumour, firm in consistence, with a heteromorphic aspect with calcifications in section; the microscopic examination: adrenal cortex, adipose tissue, and multiple (extramedullary) haematopoiesis sites adrenal myelolipoma. The patient had a good postoperative evolution.
Conclusion: The incidentally detected tumoral mass in the clinical condition of the patient challenged to differentiate an adrenal adenoma (functional or not) from a retroperitoneal lipoma/liposarcoma, or metastasis. A particularity of this myelolipoma was the tumour size (approx. 8.925 cm3).