Staged surgical management of follicular thyroid carcinoma with extensive thrombus reaching up to right atrium – A case report

Highlights • Follicular thyroid carcinoma with venous tumor thrombus extending to right atrium.• Two staged surgery avoids operative complexity, with better post operative outcome.• Initially cardio-thoracic part done to eliminate the risk of pulmonary embolism.• In second stage thyroid tumor resection with tumor thrombus extraction was done.• 12 months recurrence free survival was observed.


Introduction
Thyroid cancers constitute 1%-5% of all malignancies worldwide and are increasing in incidence globally [1]. Differentiated thyroid cancer consists of papillary and follicular carcinoma, which is having favorable prognosis. Although follicular thyroid cancers may show microscopic vascular invasion, macroscopic venous tumor thrombus extending from cervical veins to mediastinal great veins and reaching to the right atrium (RA) is extremely rare [1][2][3][4][5]. Here we report a case of follicular thyroid carcinoma with tumor thrombus formation in the internal jugular vein & extending into the Superior Vena Cava (SVC) and RA; which is treated with radical intent in two stage surgery. The patient was treated successfully by a collaborative head-neck and cardiothoracic surgeons team. This case has been reported in line with the SCARE criteria [6]

Case report
A 52-year-old female was referred to us with diffuse thyroid swelling since 8 months. The patient was not having dysphagia, dyspnoea or hoarseness of voice, with no significant medical illness in the past. Pertinent physical examination revealed a large lobulated mass on anterior aspect of the neck with separate fusiform swelling laterally in the right side of neck; initially it appeared to be a nodal metastasis. Her pulse was 88 beats/min, blood pressure was 136/78 mmHg and normal heart sound with no audible murmur. Fine-needle aspiration cytological examination revealed    through the inferior thyroid vein into the innominate vein. The same thrombus was extending down to reach SVC and RA (Fig. 1A, C). Furthermore on metastatic work-up there was no evidence of pulmonary embolism or distant metastasis.
2D echo-cardiography for cardiac evaluation showed tumor thrombus formation as mentioned above. Surprisingly rests of the cardiac functions were normal.

Operative findings
Only few cases of thyroid carcinoma with an extensive tumor thrombus in the atrium have been reported in the literature. Yamagami et al. described a single staged approach in a similar case of thyroid carcinoma with RA thrombus [8]. We anticipated complex surgical procedure, since thrombus was adherent to the anterior wall of RA. We planned surgery in two sequential stages by a team of head-neck and cardiovascular surgeons: Stage 1, Median sternotomy for removal of RA & SVC Thrombus. Stage 2, Total thyroidectomy and extensive thrombectomy of neck veins.
Stage 1:-To avoid the sudden death due to pulmonary embolism, it was decided to resect the intracardiac extension of the tumor before going to definitive neck surgery. Median sternotomy was performed and pericardium was opened. Patient was given heparin sodium 2 mg/kg before handling great vessels. Aortic cannulation was performed for cardio-pulmonary bypass purpose.
Inferior vena cava (IVC) and right innominate vein was also cannulated with minimal manipulation of RA. Cardiopulmonary bypass was established under normothermia with IVC drain and ascending aortic perfusion. Patient's body temperature was reduced to 22 o C and heart beating was arrested with cardioplegia. Cardiopulmonary bypass was stopped and Total circulatory arrest achieved. Right atriotomy was performed (Fig. 2) and tumor adhesions were separated from RA wall. SVC venotomy was done by separate incision and tumor thrombus along with its extensions was delivered out through right atriotomy (Fig. 3B). Right IJV & right inferior thyroid vein openings into innominate vein were closed using intraluminal purse string sutures. SVC and RA incisions were closed separately using running sutures (Fig. 3A). Patient was slowly re-warmed to normal body temperature i.e. 37 • C and cardiopulmonary bypass was started. Total circulatory arrest time was 22 min, patient recovered without any complications.
Stage 2: Neck surgery for thyroid cancer was planned after complete recovery from cardio-thoracic procedure. U-shaped neck incision was given and skin flap was raised. There was diffuse thyroid swelling with distinctly seen separate lateral neck swelling on right side, which was thrombus in the IJV (Fig. 4). Prophylactic Bilateral neck and central compartment dissection was done; which was followed by dissection for total thyroidectomy. Right IJV was opened with proximal and distal control and tumor thrombus extraction was done (Fig. 5A). While dissecting Inferior Thyroid  vein we found 2 nd tumor thrombus, so again inferior thyroid venotomy performed and tumor thrombus was extracted through the venotomy (Fig. 5B). Neck veins ostia (IJV and Inferior thyroid vein) draining into right innominate were obliterated by using purse string suture at the time of previous cardiothoracic part, so there was no fear of accidental migration of tumor thrombus into the SVC.
Total thyroidectomy specimen was removed in continuity with IJV and inferior thyroid vein thrombus. Final pathological diagnosis was follicular thyroid carcinoma with extensive intravenous tumor thrombosis. (T4b, N0, M0, stage IVA).

