in addition , more than 50% of the population have thyroid nodules detected at ultrasonographic ( usg ) examination .
noninvasive methods such as radionucleide thyroid scintigraphy and thyroid usg have been used for the diagnosis of thyroid nodules for decades .
fine needle aspiration biopsy ( fnab ) guided by usg or palpation is the most feasible diagnostic tool for thyroid nodule evaluation due to low false positive ( 2% ) and false negative rates ( 4% ) .
however , like other invasive procedures , fnab may also lead to various complications . in this paper
seventy - one years old male patient was admitted to the hospital with the complaints of a swelling and discharge on the anterior neck wall .
these complaints were present for 10 days . in the medical history of the patient ,
similar complaints were present 15 to 20 days after fnab of thyroid gland performed four years ago , and these complaints had spontaneously resolved with antibiotics within one month . at that time , no surgical intervention related to this complaint was performed .
physical examination of the patient revealed a sinus opening with seropurulant discharge located at midline , two cm caudal to thyroid cartilage and the tissues surrounding the sinus opening were moderately swollen and hyperemic ( figure 1 ) .
there was also a palpable nodule four cm in size with circumscribed margins located in the left lobe of thyroid gland .
white blood cell count , neutrophil , eosinophil , c reactive protein , sedimentation rate , liver and thyroid function tests , and antithyroid antibodies were all in normal range .   in cervical usg
, there was a nodule 46  32  mm in size with multiple calcifications and mixed echogenities in the left thyroid lobe and it was pushing trachea away from the midline . at thyroid scintigraphy , the nodule was hypoactive and almost filling the whole lobe of the thyroid gland .
in addition to this nodule , there was asymmetrical thickening of tracheal wall on the left side starting from the level of epiglottis and obliterating lateral recess at the level of eustachian tube in computerized tomography ( ct ) .
the contrast material given through the opening of the sinus passed neither to trachea nor to esophagus and the sinus was completely intrathyroidal ( figure 2 ) .
usg - guided fnab with 25 gauge needle was performed for the nodule located in the left lobe of thyroid gland .
the cells , with prominent nucleus and elongated cytoplasm , fragmented connective tissue elements and polimorphonuclear cells were noted at cytological evaluation .
pet - ct was also performed with the suspicion of undifferentiated thyroid malignancy infiltrating the skin .
moderate 18-fdg uptake seen on the left side of the neck from epiglottic level to cephalad direction was interpreted as an inflammatory process . however , 18-fdg uptake by thyroid nodule was reported to be suspicious for malignancy . with these radiological and clinical findings , bilateral total thyroidectomy was performed .
methylene - blue dye was injected through the opening of sinus tract at the beginning of surgery .
although the dye was totally intrathyroidal , the sinus tractus , prethyroidal muscles , and the skin were resected with the specimen .
the sinus tract was continous with the left lobe of thyroid gland and there were severe inflammatory adhesions around the ligament of berry at this region .
the dissection of the left lobe was quite difficult , and central lymph node dissection was also performed .  
the histopathological examination of the specimen revealed that the sinus tract was formed by spindle cell proliferation and the tract was fixed to prethyroideal muscles .
spindle cell proliferation and inflammatory cell infiltration within vascular structures were responsible for adhesions between thyroid gland and prethyroideal muscles .
hurtle cell changes confined within the bounderies of the nodule were noted outside the fistulous tract .
these areas were stained with cd56 , ck19 , and hbme1 and not with gal3 and p53 . the other lobe and isthmus
the diagnosis of the nodule was benign and the patient is still followed with no complications .
fnab is used for rapid cytologic diagnosis of not only thyroid nodules but also soft tissue masses of head and neck area with low morbidity rate .
it is thought that these complaints are related to small hematomas occuring during needle enterance to the gland .
most hematomas are self - limiting and do not cause serious problems . for many years , it has been a subject of discussion that fnab of thyroid cancers has a risk of seeding of malignant cells through needle track . in the literature , there are a few reports on subcutaneous nodule formation due to malignant cell implantation after fnab and this was accepted as a rare cause of thyroid cancer recurrence . besides , other rare complications have also been reported as case reports .
these are intrathyroidal massive hemorrhage and upper respiratory tract congestion , nodule infarction , recurrent laryngeal nerve palsy , tracheal injury related hemoptysis , and pleural injury resulting in pneumothorax . to the best of our knowledge , there are two case reports about sinus formation through the needle track in the english literature .
the diagnosis of the first reported case was in a patient with riedel thyroiditis and it is well known that fistulas and sinuses can be seen in this disease after surgery or percutaneous manipulations .
the second case was reported from india and the reason for sinus formation was needle - track seeding of papillary thyroid cancer cells . in the case presented here , we did not suspect about riedel thyroiditis because of localized proliferation in the lesion .
the diagnosis was not inflammatory fibrous tumor , due to alk and desmin negativity and sinus tract formation .
anaplastic carcinoma was also excluded , since there were no atypical and ck positive cells between fibroblasts and the history of the disease was quite long .
this is the first report about thyro - cutaneous sinus formation after fnab of a benign thyroid nodule .
the vasculature of thyroid gland increases and expands in cases of noduler goiter with hyperthyroidism .
thyroid nodules also have some aberrant vessels and these vessels are relatively thin - walled .
it is thought that these vessels running in tissue planes between nodules and surrounding thyroid lobules rupture due to penetrating trauma caused by fnab .
intrathyroidal hemorrhage appears to be commonly associated with multinodular goiters that have thin - walled , abundant vessels .
many small hematomas heal with formation of minimal fibrosis and scar tissue , but rarely a hematoma can cause widespread inflammation by increasing vascular and fibroblastic proliferative activity . this inflammation or hemorrhagic necrosis can cause formation of a sinus or fistula by fixation of a large nodule to the prethyroid muscles .
the case presented here was operated with the suspicion of thyroid malignancy when there was active inflammation in the tissues .
minor tissue traumas during the dissection of areas with severe inflammation were thought to be the reason for esophago - cutaneous fistula development . in practice , 25 gauge needles are recommended to obtain sufficient tissue sample during thyroid needle biopsy . however , especially for larger solitary nodules , it may be advisable to use thinner needles to reduce local trauma . for the patients with needle biopsy related inflammation ,
 fine needle aspiration biopsy is the most feasible , safe , and accurate diagnostic tool for thyroid nodule diagnosis . 
 the development of a sinus tract between thyroid gland and the skin through needle tract after fine needle aspiration biopsy is an extremely uncommon phenomenon . 
 in this paper , 
 a 71-year - old man presenting with a swelling and discharge on the anterior neck wall was reported . 
 similar complaints were present 15 to 20 days after fine needle aspiration biopsy of thyroid gland four years ago . 
 bilateral total thyroidectomy was performed considering a thyroid malignancy infiltrating the skin . 
 histopathologic examination confirmed a sinus tract between the thyroid gland and skin and thyroid nodule was benign in nature . 
 it must be kept in mind that inflammatory reactions might also occur after fine needle aspiration biopsy of benign thyroid nodules . in patients with needle biopsy - related inflammation 
 , surgery may be delayed until the inflammation subsides . 
 
1. Introduction
2. Case
3. Discussion