Papillary thyroid cancer case masked by subacute thyroiditis

Abstract

Subacute thyroiditis (SAT) association with thyroid carcinoma has been rarely reported in the literature. We present a patient with SAT and papillary thyroid cancer that was suspected by ultrasonographic evaluation (US) following SAT treatment. A fifty-four-year old female patient referred to our department due to tachycardia, jitteriness and pain in cervical region for the past one month. SAT diagnosis was established by physical examination, laboratory and ultrasonographic findings. After treatment, control thyroid US revealed regression of the hypoechogenic regions seen in both lobes, and a previously unreported hypoechogenic lesion with microcalcification focus that had irregular borders and was not clearly separated from the surrounding parenchyma located in the posterior aspect of the lobe (Elasto score: 4, Strain index: 7.08). Fine needle aspiration biopsy was taken from this nodule; cytology was assessed to be compatible with papillary thyroid carcinoma. Postsurgical pathology evaluation showed a papillary microcarcinoma. SAT may produce ultrasound changes that obscure the coexistence of papillary carcinoma. We recommend that patients with SAT have ultrasonography after they recover. Hypoechogenic regions bigger than 1 cm that are present in the follow-up post-therapy US should be assessed by biopsy.

Cytologic Features of Subacute Granulomatous Thyroiditis Can Mimic Malignancy in Liquid‐Based Preparations

“…In a series of 31 histologically confirmed cases, a cytological suspicion of malignancy was rendered in 13 cases and only in 3 the cytological features of SGT were present in the preoperative FNAB . In addition, SGT may coexist and mask other lesions such as papillary carcinoma . MGC and granulomas, two of the main features of SGT, are also seen in other benign and malignant thyroid conditions .…”

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

“…Therefore, it was recommended to get another ultrasonography examination when the symptoms had resolved and laboratory values have returned to normal in order to rule out an underlying nodular disease (13). Recently, a case of subacute thyroiditis (granulomatous thyroiditis) described a malignant thyroid nodule (0.9 cm) with microcalcification focus found only at control thyroid ultrasound done after clinical and laboratorial recovery (15). Our patient presented a difuse heterogeneous hypoechoic pattern associated with suspicious thyroid nodule.…”

“…In most studies, thyroid cancer is associated with granulomatous form of thyroiditis (12)(13)(14)(15). The diagnosis of thyroid cancer can be challenging because subacute thyroiditis can result in ultrasound changes that obscure the coexistence of papillary carcinoma.…”

“…Neck ultrasound is highly sensitive in diagnosing of lymph node involvement by thyroid cancer (15,24). Even with the presence of specific characteristics of malignancy, such as cystic appearance, hyperechoic punctuations, loss of hilum and peripheral vascularization, the diagnosis of cervical lymphadenopathy can be frequently complex (26).…”

Diagnostic cytological features and differential diagnosis of subacute granulomatous (De Quervain's) thyroiditis

“…According to our data and the literature, SGT may coexist with thyroid carcinomas and may also mimic some of their cytological features. This may result in false‐positive diagnoses and unnecessary resections . Cytological features of SGT that mimic other thyroid lesions should be well recognized to prevent false cytological diagnoses, false positivity, and unnecessary surgical resections.…”