CASE 10490 Published on 17.12.2012

Adrenocortical carcinoma: imaging findings

Section

Abdominal imaging

Case Type

Clinical Cases

Authors

Alexandra Ntorkou1, Athina C. Tsili1, Anna Gousia2, Maria I. Argyropoulou1

(1)Department of Clinical Radiology
(2)Department of Pathology

University Hospital of Ioannina,
Clinical Radiology,
Dept. Of Radiology;
Pl. Patgis 2
45332 Ioannina, Greece;
Email:a_tsili@yahoo.gr
Patient

56 years, female

Categories
Area of Interest Adrenals, Lung ; Imaging Technique Ultrasound, CT, MR, MR-Diffusion/Perfusion, RIS
Clinical History
A 56-year-old woman was referred for evaluation for adrenocorticotropic hormone (ACTH) – independent Cushing syndrome. Sonography revealed a large inhomogeneous solid mass in the area of the right adrenal gland. CT and MR imaging of the abdomen followed.
Imaging Findings
Abdominal sonography showed a large, heterogeneous mass of the right adrenal gland, invading the liver (Figure 1). Unenhanced CT examination demonstrated a large, mainly hypodense mass in the area of the right adrenal gland, with irregular margins (Figure 2). After contrast material administration, the neoplasm enhanced heterogeneously. Direct invasion of the right lobe of the liver was detected. Chest CT revealed a few small-sized pulmonary nodules (Figure 3), suggestive for the presence of haematogeneous metastases. At MR imaging the mass was inhomogeneous, mainly hypointense and hyperintense when compared to normal liver, on T1 and T2-weighted images, respectively, with mild, heterogeneous enhancement after gadolinium administration (Figure 4). DW images showed significant restricted diffusion by the neoplasm, confirming the diagnosis of malignancy (Figure 4). Pathologic analysis following surgery reported the presence of adrenocortical carcinoma (Figure 5). Liver invasion was confirmed both on surgery and histology..
Discussion
Background
Adrenocortical carcinoma (ACC) is a rare aggressive malignancy, accounting for only 0.05–0.2% of all cancers [1-4]. There is a bimodal age distribution with one peak incidence in infants and children younger than 5 years and a second peak in the fourth to fifth decades of life. ACCs are functional in approximately 60% of cases, more often in children (85%). In adults with functioning ACCs, 30% present with Cushing syndrome, 20% with virilization, and 10–20% with a combination of the two. The majority of ACCs (65% – 85%) in the adult population are non-functioning, presenting usually with abdominal pain or with symptoms related to mass effect.
Due to their location deep in the retroperitoneum, most ACCs are usually large at presentation (approximately 70% measure more than 6 cm in diameter) and in one third of cases present with metastatic disease at diagnosis, as it was in this case. Surgery is the standard mode of treatment, although not feasible for many patients. The overall prognosis of the disease is poor.

Imaging perspective

Typical CT findings include the presence of large, inhomogeneous suprarenal mass, displacing adjacent structures. Hyperdense internal areas are usually detected, consistent with the presence of haemorrhage. Areas of calcification are identified in approximately 30% of cases, usually centrally located. After contrast material administration, ACC enhances heterogeneously, mainly peripherally owing to the presence of central necrosis. Often, a thin rim of enhancing capsule is noted. At delayed-phase CT ACCs have a relative percentage washout of less than 40% [1-9].
At MR imaging, ACCs usually appear heterogeneous on both T1 and T2-weighted images, due to the presence of haemorrhage and/or necrosis. Lesion isointensity or slight hypointensity to normal liver parenchyma is seen on T1-weighted images, except in cases complicated with bleeding, detected with high signal intensity. ACCs often appear hyperintense to liver parenchyma on T2- weighted images, with a heterogeneous pattern of contrast enhancement, owing to the presence of areas of necrosis [1-10].
The presence of distant metastases is considered definite for the diagnosis of malignancy. Several imaging features increase the suspicion of ACC for an adrenal mass, including lesion size greater than 4 cm, irregular margins, presence of necrosis or haemorrhage, invasion into adjacent structures and venous extension [1]. Although, tumour size and heterogeneity are considered more reliable indicators for the diagnosis of malignancy, histologic examination is usually needed to reach a definite diagnosis.
Differential Diagnosis List
Adrenocortical carcinoma
Metastasis
Phaeochromocytoma
Large degenerated adrenal adenoma
Lymphoma
Ganglioneuroma
Infection
Neuroblastoma
Adrenal haemangioma
Final Diagnosis
Adrenocortical carcinoma
Case information
URL: https://www.eurorad.org/case/10490
DOI: 10.1594/EURORAD/CASE.10490
ISSN: 1563-4086