From the Guidelines
The presence of follicular cells in a thyroid biopsy is a key diagnostic feature, as it can indicate a range of thyroid lesions, including follicular adenoma or carcinoma.
Significance of Follicular Cells
- Follicular cells are a crucial component in the diagnosis of thyroid lesions, as they can indicate the presence of follicular adenoma or carcinoma 1.
- The diagnosis of follicular lesions typically requires a minimum of 6-8 groups of follicular cells, with at least 10 cells per group.
- In cases where follicular cells are present, further evaluation with immunohistochemical stains, such as thyroglobulin and TTF-1, may be necessary to confirm the diagnosis 1.
Treatment and Management
- Treatment with levothyroxine (50-200 mcg daily) may be initiated to suppress thyroid-stimulating hormone (TSH) levels.
- The presence of follicular cells can also indicate the presence of papillary and follicular carcinomas, which are known as differentiated thyroid carcinomas (DTC), representing 84% and 11% of all thyroid malignancies, respectively 1.
- Molecular profiling has distinguished two major classes of papillary thyroid carcinomas (PTC) characterized by BRAF-predominant and RAS-predominant molecular signatures 1.
- RET/PTC rearrangements produce a chimeric oncogenic protein resulting from the fusion of the tyrosine kinase domain of RET with the 5' portion of various partners constitutionally expressed in thyroid follicular cells 1.
From the Research
Significance of Follicular Cells in Thyroid Biopsy
The significance of follicular cells in a thyroid biopsy can be understood by examining the role they play in the diagnosis of thyroid follicular neoplasms.
- Follicular cells are a key component in the diagnosis of follicular adenoma and follicular carcinoma, as their arrangement and characteristics can indicate the presence of a neoplasm 2.
- The cytological features of follicular cells, such as crowding, irregular arrangement, high nucleo-cytoplasmic ratio, nuclear atypia, and coarse granular or dense chromatin, can be indicative of malignancy 2.
- The diagnosis of follicular neoplasms can be challenging, and the misclassification of follicular thyroid lesions as benign can lead to devastating clinical outcomes, highlighting the importance of accurate diagnosis 3.
Diagnostic Challenges
The diagnosis of thyroid follicular neoplasms is challenging due to the lack of obvious discriminatory cytological and microarchitectural features.
- Computerized methods have been developed to detect and classify follicular adenoma, follicular carcinoma, and normal thyroid based on nuclear chromatin distribution from digital images of tissue 4.
- Molecular testing can assist in the identification of characteristic molecular alterations, such as GLIS gene rearrangements for hyalinizing trabecular tumor, in FNA samples 5.
- The risk of malignancy in patients with follicular neoplasms is significant, with one in four patients having a thyroid carcinoma, and certain factors such as large nodule size and male gender can increase this risk 6.
Importance of Accurate Diagnosis
Accurate diagnosis of thyroid follicular neoplasms is crucial to prevent misclassification and ensure appropriate treatment.
- A thorough evaluation of specimens by an experienced pathologist is essential to minimize the clinical risk of misdiagnosis 3.
- Long-term follow-up of serum thyroglobulin levels can help identify patients with misclassified follicular thyroid lesions 3.
- Advances in molecular testing and computerized methods can improve the accuracy and reliability of aspiration cytology, enabling better diagnosis and treatment of thyroid follicular neoplasms 2, 5, 4.