Endocrine Abstracts

Background: Adrenocortical carcinomas (ACC) are rare aggressive tumors occurring at a rate of less than two per million per year. Uncommonly, there can be intravascular extension into renal veins and inferior vena cava (IVC), with resultant poorer prognosis.

Clinical Case: A 26-year-old woman was referred for investigation of a two-month history of persistent left-sided abdominal pain - Computed tomography (CT) revealed a heterogeneous 12 cm left adrenal mass with thrombosis of left renal vein and IVC. On suspicion of ACC, biochemical tests showed combined hypercortisolism and hyperandrogenism (unsuppressed 1 mg dexamethasone overnight test 546 nmol/l [n<50], midnight salivary cortisol 364 ng/dl [n<100], DHEA 50.59 µmol/l [n<13.9], testosterone 12.4 nmol/l [n<1.9], ACTH <0.7 pmol/l [1.6-13.9]). Further imaging by ¹⁸F-FDG-PET-CT showed no distant metastasis. As the imaged thrombus was heterogeneous with high FDG avidity (Standard uptake volume SUV_max 19.6, compared to tumor SUV_max 23.1), it was determined as tumor thrombus instead of bland thrombus. Therefore, only prophylactic dose subcutaneous enoxaparin 40 mg daily was administered. Whilst awaiting curative resection, she developed lower limb deep vein thrombosis over the left common, internal and external iliac veins. Doppler ultrasound features suggested bland thrombus this time, with repeat CT revealing new pulmonary embolism. Anticoagulation was then escalated to therapeutic dose enoxaparin 1 mg/kg twice-daily until the day before surgery. The patient underwent enbloc left adrenalectomy, left nephrectomy, caval thrombus resection with mechanical thrombectomy of IVC and iliac thrombus. Intra-operatively, embolic protection discs were also deployed into the suprahepatic segment of IVC. Histopathology was consistent with ACC, with Ki67 index of 25%. The post-operative process was complicated by anterior abdominal wall hematoma. In view of ongoing need for anticoagulation, prophylactic embolisation of inferior epigastric and iliac arteries was carried out. 48h post-embolisation, therapeutic dose enoxaparin was restarted. However, 2 months later, she experienced hemorrhagic shock with hemoglobin level of 5.4 g/dl (n>11.5g/dl). Abdominopelvic CT then showed a large 14.5 cm hematoma, but with concomitant thrombosis of right renal vein, adjacent IVC, splenic infarct and spinal cord infarct.

Conclusion: This interesting case highlights the importance of recognising ACC as a hypercoagulable state-due to direct tumor invasion, tumor thrombi or secondary to hypercortisolism. Clinicians should be aware of this unique sequence of progression and associated complications. Recognition of venous invasion has clinical significance and management implications, highlighting the value of radiological modalities in differentiating tumor thrombus from bland thrombus. Timely implementation of anticoagulation is crucial and should be a tailored regimen considering individual risk factors and surgical plans.