although surgery is recommended for ptc , there is no consensus on the therapy when a thyroidectomy is contraindicated because of systemic disease such as heart failure or chronic obstructive pulmonary disease .
hypertrophic cardiomyopathy is a common genetic cardiovascular disease with a high risk of sudden death and disability ( 1 ) .
given the potential devastating perioperative cardiac complications , hypertrophic cardiomyopathy is generally a contraindication for anesthesia and surgery ( 2 ) .
radiofrequency ablation ( rfa ) has been used widely in the treatment of solid cancers ( 3 ) .
herein , we presented a case of ptc in a patient with hypertrophic cardiomyopathy treated with rfa .
neck ultrasound performed for a 52-year - old female revealed a predominantly solid nodule ( 0.9  0.7  0.5 cm ) with marked hypoechogenicty , microcalcification , moderate vascularity , and spiculated margin in the right thyroid gland .
total thyroxine ( tt4 ) and total triiodothyronine ( tt3 ) were 109.60 nmol / l ( 55.47161.25
nmol / l ) and 1.16 nmol / l ( 1.022.96 nmol / l ) ; free thyroxine ( ft4 ) and free triiodothyronine ( ft3 ) were 14.63 pmol / l ( 10.4524.38 pmol / l ) and 4.36 pmol / l ( 2.776.31
pmol / l ) , respectively . thyroid - stimulating hormone ( tsh ) and thyroid peroxidase antibody ( tpo - ab ) were 1.58 miu / l ( 0.3804.340
miu / l ) and 852.0 iu / ml ( 0100 iu / ml ) , respectively .
seven years earlier , the patient had been diagnosed with hypertrophic cardiomyopathy and a ddd cardiac pacemaker was implanted .
a cardiac ultrasound showed diffuse thickening of the ventricular walls and the left ventricular ejection fraction was 60% .
the n - terminal pro - brain natriuretic peptide was 1048 pg / ml ( 0100 pg / ml ) .
core needle biopsy ( 18 g needle ) confirmed the diagnosis of ptc ( fig .
the patient was considered unable to tolerate a thyroidectomy , so instead rfa was performed .
we used valleylab cool - tip rfa system ( boulder , co , usa ) , including monopolar electrode , radiofrequency generator and cool - tip pump .
after sterilization and local anesthesia with 2% lidocaine , the ablation electrode was inserted into the nodule under ultrasound guidance .
the ablation was started with 5 w and increased to 28 w gradually in a 1 cm active tip .
it was terminated when the rfa - induced transient hyperechoic zone covered the entire carcinoma and the needle passage was also ablated when the ablation electrode was retracted .
regular follow - up neck ultrasound showed no signs of recurrence or metastases after 1 , 3 , 15 , and 41 months ; and the patient had no complications of rfa ( fig .
the size of ablated lesion was reduced and the echogenicity was decreased ; in addition , the tt4 and tt3 were 73.20 nmol / l ( 55.47161.25
nmol / l ) , respectively ; ft4 and ft3 were 14.02 pmol / l ( 10.4524.38 pmol / l ) and 3.76 pmol / l ( 2.776.31
tsh and tpo - ab were 0.97 miu / l ( 0.3804.340 miu / l ) and 670.70 iu / ml ( 0100 iu / ml ) ; respectively .
ptc is the most common subtype of thyroid cancer , comprising > 80% malignant thyroid neoplasms .
although the prognosis is excellent , the guidelines of the national comprehensive cancer network for thyroid carcinoma and the european thyroid association ( eta ) both recommend a total thyroidectomy or lobectomy plus isthmusectomy as the standard treatment for ptc ( 56 ) .
a non - surgical or minimally invasive treatment is required in thyroid cancer patients who can not undergo surgery due to severe disease , such as hypertrophic cardiomyopathy . as minimally invasive therapy
, rfa induces irreversible damage to tumor tissue with heat generated by high - frequency alternating electric current ( 7 ) .
rfa is an established substitute for surgery for solid cancers such as hepatic cancer ( 3 ) .
rfa is also used to treat benign thyroid nodules and metastatic or recurrent well - differentiated thyroid cancer with difficult reoperations ( 89 ) . the residual volume after rfa
is reduced significantly in benign thyroid nodules and metastatic well - differentiated thyroid carcinoma ( 89 ) . however , whether rfa is a promising therapeutic option for papillary thyroid microcarcinoma ( ptmc ) , which defined as thyroid cancer  10 mm in diameter , is unclear .
( 10 ) proposed the moving shot technique ( mst ) for ablation of thyroid nodules by moving the electrode during the procedure . compared with fet , mst is more suitable for thyroid gland since it can minimize the risk of heat damage to surrounding critical structures such as recurrent laryngeal nerve , blood vessels and esophagus ( 11 ) . however , at the time , mst was not in use for thyroid nodules in our hospital , and may have been more suitable for this patient .
eta and the american association of clinical endocrinologists recommend partial thyroidectomy and lobectomy plus isthmusectomy for ptmc without neck lymph nodes involvement respectively ( 512 ) . in our case ,
a calcified 0.9  0.7  0.5 cm nodule without enlarged lymph nodes was detected and core needle biopsy confirmed papillary thyroid cancer , so surgery was necessary for the patient . although surgery is the main therapy for ptmc , our case demonstrates that rfa can be a substitute in patients who can not tolerate surgery .
however , neck lymph nodes metastases are quite common for thyroid cancer and central node involvement reportedly exist in 64% of ptmc cases ( 13 ) .
therefore , for operable thyroid cancer , rfa should be avoided because of undetectable lymph node metastases and patients undergoing rfa as an alternative to surgery should be followed closely .
signs of recurrence or metastases have not been observed on periodical follow - up neck ultrasound in our patient .
however , further observation and clinical trials are needed to compare the value of rfa with surgery .
rfa may be a reliable therapeutic candidate even for low - risk ptc patients without contraindication of surgery . in conclusion , to our knowledge , this is the first reported case of ptc with hypertrophic cardiomyopathy treated with rfa . despite thyroidectomy as prior therapy in our case , rfa is an alternative when surgery is not feasible .
however , further long - term observation is needed to confirm the value of rfa in the treatment of thyroid cancer .
 standard therapy has not been established for thyroid cancer when a thyroidectomy is contraindicated due to systemic disease . herein , we reported a patient who had hypertrophic cardiomyopathy and papillary thyroid carcinoma treated by radiofrequency ablation because of inability to tolerate a thyroidectomy . 
 radiofrequency ablation can be used to treat thyroid cancer when surgery is not feasible , although the long - term outcome needs further observation . 
INTRODUCTION
CASE REPORT
DISCUSSION