18F FDG PET/CT demonstration of IVC and right atrial involvement in adrenocortical carcinoma
Raja Senthil . Bhagwant Rai Mittal · Raghava Kashyap . Anish Bhattacharya · Bishan Dass Radotra · Anil Bhansali
Received: 1 September 2011 / Accepted: 22 November 2011 /Published online: 17 December 2011 @ Japan Radiological Society 2011
Abstract Adrenocortical carcinoma is a rare and aggres- sive tumour. Inferior vena caval (IVC) involvement by the tumour thrombus is a rare phenomenon, and extension into the right atrium is even more rare. We describe a patient with Cushing’s syndrome for whom 18F-fluorodeoxyglucose (FDG) PET/CT showed FDG avid right adrenal mass with tumour extension to the IVC and right atrium.
Keywords Adrenocortical carcinoma ·
18F fluorodeoxyglucose PET/CT . Tumour thrombus . IVC invasion · Right atrial invasion
Introduction
Adrenocortical carcinoma (ACC) is a rare but aggressive tumour. It grows rapidly and tends to metastasize to the liver, lungs, kidneys, and bones. A few case reports have described fluorodeoxyglucose (FDG) uptake by an inferior vena caval (IVC) thrombus. However IVC involvement by the tumour thrombus is a rare phenomenon and extension into the right atrium is even more rare.
R. Senthil · B. R. Mittal ☒ Department of Nuclear Medicine and PET, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
R. Kashyap . A. Bhattacharya
e-mail: brmittal@yahoo.com
B. D. Radotra Department of Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
A. Bhansali
Department of Endocrinology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
Case report
A 40-year-old female patient presented with pain in the right hypochondrium for 4 months and features suggestive of Cushing’s syndrome of 1 year duration. On examination the patient was found to have a palpable mass in the right upper quadrant of the abdomen. Biochemical data were; 0800 hours cortisol, 1230 nmol/L; 2300 hours cortisol, 960 nmol/L; overnight dexamethasone suppression test, 1138 nmol/L; low-dose dexamethasone suppression test, 1059 nmol/L with ACTH <1.0 pg/ml. The patient was subjected to 18F FDG PET/CT scan. It showed intense FDG uptake (SUVmax 8.6) in a heterogeneously enhancing mass lesion measuring 10.2 × 11.2 × 9.2 cm, involving the right adrenal gland. Moderate FDG uptake (SUVmax 4.1) was also seen in a filling defect in the inferior vena cava (Fig. 1a, b). The uptake was seen extending upwards, reaching the right atrium with localisation of the tracer in the tumour thrombus (arrow) on CT (Fig. 1c). Histopa- thological examination of the tumour revealed an adrenal carcinoma with large areas of necrosis. The tumour cells were arranged in a typical endocrine pattern surrounded by fine capillary channels. Most of the neoplastic cells con- tained moderate to abundant eosinophilic cytoplasm and pleomorphic atypical nuclei (Fig. 1d). The morphology of the tumour thrombus was similar (Fig. 1e).
Discussion
Adrenocortical carcinoma is a rare and a highly malignant neoplasm [1]. It grows rapidly and tends to metastasize to the liver and lungs and to invade the kidney, renal veins, and IVC [2]. Tumours such as hypernephroma and hepatoma are well known to invade the IVC and right atrium [3].
A
B
C
D
E
However tumour thrombus in the IVC is a rare complication of ACC [3]. Cardiac involvement of adrenal carcinoma is even more rare; fewer than 25 cases have been described [4-9]. A few case reports have described FDG uptake by the IVC thrombus [3]. To the best of our knowledge, this is the first report describing 18F FDG PET/CT findings of cardiac involvement of ACC. The right adrenal vein courses directly into the vena cava which explains the potential for a right ACC to present with tumour thrombus in the IVC. Variation in the intensity of FDG uptake by the primary tumour and tumour thrombus is likely to be because of the low cellularity of the tumour thrombus compared with the
PET/CT (c) images. Histopathologically, most of the neoplastic cells in the adrenal carcinoma contained moderate to abundant eosinophilic cytoplasm and pleomorphic atypical nuclei (d). The morphology of the tumour thrombus was similar (e)
primary tumour, resulting in relatively lower FDG uptake by the thrombus. Important differential diagnosis of the FDG avid tumour thrombus is active benign thrombus, which may also have FDG avidity. One study has shown an SUVmax of 3.63 can be used to detect tumour thrombosis and is helpful in differentiating it from benign thrombus with sensitivity of 71.4% and specificity of 90% [10]. SUVmax of thrombus of 4.1 in this case helped differentiate the tumour thrombus from benign aetiology.
In conclusion, 18F-FDG PET/CT may be useful for investigation and combined detection of the primary tumour, local invasion, lymph nodal, IVC, and cardiac
involvement, and distant metastases in patients with ACCs by providing both functional and morphological information.
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