Fine‐needle aspiration of anaplastic thyroid carcinoma with varied cytologic and histologic patterns: A case report

Abstract

Anaplastic carcinoma of the thyroid (ACT) is a rare subtype of thyroid neoplasm. This tumor represents approximately 5-10% of all thyroid malignancies and its poor prognosis has not changed in 25 years. ACT often arises in a long-standing thyroid nodule and has been documented to be associated with a variety of more well-differentiated thyroid carcinomas. We describe the cytologic features of a case in which the patient had a 10-yr history of a thyroid nodule. The ACT in this case had a cytologic and histologic appearance of several different subtypes of thyroid carcinomas.

Anaplastic Thyroid Carcinoma in Fine Needle Aspirates

“…7,22,28,30,37 This has also been observed in FNAB samples. 5,19,38 Differences in reported incidence are most probably due to inadequate sampling. In one of our PC cases a small surgical biopsy missed the ATC component, while FNAB failed to include anaplastic component in six cases.…”

“…[4][5][6]8,9,11,13,16,18,19,23,24,29,34 Luze's article on 33 ATC cases and 10 cases of malignant hemangioendothelioma focuses mainly on the differential diagnosis between these two entities in smears. 24 It is generally believed that cytologic features of ATC in smears are highly specific and easy to recognize.…”

“…[4][5][6]8,9,11,13,16,18,19,23,24,28,34 The purpose of this retrospective study was to analyze the diagnostic problems with FNAB in ATC and to describe the cytomorphologic characteristics in a series of 113 cases.…”

Encapsulated Anaplastic Thyroid Carcinoma Transformed from Follicular Carcinoma

“…Survival rates may actually be influenced by the percentage of ATC in an otherwise differentiated thyroid carcinoma. 13 ATC occurring in combination with a better differentiated carcinoma of the thyroid diagnosed by FNAB has been described in widely invasive tumors [14][15][16][17] but rarely in circumscribed resectable lesions. Papillary carcinoma followed by poorly differentiated and follicular carcinoma are most frequently cited to coexist or as precursors to ATC in both FNAB and surgical specimens.…”

Solitary Thyroid Nodule

“…[65][66][67] A mixed morphology is usually seen. Anaplastic carcinoma of the thyroid gland is an aggressive neoplasm that usually shows a cellular smear with frankly malignant cells with a background of necrosis and tumor diathesis.…”