|Year : 2019 | Volume
| Issue : 4 | Page : 356-358
Submental nodal metastasis in papillary carcinoma of the thyroid
Jeyashanth Riju, Shaji Thomas
Department of Head and Neck Surgical Oncology, Regional Cancer Centre, Trivandrum, Kerala, India
|Date of Web Publication||11-Oct-2019|
Department of Head and Neck Surgical Oncology, Regional Cancer Centre, Trivandrum, Kerala
Source of Support: None, Conflict of Interest: None
Papillary carcinoma of thyroid (PCT) commonly shows metastasis to central and lateral cervical compartment neck nodes. Submental nodes are rarely involved by PCT. Thus, its management is not clear. We report two young men who presented with submental nodal metastasis from PCT. Both underwent total thyroidectomy with central compartment neck dissection and modified radical neck dissection (MRND). Probable factors which might influence submental nodal metastasis are analyzed. We conclude that physicians should be aware of the possibility of submental nodal metastasis from PCT. A selective approach for neck dissection can be an alternative to MRND, reducing the morbidity in management of such cases.
Keywords: Metastasis, neck dissection, papillary carcinoma thyroid, submental node, thyroid
|How to cite this article:|
Riju J, Thomas S. Submental nodal metastasis in papillary carcinoma of the thyroid. Indian J Cancer 2019;56:356-8
| » Introduction|| |
Papillary carcinoma thyroid (PCT) is the most common thyroid malignancy. It has a high chance of cervical nodal metastasis, with various literatures quoting between 30% and 90%. Unlike other head and neck malignancies, the prognosis of PCT is good, despite nodal metastasis. Lymphatic spread in PCT has a pattern, which is as follows: from the thyroid to level VI, then to the lateral compartment of the neck, and finally to posterolateral compartment of the neck. Hence, in PCT with nodal metastasis, the treatment mandates removal of thyroid, central compartment neck dissection along with lateral neck dissection or posterolateral neck dissection, as per the metastatic nodal status., But when level I is involved, there is no recommendation regarding the type of neck dissection to be done. Moreover, factors influencing level Ia involvement have not been studied.
Submental nodal involvement is rare; so, it can be easily missed in clinical examination or routine ultrasonography (USG) unless specifically looked for. Nodal involvement does not significantly alter the prognosis in thyroid malignancy. However, missing a significant node might alter adjuvant treatment plans. Questions still remain regarding (1) pattern of lymphatic spread to level Ia, (2) factors that influence level Ia nodal involvement, (3) extent of neck dissection needed when level Ia node is involved, and (4) distant metastasis/aggressiveness with level IA involvement.
We present two cases of PCT with submental nodal involvement and discuss relevant clinical, radiological, surgical, and pathological features.
| » Case History|| |
A 23 year old man presented with complaints of swelling in front of the neck for 6 months. Fine-needle aspiration cytology (FNAC) from the swelling and thyroid showed PCT with lymph node metastasis. Contrast-enhanced computerized tomography (CECT) of neck and thorax was done which showed 6.5 × 3.8 × 3.8 cm mass in the right lobe of the thyroid with calcific foci and an 8 × 8 mm nodule in the left lobe. Bilateral level I–IV and level VI neck nodes were involved. There was no evidence of pulmonary metastasis. Clinical examination showed 6 × 3 cm thyroid swelling in the right side and clinically significant neck node in level Ia [Figure 1] and bilateral level II. Indirect laryngoscopy was normal.
He underwent total thyroidectomy, central compartment neck dissection, right modified radical neck dissection, and left posterolateral neck dissection. About 2.5 × 2 cm black node was noted in level Ia during the procedure.
Histopathological examination showed multifocal papillary thyroid carcinoma involving both thyroid lobes and isthmus with capsular invasion. Delphian node, measuring 0.6 × 0.3 cm, showed metastatic papillary carcinoma. Pyramidal lobe measuring 1 × 0.2 cm showed normal thyroid parenchyma. Level Ia showed metastatic papillary carcinoma with extracapsular tumor invasion. Harvested level Ib showed three nodes, all showing reactive changes. Of the 39 lymphnodes harvested in other stations 28 showed metastatic papillary carcinoma including positive central compartment nodes.
A 30 year old man presented with complaints of swelling below the chin for 2 months. FNAC from the swelling was reported as metastasis from papillary carcinoma. CECT showed hypodense lesion in the right lobe of the thyroid, which was otherwise normal in size. Significant nodes were noted in level Ia and bilateral levels II–IV. Clinical examination showed 1 × 1 cm thyroid swelling in the right side and clinically significant neck node in level Ia and bilateral level II/III. No evidence of pulmonary metastasis was found. Indirect laryngoscopy was normal [Figure 2].
