nasopharyngeal cancer is an uncommon head and neck cancer ( hnc ) in most parts of the world . in india , a higher incidence is seen in the northeastern states , particularly nagaland , manipur , and mizoram . it is a chemo- and radio - sensitive tumor and has a high propensity for lymphatic spread and distant metastasis . radiotherapy ( rt ) with concurrent chemotherapy is the mainstay in the management of advanced disease . the most common sites of involvement are bone ( 70%80% ) followed by liver ( 30% ) , lungs ( 18% ) , and distant lymph nodes ( axillary , mediastinal , pelvic , and inguinal ) . about 98% of them thyroid parenchymal metastasis is an uncommon site of metastasis with an incidence ranging from 0.5% to 24% . the most common primary sites are kidney , lungs , breast , and colorectum with hncs being a minority ( 0.02% ) . we were only able to identify eight reported cases in the literature of intrathyroidal parenchymal metastasis from nasopharyngeal cancer . in this case report , we present a case of nasopharyngeal carcinoma ( the second primary in a previously treated case of oropharyngeal carcinoma ) with thyroid metastasis managed with surgery and adjuvant reirradiation with concurrent chemotherapy . a 61-year - old male , a resident of mizoram , presented with complaints of pain while swallowing . indirect laryngoscopy showed submucosal disease in the left lateral pharyngeal wall in the region of the tonsil . computed tomography ( ct ) scan showed heterogeneous - enhancing mass in the left parapharyngeal space measuring 2.4 cm  2.3 cm  5 cm with multiple ipsilateral levels ii and iii lymph nodes [ figure 1a ] . he was treated with 6 mv photons , using conventional bilateral portals to face and neck with shrinking fields to a dose of 70 gy/35 fractions with six cycles of concurrent weekly cisplatin . postradiation clinical examination showed no evidence of disease , and the patient was on regular follow - up . ( a ) a sagittal and coronal computed tomography scan showing a left parapharyngeal mass in the region of the tonsil . ( b ) axial sections of computed tomography scan showing a soft tissue mass in the right nasopharynx . after a disease - free interval ( dfi ) of 5 years , the patient presented with a swelling in the right axillary region measuring 2 cm  2 cm . a positron emission tomography - ct ( pet - ct ) was done which showed a localized soft tissue mass in the right nasopharynx , along with a bulky right axillary nodal mass of 4.8 cm  3.4 cm with no evidence of disease in the oropharynx and neck [ figure 1b ] . the patient was managed as a second primary in the nasopharynx , ct2n0m1 stage iv . in view of the good general condition , long dfi , and the axillary node being the only site of metastasis , the patient was planned for radical treatment . he was treated with 9-field intensity - modulated rt ( imrt ) with 6 mv photons to face and neck at a dose of 60 gy in 30 fractions along with six cycles of concurrent weekly cisplatin . the right axillary region was treated with anteroposterior ( ap / pa ) portals at a dose of 50 gy in 25 fractions with 6 mv photons . at follow - up , 3-month posttreatment , pet - ct showed complete response with no uptake anywhere in the body , and nasopharyngoscopy revealed no abnormality . after a dfi of 1 year and 3 months , a routine follow - up pet - ct revealed a 9 mm nodule in the right lobe of thyroid ( standardized uptake value [ suv ] : 6.73 ) and a pretracheal node ( suv : 4.53 ) [ figure 2a and b ] . ultrasonography ( usg ) of the neck showed hypoechoic lesion in the right lobe of thyroid measuring 1.4 cm  1.3 cm . a usg - guided fnac showed poorly differentiated carcinoma cells consistent with metastasis from the nasopharynx [ figure 3 ] . since this was the only site of the disease , he underwent right hemithyroidectomy with right levels ii intraoperative findings were suggestive of tumor around the recurrent laryngeal nerve and in the tracheoesophageal groove . a 2 cm  2 cm node at pretracheal region in superior mediastinum was also excised . positron emission tomography - computed tomography on a routine follow - up showing a nodule in the right lobe of thyroid ( a ) and a prevascular node ( b ) . the tumor cells were oval to spindle with scanty cytoplasm , vesicular nuclei , and prominent nucleoli ( pap stain ; [ a ] 40 and [ b ] 200 ) . histopathology showed a grayish - white nodule measuring 2.1 cm  1.5 cm  1.5 cm located in the right lobe of thyroid abutting the inked margin . serial sections showed a focus of metastasis of undifferentiated carcinoma , nasopharyngeal type with a heavy lymphoplasmacytic infiltrate . the extrathyroidal extension was noted . the tumor cells were immunopositive for high - molecular weight cytokeratin and revealed moderate - to - strong diffuse nuclear positivity for epstein - barr - encoded rna / in situ hybridization . both pretracheal nodes showed metastatic carcinoma with perinodal extension [ figure 4a  d ] . ( a - d ) photomicrograph showing metastatic deposits of undifferentiated nasopharyngeal carcinoma in thyroid with interspersed lymphoid cells ( a and b ; h and e , 100 and  200 ) . the tumor cells were immunopositive for high molecular weight cytokeratin ( c ; dab : 100 ) and revealed moderate - to - strong diffuse nuclear positivity for epstein - barr - encoded rna / in situ hybridization ( d ; dab ; 100 ) . although the patient had received radical rt on two previous occasions , the lower neck had received only the elective dose of 50 gy , and it was felt that the tumor bed and levels vi and vii were at a high risk of recurrence in the presence of positive margins . he received a total dose of 60 gy in 30 fractions to a small ct - planned volume including the thyroid bed , adjacent esophagus , and central compartment of neck including the superior mediastinum ( levels vi and vii ) . treatment was delivered by a 9-field imrt plan with 6 mv photons along with concurrent weekly nimotuzumab over 42 days with no gaps in treatment [ figure 5a and b ] . he had nociceptive pain over the anterior aspect of the neck associated with dysphagia and odynophagia . he was referred to palliative care services for pain and symptom management . achieving good locoregional control and palliative care interventions improved his pain , symptoms , and quality of life ( qol ) for many months . axial slice of the planning computed tomography cuts showing adequate coverage of tumor bed ( a ) and pretracheal node in superior mediastinum ( b ) . hncs have a high propensity for local recurrence and second primary cancers ( spcs ) in view of large area of mucosa exposed to carcinogens . the common sites of elevated risk of spc are other sites within the upper aerodigestive tract . a second hnc is the most common spc associated with oropharynx . with a better understanding of the biology of cancers and therapeutic advances leading to improved survival , the incidence of spc has increased . patients with metachronous spc from early - stage hnc have a better survival with curative treatment . presentation of nasopharynx as spc in oropharyngeal carcinoma is very uncommon , about 0.01% of all cases . in this case , given the long time interval between the two cancers , good performance status of the patient , and the radiosensitivity of the spc tumor , this patient was considered for reirradiation . intrathyroidal metastasis is an uncommon presentation in the clinic though higher incidence rates have been reported in autopsy series ( 1.25%24.4% ) . the thyroid is a highly vascular organ in the body being second only to the adrenal gland . the mechanism of metastasis to the thyroid is by direct invasion from adjacent structures , lymphatic spread , or by hematogenous route . . they may present as part of a widely disseminated disease process or may be the first manifestation of metastasis . the usual presentation is a solitary thyroid nodule and can cause symptoms of esophageal or tracheal compression with massive infiltration of the thyroid . the differential diagnoses include multinodular goiter , primary thyroid cancer such as anaplastic cancer , benign thyroid nodule , follicular dendritic cell tumor , poorly differentiated squamous carcinoma of thyroid , carcinoma showing thymus - like differentiation , and undifferentiated carcinoma . however , in a patient with a history of cancer , the nodule is most often malignant . it is easy , cost - effective , and has high sensitivity , specificity , and negative predictive value . treatment is usually determined by the extent of disease ( localized or as a part of disseminated disease ) and the dfi between treatment of the index cancer and the metastases . in the absence of any other site of metastases , surgery in the form of lobectomy , hemithyroidectomy , or total thyroidectomy our patient underwent hemithyroidectomy as it was a well - defined nodule confined to one lobe of thyroid , with no evidence of distant metastasis . thyroidectomy , when the thyroid is the only site of metastasis , could help avoid further dissemination of cancer , without affecting the survival . however , when complete resection is not possible due to infiltration of adjacent structures such as trachea and esophagus , there is a high risk of local recurrence which can be very difficult to treat and can cause significant distress to the patient . , certain factors including the dfi , performance status of the patient , volume and location of disease , and feasibility of delivering effective , salvage treatment determine the utility and efficacy of adjuvant therapy . four years later , the patient developed a thyroid mass which was treated with total thyroidectomy followed by concurrent chemoradiotherapy . the second case by jankowska et al . concerned a 33-year - old woman with recurrent nasopharyngeal carcinoma with thyroid metastasis after an interval of 4 years , who underwent lobectomy followed by postoperative chemoradiotherapy . in case of primary differentiated thyroid cancer , postoperative external beam rt is indicated in the cases of gross extrathyroidal extension , positive margins , t4-disease , and high nodal burden . in other head and neck squamous cell cancers , patients at a high risk of local recurrence with microscopically involved resection margins or extracapsular spread of disease experience higher locoregional control and disease - free survival with the use of adjuvant concurrent chemoradiation . in this case , the patient had high - risk features in the form of gross residual and microscopic positive margins . as the patient was in good general condition with no distant metastasis or comorbidities and since the low neck had received only 50 gy in the previous treatments , and moreover the present disease being in the thyroid bed and medially , it was decided to offer the patient a full - course reirradiation with concurrent chemotherapy . although this was the third time that the patient was receiving radiation , the decision was justified as there was no evidence of distant metastasis and local recurrence which would have a poor outcome with an adverse effect on the qol of the patient . several factors should be kept in mind while considering patients for reirradiation : ( 1 ) the indication for reirradiation and alternative treatment available , ( 2 ) time since previous treatment , ( 3 ) volume to be treated and the degree of overlap between the previously