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Adrenocortical carcinoma with inferior vena cava tumor thrombus found during surgery

Introduction The safety and efficacy of minimally invasive approaches for adrenocortical carcinoma with inferior vena cava tumor thrombus have not yet been established. We report a case of large adrenocortical carcinoma with inferior vena cava tumor thrombus found perioperatively which required conversion from a laparoscopic to an open procedure. Case presentation A 71‐year‐old woman with right‐side 10‐cm diameter adrenocortical carcinoma was scheduled for laparoscopic adrenalectomy. The operation was converted to open surgery, however, because inferior vena cava tumor thrombus, which was not detected by preoperative imaging modalities, was found during surgery. Conclusion In patients with large adrenocortical carcinoma, the possible presence of inferior vena cava thrombus should be considered when selecting surgical procedures.


Introduction
ACC is a rare neoplasm associated with poor prognosis. 1,2 IVC tumor thrombus has reported incidence of 10% in patients with ACC. 3 Open adrenalectomy has traditionally been recommended as the standard surgical procedure for ACC, but there is recent increase in the frequency of minimally-invasive approaches, such as laparoscopic and robotic surgery. 4 However, the safety and efficacy of these minimally invasive approaches for ACC with IVC tumor thrombus have not yet been established. We report a case of ACC that required conversion from laparoscopic to open procedure due to perioperatively detected IVC tumor thrombus, with discussion of the optimal choice of surgical methods for ACC.

Case presentation
A 71-year-old woman was presented with pollakiuria. Physical examination revealed increased density of eyebrows and pubic hair, and pitting edema in her legs. In laboratory analysis, serum cortisol was 18.3 lg/dL, plasma adrenocorticotrophic hormone was 1.0 pg/ mL, and plasma dehydroepiandrosterone sulfate was 4452 lg/dL. Endocrinologic investigation revealed disappearance of circadian change of serum cortisol and the loss of suppressibility of serum cortisol by dexamethasone, suggesting Cushing's syndrome. Enhanced abdominal CT scan showed a 10-cm right-side adrenal mass with heterogeneous enhancement (Fig. 1a-d). Although the mass compressed the IVC, CT images did not detect IVC tumor thrombus. MRI showed the mass was a hypointense lesion on T1-weighted image and hyperintense lesion on T2-weighted image (Fig. 1e,f). MRI images also failed to show the IVC tumor thrombus. On 131 I-adosterol scintigraphy, the right adrenal gland was associated with low uptake. From these observations, there was preoperative suspicion of ACC with Cushing's syndrome and the clinical stage was determined as cT2N0M0.
Laparoscopic adrenalectomy was initially attempted, although after soft tissues around right adrenal vein was removed, tumor thrombus was found in the vein (Fig. 2). Ultrasonography revealed that tumor thrombus slightly extended to the IVC. The operation was therefore converted from laparoscopic to open approach by making an inverted L-shaped skin incision which connected three laparoscopic ports on the right upper abdomen. After clamping the IVC at the head side and the tail side of the right adrenal vein, we performed open adrenalectomy and removal of IVC tumor thrombus. The defect of IVC was continuously sutured using 5-0 prolene (Ethicon, Somerville, NJ, USA). Histological examination revealed that the mass was an adrenal cortical neoplasm with extension to the IVC, the Weiss score was 7 and the Ki-67 proliferation index was high, more than 60% (Fig. 3). The patient was therefore diagnosed with ACC with the pathological stage pT4N0M0. Although she underwent adjuvant mitotane treatment, positron emission tomography scan showed recurrence in the liver 4 months postoperatively.

Discussion
ACC is associated with poor prognosis, and the 5-year survival rate in patients with ACC is reported to be 16-35%. 5 between open and laparoscopic surgery in patients with ACC <10 cm without local invasion; perioperative outcomes in the laparoscopic group were better than those in open surgery group without difference between the groups in oncological outcomes. 9 However, the efficacy and safety of laparoscopic surgery for ACC ≥10 cm have not been specifically reported. Moreover, ACC with IVC thrombus tend to be large in size, as shown in Table 1. The presence of IVC thrombus is an important factor when selecting surgical methods, so IVC thrombus should ideally be detected preoperatively, especially in patients with large right-sided ACC. However, preoperative diagnosis of the presence of IVC tumor thrombus is difficult by using conventional imaging techniques including abdominal CT scan because the IVC can be compressed by large tumors, like in the present case. 10 The usefulness of intracaval endovascular ultrasonography or enhanced MRI for preoperative detection of IVC thrombus has been previously reported, 10,11 but further investigation is required owing to limited evidence.
The efficacy and safety of laparoscopic or robot assisted surgery have been recently reported for advanced renal cell carcinoma with IVC tumor thrombus. 12,13 To our knowledge, however, there are no reports about the outcomes of these minimally-invasive surgical techniques for ACC with IVC thrombus. The wall of the adrenal vein is thinner and weaker than that of the renal vein. Tumor thrombus of the ACC has been reported to have higher risk of pulmonary infarction than that of renal cell carcinoma because it is gelatinous and vulnerable. 14 Considering these backgrounds, there must be careful consideration of the application of laparoscopic or robotic surgery to the ACC with IVC thrombus.
We therefore propose the following surgical methods for ACC: when local invasion of tumors is suspected from preoperative CT images, open procedure should be selected. When local invasion is not suspected, although laparoscopic surgery should be initially selected for tumors <10 cm, IVC thrombus should be re-evaluated using intraoperative ultrasonography. If thrombus is detected during surgery, the surgical procedure should be converted to open procedure. For tumors ≥10 cm, preoperative intracaval endovascular ultrasonography or enhanced MRI should be used to evaluate the presence of tumor thrombus. If IVC tumor thrombus is observed, open procedure should be selected. If IVC tumor thrombus is not detected, we recommend performing laparoscopic procedure and reevaluating the presence of tumor thrombus during surgery with intraoperative ultrasonography in the same way as for tumors <10 cm.

Conclusion
In patients with large ACC, especially >10 cm, surgical procedures should be performed with consideration of potential for IVC thrombus.