ANAPLASTIC THYROID CANCER – Importance of preoperative diagnosis

Introduction

Anaplastic thyroid cancer – importance of preoperative diagnosis.-Anaplastic thyroid cancer is one of the most aggressive human malignant tumors. Fortunately, it is relatively rare, accounting for 1 -2 % of primary thyroid carcinomas. It usually occurs in elderly women (peak incidence: 6th – 7th decades of life). Interestingly, many of these patients have a history of previous multinodular goiter

Common ultrasonographic features of anaplastic thyroid cancer

Common, but no specific, ultrasonographic features in patients with anaplastic thyroid cancer include:

• Hypoechogenicity, diffuse, involving the whole lobe or thyroid gland

• Ill-defined margins

• Necrotic degeneration

• Nodal metastases (often with distant metastases)

• Extracapsular spread

• Vascular invasion

• Microcalcifications

• Small intranodular vessels (on color Doppler ultrasonography)

• Hard texture (on elastography)

Ultrasound-guided cytology / biopsy

Ultrasound-guided Fine-Needle Aspiration and cytology of the aspirates is the diagnostic procedure of choice for the preoperative diagnosis of thyroid cancer. However, in anaplastic thyroid cancer, the diseased thyroid parenchyma may have a dense fibrotic texture and FNA may not be adequate; therefore, ultrasound-guided core needle biopsy may be required.

Preoperative identification of anaplastic thyroid cancer – clinical significance

Anaplastic thyroid carcinoma is an aggressive malignant tumor, often unresectable, due to diffuse infiltration of adjacent anatomic structures. Preoperative diagnosis of anaplastic thyroid carcinoma is based on ultrasonographic findings and findings of ultrasound guide FNA or tru-cut (core-needle) cytology / biopsy.

Preoperative identification is important to avoid unnecessary surgery in patients with extensive local spread of the disease. Even open (surgical) biopsy can be avoided in these patients. In unresectable anaplastic thyroid cancer the role of surgery is mainly palliative, aiming to maintain airway patency.