Postoperative course & follow-up
Cardiothoracic surgery part was done first followed by 4 days recovery in intensive care unit. Neck surgery was performed after 10 days of first surgery. Patient recovered without any complication and discharged from the hospital 7 days after the second surgery, total hospital stay was around 17 days.
Patient followed up closely, and after 1 month, radio-Iodine isotope-scan followed by Radioactive-iodine-131 (RAI-131) ablation with 100 mCi dose was done. Patient was monitored with serum thyroglobulin levels every third month. Patient is asymptomatic with no evidence of recurrence on RAI scan at the end of 12 months follow-up.

Discussion
Differentiated carcinoma of thyroid with haematogenus spread extending into the IJV is well reported entity [9], but spread to SVC and RA is very rare. Tumor thrombus in major vessels is reported in other malignant diseases like renal cell carcinoma, uterine carcino-sarcoma, Wilm's tumor, testicular tumor, adrenal cortical carcinoma, lymphoma, pancreatic cancer, osteosarcoma and Ewings sarcoma [10]. Incidence of tumor thrombus of thyroid cancer is very rare and has been reported to be 0.2-3.8% [11][12][13]. In the past, Surgery for a thyroid carcinoma with extensive tumor thrombus in the internal jugular vein was first reported by Thompson et al. [2] in 1978. To the best of our Knowledge only a few case reports that describe management of thyroid carcinoma with an extensive tumor thrombus in IJV, SVC and RA have been reported in literature [8]. Proposed mechanism is, tumor invades into IJV and the high velocity flow in the cervical vein prevents the invasion of endothelium of the great vessels. This will not allow the tumor to lateralize and invade into the vessel wall [7]. Intravascular tumor extension usually propagates with intraluminal invasion by malignant cells and deposition of fibrin, leading to continued growth into the innominate vein, SVC and RA [14].
Invasion of the great vessels by thyroid carcinoma is usually associated with early relapse and poor prognosis [15], but if tumor in blood vessels is resected without residual tumor, a better prognosis is possible [1,2,11,13]. Literature also mentions survival up to 3 years after aggressive surgical resection in similar cases [16].
Similar cases receiving only palliative treatment due to difficult surgical approach resulted in poor outcome [3,17]. There are no standard guidelines available in the literature to manage this condition [18], though there are anecdotal case reports of successful surgical treatment of this condition. Yamagami et al. [8] reported a case of successful surgical resection of thyroid cancer with extensive tumor thrombus in the RA. Intraluminal extension is not a contraindication for aggressive surgical treatment in differentiated thyroid cancers due to the relatively good prognosis. Other important reasons to strongly consider surgical treatment are to avoid airway occlusion, fatal pulmonary embolism and RA obstruction [19].
Treatment strategies should be discussed among multidisciplinary team [20]. In the literature two ways of thrombus extraction were discussed: First, by resection of mediastinal great vessels along with tumor thrombus (with or without reconstruction). Second, to do venotomy for removal of tumor thrombus with subsequent closure of venotomy. Nakano et al. [1] reported that inhibition of thyroid stimulating hormone and RAI as an adjuvant treatment is effective to improve survival.

Conclusion
Tumor thrombus usually occurs in the advanced stage of the differentiated thyroid cancer and implies that such tumors behavior is aggressive with poor prognosis. Preoperative evaluation by appropriate imaging and collaborative multi-modality approach for treatment plan is recommended. In absence of distant metastasis, median sternotomy for tumor thrombus removal and radical surgery in the neck for thyroid cancer would be the treatment of choice. Surgical treatment is definitely useful to avoid sudden fatal tumor embolism and also to improve survival. In our case, staged surgical approach was found to be safe and effective. It avoided operative complexity and perioperative morbidity with better post operative outcome.

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Ethical approval
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Consent
Informed consent from the patient have been taken before sending for publication.

Author contribution
1. Dr. Prashant Lad-Cntributed to operation, follow up and writing manuscript 2. Dr. Jateendar Kumar-Cntributed to operation, follow up and writing manuscript 3. Dr. Jagadish Sarvadnya -Cntributed to operation, follow up and writing manuscript 4. Dr. Abhijith Powar -Cntributed to operation, follow up and writing manuscript

Registration of research studies
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Provenance and peer review
Not commissioned, externally peer-reviewed.

Declaration of Competing Interest
I have no conflicts of interest to disclose concerning this case report.