Anaplastic carcinoma of the thyroid (ATC) is a type of thyroid cancer, which has the worst prognosis amongst all thyroid malignancies. It is known to progress rapidly and is responsible for nearly half of the deaths that result from thyroid cancer.
Anaplastic thyroid carcinoma (ATC) is considered a fatal type of cancer as the average survival period after diagnosis is approximately 4 months  . Patients who are affected by ATC are primarily elderly with an average age of 70 years .
Individuals present both with non-specific symptoms and signs which are clinically indicative of the diagnosis of thyroid malignancy. Amongst the former are a non-productive cough, dyspnea and neck pain . A quickly growing neck mass may have already been noticed by the patient, and dysphagia is a symptom that can be considered more specific to a thyroid pathology. Other symptoms may be observed, such as Horner's syndrome, which encompasses the triad of hemifacial anhidrosis, miosis, and partial blepharoptosis; a recently acquired hoarse voice may also be reported, due to local invasion of the vocal cords .
Unfortunately, studies have documented as many as 50% of the patients as being diagnosed at a time when distant metastases have already developed  . Skeletal and pulmonary malignant metastatic invasion is the most common type, and those individuals complain of bone pain and pulmonary symptoms. Invasion of the brain parenchyma by cancer cells will lead to various neurological symptoms and regional enlargement of lymph nodes indicates a metastasis to adjacent structures. Weakness, malaise, and weight loss may also be reported as a general complaint and symptoms resulting from liver, kidney, pancreas, heart or the adrenal gland may also be reported since these organs also constitute probable sites for metastasis.
A thorough workup for ATC includes a complete medical history, serum laboratory testing, a thoracic radiograph, an ultrasonographic scan (US scan), a positron emission tomography/computerized tomography (PET/CT), a CT scan and a biopsy.
Suspicion of thyroid malignancy, including ATC, is raised when a patient presents with a growing neck mass, dysphagia, neck pain, and cough. A complete blood count (CBC) and standard biochemical profile are the first blood laboratory tests carried out, even though results may not directly point to ATC. TSH levels are mandatory and so is a neck US scan, that can help to initially evaluate the mass and illustrate lymph node invasion . Blood calcium levels can differentiate between an ATC and parathyroid malignancy or medullary thyroid cancer.
Other imaging modalities that are usually employed encompass a CT scan of the neck, that can assess the extent of the tumor and possible local metastasis . CT is a modality that can be used to investigate further, distant metastasis. A fine-needle aspiration biopsy is a test that can render an accurate diagnosis; typical histological features of an ATC are:
ATC requires a meticulous differentiation from thyroid lymphoma. This can be done with the aid of cytoplasmic immunoglobulin measurement and gene rearrangement studies. Thoracic radiography is performed to detect pulmonary metastasis. Lastly, a PET-CT scan is of great value, in order to evaluate distant metastases .