Endocrine Abstracts

Anaplastic thyroid carcinoma (ATC) is a rare form of thyroid carcinoma that is associated with an extremely poor prognosis. Ultrasonography (US) and subsequent fine needle aspiration biopsy (FNAB) are the first diagnostic methods in the assessment of a palpable thyroid mass. Nevertheless, some clinical and US features of ATC are not specific. Here, we report on an extremely rare case of ATC masquerading as subacute thyroiditis (SAT).

A 40-year-old woman was admitted to our hospital for an examination of a rapidly growing thyroid mass with slight pain in the neck. Three weeks before admission, the patient noticed the mass on the right side of her neck, with discomfort while swallowing. The woman had a history of antecedent viral symptoms. Physical examination revealed an approximately 3 cm hard and tender mass palpable on the right thyroid lobe. The laboratory inflammation markers, except for the erythrocyte sedimentation rate, were within normal range. Thyroid hormones concentration and antithyroglobulin antibodies were normal. A chest X-ray and the abdominal US didn‘t show any pathology. Thyroid ultrasound revealed a 3.4×2.6 cm mass with marked hypoechogenicity, ill-defined margins, and no blood supply. Reactive and enlarged neck lymph nodes (level III–IV) were detected. Sonographically, the thyroid lesions were indicative of SAT differentiated from thyroid abscess. FNAB from suspicious thyroid was performed. On cytologic examination, tumor cells with plentiful of neutrophils were assessed, while the direct smear and culture were negative for bacteria. Total thyroidectomy and enlarged neck lymph node dissection were performed. The post-surgical pathologic assessment did not reveal any lymph node metastasis. Histopathologically, ATC was evaluated.

This case demonstrates an extremely rare case of ATC that mimics SAT and thyroid abscess. In the case of atypical clinical and ultrasonographic features of SAT, a careful examination for thyroid malignancy should be proposed.