Painless thyroiditis associated to thyroid carcinoma: role of initial ultrasonography evaluation

Abstract

Even though it is a rare event, most associations of thyroid carcinoma with subacute thyroiditis described in the literature are related to its granulomatous form (Quervain's thyroiditis). We present a patient with subacute lymphocytic thyroiditis (painless thyroiditis) and papillary thyroid cancer that was first suspected in an initial ultrasound evaluation. A 30-year old female patient who was referred to the emergency room due to hyperthyroidism symptoms was diagnosed with painless thyroiditis established by physical examination and laboratory findings. With the presence of a palpable painless thyroid nodule an ultrasound was prescribed and the images revealed a suspicious thyroid nodule, microcalcification focus in the heterogeneous thyroid parenquima and cervical lymphadenopathy. Fine needle aspiration biopsy was taken from this nodule; cytology was assessed for compatibility with papillary thyroid carcinoma. Postsurgical pathology evaluation showed a multicentric papillary carcinoma and lymphocytic infiltration. Subacute thyroiditis, regardless of type, may produce transitory ultrasound changes that obscure the coexistence of papillary carcinoma. Due to this, initial thyroid ultrasound evaluation should be delayed until clinical recovery. We recommended a thyroid ultrasound exam for initial evaluation of painless thyroiditis, particularly in patients with palpable thyroid nodule. Further cytological examination is recommended in cases presenting with suspect thyroid nodule and/or non-nodular hypoechoic (> 1 cm) or heterogeneous areas with microcalcification focus. Arch Endocrinol Metab. 2016;60(2):178-82

Dynamic follow-up of the effects of programmed death 1 inhibitor treatment on thyroid function and sonographic features in patients with hepatocellular carcinoma

“…The increased classification of thyroid nodules during PD-1 therapy may be related to the unclear margins and irregular shape of nodules caused by inflammation. As one study said, thyroiditis, regardless of type, may produce transitory ultrasound changes that confound the accurate classification of thyroid nodules ( 26 ).…”

Prevalence of papillary thyroid cancer in subacute thyroiditis patients may be higher than it is presumed: retrospective analysis of 137 patients

“…The association of SAT and thyroid carcinoma is a very rare finding, and they were usually published as case reports. 1 , 7 , 8 , 9 , 10 , 11 , 12 The most comprehensive study on this subject is the work of Nishihara et al . in Japanese patients with SAT.…”

“…There are very few studies reporting the prevalence of thyroid cancer in patients with SAT. 1 , 7 , 8 , 9 , 10 In addition to the findings compatible with thyroiditis, ultrasonographic examination of the patients with SAT may also reveal thyroid nodules incidentally. In some patients, pseudo-nodules seen in association with thyroiditis, which cannot be distinguished easily from malignant nodules with irregular margins; and a close follow-up in parallel with the resolution of inflammatory findings of SAT may be helpful in differential diagnosis.…”

Thyrotoxicosis with concomitant thyroid cancer

“…Except for etiologies mentioned above, thyrotoxicosis induced by ATC, HCC and FVPTC have also been described (Kumar et al 2005, Bommireddipalli et al 2010, Ruggeri et al 2013, Rees et al 2015, Daroszewski et al 2018. Additionally, painless thyroiditis-induced thyrotoxicosis has been reported to be associated with PTC (Valentini et al 2016). Moreover, subacute thyroiditis associated with PTC has been found to mainly happened…”

“…In cases with indeterminate thyroid nodule, FNAB is recommended (Valentini et al 2016). Swelling with pain in the thyroid gland are the clinical finding in patients of subacute thyroiditis associated with DTC.…”