Key Points
- Patients who present with a rapidly expanding neck mass require rapid histopathologic confirmation of the diagnosis.
- If anaplastic thyroid carcinoma (ATC) is diagnosed, the patient’s overall clinical status and TNM stage of the tumor should be determined.
- Treatment goals (aggressive versus supportive care) should be established by disclosing the status and risks/benefits, discussing the patient’s values and preferences, and then having the patient make an informed decision.
- Patients with stage IVA/IVB resectable disease have the best long-term survival, particularly if a multimodal approach (surgery, intensity-modulated radiation therapy [IMRT] for locoregional control, and systemic therapy) is used.
- Patients with unresectable stage IVB disease may also respond to aggressive multimodal therapy.
- Patients with distant metastases (stage IVC) only rarely have responded to traditional therapies, and if an aggressive approach is desired by the patient, a clinical trial should be considered.
- Hospice or palliative care is also an important component of managing patients with stage IVC disease.
Table 1. Recommendation Grading
Diagnosis
Histopathology and Differential Diagnosis
- Morphologic diagnosis with appropriate immunostaining as relevant is mandatory to exclude other less aggressive and treatable entities that can mimic ATC. (S-M)
Cytology and Pathology Procedures
- Fine needle aspiration (FNA) cytology or core biopsy should play a role in the preoperative diagnosis of ATC. In cases in which the limited sampling of FNA or core biopsy yields material that is nondiagnostic, open biopsy should be performed to obtain diagnostic tissue. (S-L)
- Whenever possible, a definitive diagnosis should be obtained prior to surgery. Intraoperative pathology consultation can be used to define the adequacy of the resected tissue for diagnostic evaluation or to identify ATC in a patient when that diagnosis was not anticipated preoperatively. Intraoperative pathology consultation is not usually appropriate for definitive diagnosis. (S-L)
- Pathological evaluation should provide information on the proportion of tumor that comprises ATC and coexistent well-differentiated or poorly differentiated thyroid carcinoma, which may affect prognosis and guide management. (S-L)
- Molecular studies based on DNA/RNA analysis are not currently required for diagnosis and management of patients with ATC. (S-M)
Initial Evaluations
- Adjunctive preoperative radiological tumor staging should not delay therapy and should make use of appropriate cross-sectional imaging including neck ultrasound, CT scans or MRI (for the neck and chest), and PET/CT fusion scans. (S-M)
- Primary management of ATC should not be delayed in order to biopsy tumors at distant sites. If clinically indicated, such biopsies could be performed after completion of primary surgery. (W-L)
- All critical appointments and assessments that are required prior to primary treatment of ATC should be prioritized and completed as rapidly as possible. (S-L)
- Every patient should undergo initial evaluation of the vocal cords. The best way to evaluate the vocal cords is with fiber optic laryngoscopy. However, mirror examination may be acceptable. Fiber optic laryngoscopy will also help to assess the opposite vocal cord, mobility of the vocal cord, endolaryngeal pathology and whether there is any extension of disease in the subglottic or upper tracheal area. (S-L)
- ATC is an aggressive tumor with a poor prognosis and high mortality. Assessment of predictive factors such as age, sex, tumor size, histology, and clinical stage should be performed in all patients. (S-M)
Table 2. Immunohistochemical Markers Useful for the Diagnosis of Anaplastic Thyroid Cancer
Thyroid Cancer Staging CalculatorCEA Doubling Time Calculator
| Immunohistochemical marker | DTC | MTC | ATC | SCC | Lymphoma |
|---|---|---|---|---|---|
| Pankeratin (AE1/AE3) | + | + | +/– | + | –a |
| High molecular weight keratins | + (PTC) – (FTC) | – | –/+ | + | – |
| TTF –1 | + | +/– | –/+ | – | – |
| PAX8 | + | +/– | +/– | – | +/–b |
| Thyroglobulin | + | – | – | – | – |
| Synaptophysin | – | + | – | – | – |
| Chromogranin | – | + | – | – | – |
| Calcitonin | – | + | – | – | – |
| CEA | – | + | – | – | – |
| P53 | – (rare +) | – | + | +/– | +/– |
| E–cadherin | + | – | + | – | |
| B–catenin | membranous | nuclear or – | + / – (nuclear) | ||
| CD45 | + |
a Plasmablastic lymphoma, anaplastic large cell lymphoma, and very rarely some diffuse large B cell lymphomas can express cytokeratin that is detected by AE1/AE3 cytokeratin monoclonal antibodies.
b PAX8 was detected by immunohistochemistry in normal B cells, but was not studied in lymphoma. It is very likely that various lymphomas express PAX8.
Table 3. Residual Tumor (R) Classification
| R0 = | No residual tumor |
| R1 = | Microscopic residual tumor |
| R2 = | Macroscopic residual tumor |
| RX = | Presence of residual tumor cannot be assessed |