Answer:

After an ultrasound reveals a TI-RADS 4 thyroid nodule, indicating suspicious characteristics, doctors typically recommend a fine needle aspiration (FNA). This procedure directly examines cells within the nodule to determine if it is benign or malignant.

Following the FNA, the cell sample undergoes testing and is classified according to the Bethesda system, which comprises six groups, from I to VI. Each group reflects distinct cellular characteristics and varying degrees of malignancy risk. Based on these results, doctors decide on the appropriate course of action, which may include monitoring, repeat FNA, additional testing, or surgery.

TI-RADS is a system for assessing the malignancy risk of thyroid nodules based on ultrasound imaging. Bethesda, conversely, is used to classify cell samples obtained from the nodule through fine needle aspiration.

Specifically, Bethesda I indicates that the cell sample is insufficient or inadequate for diagnosis, necessitating a repeat FNA. Bethesda II signifies a benign lesion with a low risk of malignancy, and patients are usually advised to continue monitoring.

Doctor Hai consults a patient about thyroid cell aspiration results. Illustration: Tam Anh General Hospital

Bethesda III is an indeterminate group, where cells show some abnormalities but cannot be definitively classified as benign or malignant. Bethesda IV denotes a follicular neoplasm, where cytology cannot conclusively distinguish between a benign lesion and follicular cancer. Bethesda V suggests suspicious for malignancy, indicating a high risk of cancer. Bethesda VI confirms malignancy, with cytology consistent with thyroid cancer.

Your thyroid aspiration result, classified as Bethesda II, suggests that your thyroid nodule is highly likely to be benign. If the ultrasound images and the nodule show no other abnormal signs, you should undergo regular monitoring and follow-up appointments as scheduled by your doctor.

In some instances, even if an FNA result is benign, doctors may consider a repeat aspiration or further evaluation if the ultrasound reveals suspicious characteristics of the thyroid nodule, rather than relying solely on one test result.

You should adhere to your follow-up schedule and undergo periodic ultrasounds as directed to assess the nodule's size and morphology, thereby guiding further monitoring or treatment.

Master of Science, Doctor Tran Ngoc Hai

Department of Oncology

Tam Anh General Hospital Ha Noi