This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid Gland, Subject name: Surgery
Thyroid condition which cannot be diagnosed by FNAC is 
Select and explain. 
A. Thyroiditis, B. Medullary carcinoma, C. Lymphoma, D. Follicular carcinoma
D: Follicular carcinoma
Answer: D: Follicular carcinoma 
Explanation: Ans. is 'd' i.e., Follicular carcinoma Fine-needle aspiration cytology* FNAC is the investigation of choice in discrete thyroid swellings.* FNAC has excellent patient compliance, is simple and quick to perform in the out-patient department and is readily repeated.* Thyroid conditions that may be diagnosed by FNAC include colloid nodules, thyroiditis, papillary carcinoma, medullary carcinoma, anaplastic carcinoma and lymphoma.* FNAC cannot distinguish between a benign follicular adenoma and follicular carcinoma, as this distinction is dependent not on cytology but on histological criteria, which include capsular and vascular invasion.