A 35 year old female presents with lump in the anterior triangle of neck. True about FNAC:
**Core Concept**
Fine-needle aspiration cytology (FNAC) is a diagnostic tool used to investigate lumps in the neck, particularly those in the anterior triangle. FNAC involves the insertion of a thin needle into the lump to collect cells for cytological examination, helping to differentiate between benign and malignant lesions.
**Why the Correct Answer is Right**
The correct answer is related to the **sensitivity and specificity** of FNAC in diagnosing thyroid lesions. FNAC is a reliable method for distinguishing between papillary thyroid carcinoma, follicular thyroid carcinoma, and benign thyroid lesions. The procedure involves examining the cellular architecture and morphology, including features such as nuclear grooves, pseudoinclusions, and the presence of papillae. FNAC has a high sensitivity for detecting papillary thyroid carcinoma, which is characterized by the presence of these specific cellular features.
**Why Each Wrong Option is Incorrect**
**Option A:** FNAC is not a definitive diagnostic method for thyroid lesions, as it may yield inconclusive results or false negatives. This is particularly true for follicular thyroid carcinoma, which requires histopathological examination of the entire tumor to confirm the diagnosis.
**Option B:** FNAC is not a contraindication for thyroid surgery, but rather a diagnostic tool used to guide surgical decision-making. A false-negative result on FNAC does not necessarily preclude the need for surgical excision, especially if clinical suspicion for malignancy remains high.
**Option C:** FNAC is not a substitute for histopathological examination in the diagnosis of thyroid lesions. While FNAC is useful for distinguishing between benign and malignant lesions, it may not provide sufficient information to confirm the histological type of thyroid cancer.
**Clinical Pearl / High-Yield Fact**
When interpreting FNAC results, it's essential to remember that a **"suspicious for malignancy"** result does not necessarily confirm cancer, but rather indicates the need for further investigation, including histopathological examination and possibly surgical excision.
**Correct Answer:** C.