Computed tomography and magnetic resonance images of adrenocortical oncocytoma cases

Abstract

We present two cases of adrenocortical oncocytomas that were well-delineated on multi-detector computed tomography and magnetic resonance imaging. The images showed a well-enhanced large mass with multiple stippled calcifications in a 10-yr-old girl who was consulted due to precocious puberty. A well-enhanced solid mass with necrotic components was incidentally noticed in a 54-yr-old man. These lesions were resected and diagnosed as adrenocortical oncocytomas through immunohistochemical studies and electron microscopy. Adrenocortical oncocytomas are rare disease entities, therefore, we report these interesting, rare adrenocortical oncocytomas here with radiologic findings, and discuss differential diagnosis.

Keywords: Adrenal Glands; Computed Tomography; Magnetic Resonance Imaging; Neoplasms-Oncocytoma.

Fig. 1

Adrenocortical oncocytoma in a 10-yr-old girl (Case 1), abdominal multi-detector CT findings. (A) A well-circumscribed, oval-shaped mass in the left adrenal gland with stippled calcifications on a precontrast scan. (B) Thoroughly heterogeneous enhancement during the 1-min delayed axial scan. (C) On a coronal reconstructed image of B. (D) Enhancement washout in the 15-min delayed scan.

Fig. 2

Adrenocortical oncocytoma in a 10-yr-old girl (Case 1), gross and microscopic findings. (A) The tumor was approximately 6×4 cm, well-encapsulated and dark brown in color, and it consisted of multiple small hemorrhagic vascular lakes with old blood. (B, C) A microscopic examination revealed that the neoplasm was comprised of polygonal cells with abundant eosinophilic cells and granular cytoplasm. A nuclear cellular atypia with enlarged nuclei was identified (B: ×200 HPF, C: ×400 HPF, H&E). (D) By electron microscopy, electron dense inclusions, as well as closely packed mitochondria with Golgi complexes, were found (×400 HFP).

Fig. 3

Adrenocortical oncocytoma in a 54-yr-old man (Case 2), MR images. The mass primarily demonstrates hypointensity on in-phase T1WI MR imaging (A) without a definite signal drop on the opposed-phase T1WI MR imaging (B), with a central hemorrhagic necrotic component. On T2WI MR imaging (C, axial; D, coronal), this mass is primarily of slightly high signal intensity with a central hyperintense portion.

Fig. 4

Adrenocortical oncocytoma in a 54-yr-old man (Case 2), contrast-enhanced MR images. (A) Precontrast (B-D) Thoroughly heterogeneous enhancement of a solid tumoral portion at the 1-min (B), peak enhancement at 3-min (C), and slight enhancement washout at the 5-min delayed phases (D). Intratumoral hemorrhagic necrosis is visualized as a constantly non-enhancing portion.

Fig. 5

Adrenocortical oncocytoma in a 54-yr-old man (Case 2), gross and microscopic findings. (A, B) The tumor was an oval-shaped soft mass that was encapsulated by a thin fibrous capsule and a multifocal brownish hemorrhage with a focal cystic change. (C) The tumor was composed of epithelial cells with abundant acidophilic cytoplasm, nuclear pleomorphism, and a diffuse growth pattern, as observed using a light microscope. (D) By electron microscopy, the oncocytic cytoplasm was filled with a large number of mitochondria, as well as some lysosomes, Golgi bodies, small lipid particles, and glycogen particles.