Clinicopathological Characteristics of Four Cases of Adrenal Myelolipomas: A Rare Surgical Entity

Abstract

Myelolipomas are unusual benign tumors or tumor-like lesions, composed of hematopoietic cells and mature adipose tissue. They usually are asymptomatic and behave as non-functioning, unilateral, small adrenal tumors often found incidentally on imaging studies. We report the clinicopathological characteristics of four cases of adrenal myelolipomas treated in our hospital, worth to mention because of their rarity and their significant size. Myelolipomas were first described by Gierke in 1905, and the term myelolipoma was coined by Oberling in 1929. The adrenal gland is the most common site, but myelolipomas are also rarely present in extra-adrenal sites, including the pelvis, mediastinum, retroperitoneum, and paravertebral region, as an isolated soft tissue mass. These tumors account for 2.6% of the primary adrenal masses with equal sex distribution and in our reviewed material of a decade they constitute about 5% in a series of surgically treated adrenals for various neoplastic processes of the adrenals. Although usually small in size, in our series a remarkable large size of the tumors examined was observed, ranging from 7 - 15 cm. Adrenal myelolipoma is often an "incidentaloma", since its diagnosis is frequently based on autoptic findings or made during surgical interventions and imaging procedures performed for other purposes, as happened in our cases.

Keywords: Adrenal gland; Adrenalectomy; Myelolipoma.

Figure 1

Histological section of adrenal gland showing both normal adrenal tissue and myelolipoma (hematoxylin-eosin × 120).

Figure 2

Histological section of myelolipoma indicating haemopoetic elements and lipocytes (hematoxylin-eosin × 240).