10. Adrenal myelolipoma – a case report

Adrenal myelolipoma is a rare benign tumour of the adrenal gland. The tumour was first described in 1905 by Gierke 1 who described a lesion of the adrenal gland composed of fat and myeloid elements. The first use of the term myelolipoma was by Oberling in 1929. 2 The tumour is usually unilateral and non-secreting, although bilateral tumours have been reported in the literature. Adrenal my-elolipomas are usually incidental findings either at autopsy or as a result of radiological investigation performed for other indications. The precise incidence is unknown, but is estimated to be between 0.06% and 0.25% based on autopsy studies. 3–5 The pathogenesis is unclear and various aetiologies have been proposed including bone marrow embolisation, embryonic primitive mesenchymal cells, dysregulation of haematopoietic cell apoptosis, and adrenal cortical metaplasia in response to stimuli. Histologically, the tumours demonstrate normal trilineage haematopoeisis and cellular morphology. Megakaryocytes are present in increased numbers compared to normal bone marrow. Early myeloid precursors are not commonly seen. 5 We report the case of a 58-year-old woman with an adrenal myelolipoma containing prominent lymphoid follicles resembling splenic white pulp.