irradiated structures , ( 4 ) late sequelae of previous treatment , ( 5 ) type of radiation delivery reirradiation in inoperable patients has poor outcomes with survival rates of 13%20% but as an adjunct to surgery has shown better disease control and survival . the patterns of nodal recurrence are difficult to predict in a previously treated neck , whether postneck dissection or post - rt . nonregional lymph node metastases are also noted , attributable to retrograde dissemination due to blockage of lymphatics . unexpected lymph node metastasis could occur despite the inclusion of standard first echelon lymph nodes in the target volume . hence , only the tumor bed and the involved lymph node stations were included in the target volume in our patient . conformal techniques such as three - dimensional conformal radiotherapy and imrt help deliver higher tumoricidal dose with greater normal tissue sparing and lesser toxicity compared to conventional techniques . this is important as the target volume is in proximity to several critical structures such as spinal cord , esophagus , larynx , and trachea . the dose of repeat radiation is another point of concern with a dose more than 60 gy having better outcomes , however with increased risk of late toxicity , about 30%40% in the form of skin breakdown , cartilage necrosis , and esophageal stricture . hence , while deciding on the use of reirradiation , the benefit should outweigh the risks involved . this case report highlights how integration of cancer - directed treatment and palliative care interventions improves symptoms and qol . laskar and lewis in their editorial on qol in hnc report high symptom burden and poor qol in advanced hnc patients undergoing cancer - directed treatment . an observational study by lewis et al . have reported a high incidence of pain and distress among hnc patients undergoing chemoradiotherapy . these views were supported by an observational study by lal et al . an evidence - based review by talapatra et al . on palliative rt in advanced hnc has recommended using disease - specific qol instrument for qol assessment , symptom control , and psychosocial support during the cancer - directed treatment . an aiims study of 100 patients of advanced hnc by gandhi et al . showed that pain , insomnia , fatigue , and loss of appetite were the common symptoms in hnc patients , and there was 50% reduction in global qol and emotional functioning in these patients . hence , an integrated , simultaneous , and shared care model of palliative care delivery is essential for prompt management of symptoms and improvement in qol throughout the illness trajectory . nasopharyngeal carcinoma arising as the second primary in a known case of oropharyngeal carcinoma is uncommon . radical treatment should be considered in patients with a good general condition , in the absence of distant metastasis . concurrent disease - modifying measures with palliative approach improve qol and achieve symptom control . the second primary is one of the long - term sequelae following treatment in hncselection of patients for reirradiation is critical . patients with a good performance status , long dfi , and a small volume of recurrence may be amenable for reirradiationconcurrent cancer - directed treatment and palliative care measures in advanced hnc patients improve symptoms and qol . the second primary is one of the long - term sequelae following treatment in hnc selection of patients for reirradiation is critical . patients with a good performance status , long dfi , and a small volume of recurrence may be amenable for reirradiation concurrent cancer - directed treatment and palliative care measures in advanced hnc patients improve symptoms and qol . there are no conflicts of interest . the second primary is one of the long - term sequelae following treatment in hncselection of patients for reirradiation is critical . patients with a good performance status , long dfi , and a small volume of recurrence may be amenable for reirradiationconcurrent cancer - directed treatment and palliative care measures in advanced hnc patients improve symptoms and qol . the second primary is one of the long - term sequelae following treatment in hnc selection of patients for reirradiation is critical . patients with a good performance status , long dfi , and a small volume of recurrence may be amenable for reirradiation concurrent cancer - directed treatment and palliative care measures in advanced hnc patients improve symptoms and qol .
thyroid gland is an uncommon site of metastasis , and metastasis to the gland secondary to nasopharyngeal carcinoma is seldom seen . 
 we were only able to identify eight reported cases in the literature . a 61-year - old man , diagnosed case of nasopharyngeal cancer  second primary ( first primary - oropharynx ) , was found to have a thyroid nodule on routine follow - up positron emission tomography - computed tomography ( pet - ct ) scan 
 . 
 there was no evidence of metastases at any other sites . 
 the thyroid nodule was confirmed as metastatic carcinoma by fine needle aspiration cytology . 
 he was treated with multimodal treatment comprising of surgery followed by reirradiation with concurrent chemotherapy . 
 subsequently , at the first follow - up ( 2 months after completion of all treatment ) , the patient remained asymptomatic , but the response assessment with pet - ct scan was suggestive of lung metastases with no evidence of locoregional disease . 
 although thyroid parenchymal metastasis is an uncommon occurrence and signifies a poor prognosis , in appropriately selected patients , aggressive therapy with reirradiation and chemotherapy may improve local control and quality of life .