He underwent total thyroidectomy, central compartment neck dissection, right modified radical neck dissection, and left posterolateral neck dissection. About 3 × 2 cm black node was noted in level Ia during the procedure.
Histopathological examination showed 3 × 2.5 × 2 cm papillary carcinoma thyroid involving right thyroid lobe and isthmus with capsular invasion. Delphian node was not detected. Pyramidal lobe measured 2 × 1 cm and showed normal thyroid parenchyma. Level Ia showed metastatic papillary carcinoma with extracapsular tumor invasion. Harvested level IB showed three nodes, all showing reactive changes. Of the 30 lymph nodes harvested, 16 showed metastatic papillary carcinoma including positive central compartment nodes.
| » Discussion|| |
PCT is well known for its lymph node metastasis. Hence, careful planning with aid of imaging is required prior to surgery. 191 patients underwent total thyroidectomy for thyroid malignancy in 2017, at our institution, which included neck dissection in 66 patients (35%) for nodal disease. Only two patients had submental nodal involvement. There are many differential diagnoses for submental swelling, namely, thyroid ectopia, thyroglossal duct cyst, lymphadenopathy, lipoma, dermoid cyst, and neoplasm. Thus, unless suspected and properly evaluated, the diagnosis might be missed, leading to misadventure in patient management.
With regard to our cases, both were young men who had tumors involving isthmus of the thyroid with capsular invasion and central compartment nodal metastasis. Delphian node was involved in one patient and could not be retrieved in other. In both the patients, level Ib did not reveal any metastatic node, although CT scan showed enlargement. Both patients had nodes with extracapsular extension. There was no evidence of pulmonary metastasis in both cases.
The pattern of lymphatic spread in thyroid malignancy is a well-established fact. Central compartment neck nodes are the first to be involved, followed by lateral compartment neck nodes and then posterior compartment neck nodes. The surgery for lateral neck node metastasis also involves central compartment and lateral compartment node clearance.,,, But this is not the same for submental nodal metastasis. The evaluation of our cases suggests that probable pattern of spread to level Ia node might be from high-risk tumor involving isthmus of thyroid spreading to the Delphian node and further extension to level Ia. This is supported by the fact that none of the ipsilateral level Ib node has metastasis. Thus, it rules out nodal metastasis from the lateral compartment. The detection rate of Delphian node is 26.3% in a study of a large population of 1000 patients with thyroid malignancy; this might be the reason we did not find Delphian node in case 2.
One of our patients presented with a complaint of submental swelling, the other was diagnosed to have a submental node on clinical examination. Submental node is an unlikely area of thyroid nodal metastasis. Clinical examination can detect nodal involvement only in about 15–30% of patients. Nodal enlargement in such a location, due to metastasis, is prone to escape the clinician's notice. Shi et al. in their study had 2 patients with level I involvement out of 165 patients.
FNAC will usually establish the diagnosis as in our case. Further diagnostic imaging can be carried out using USG, iodine scans, CT, magnetic resonance imaging, and positron emission tomography/CT. USG examination is the most widely used investigation to evaluate thyroid and nodal status, but this may miss level I nodal involvement unless specifically looked for. We evaluated our case with CECT of neck and thorax to rule out pulmonary metastasis.
During surgery, level Ia node was noted as a black-colored node. This is due to hemosiderin deposition. A study by Crist et al. had demonstrated BRAF mutation frequently in patients with blackish node compared to nonblack node. BRAF mutation is associated with clinically aggressive tumor. Both of our cases showed thyroid disease with capsular invasion and extranodal extension, which indicates thyroid disease with level Ia nodal involvement, might have aggressive tumor biology.
No consensus is available regarding the extent of neck dissection in PCT with submental nodal involvement. However, most surgeons prefer doing an ipsilateral modified radical neck dissection clearing level I to V. When level Ia is involved, we propose central compartment clearance and level Ia clearance along with total thyroidectomy. Level Ib dissection can be avoided unless clinically or radiologically indicated. This will avoid the morbidity of level Ib dissection, mainly marginal mandibular nerve injury. Lateral compartment neck dissection is advocated when indicated.
| » Conclusion|| |
PCT being the most common thyroid malignancy with frequent nodal metastasis, nodal dissection still remains a controversy. Level Ia might be involved due to spread from Delphian node, from a high-risk tumor. Level Ib dissection can be avoided unless clinically or radiologically indicated.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]