## **Core Concept**
The patient's presentation of hoarseness of voice and a single enlarged painless lymph node in the left supraclavicular region is highly suggestive of a malignancy, particularly lung cancer or head and neck cancer. The supraclavicular lymph nodes are considered a Virchow's node, which is a significant clinical finding often associated with abdominal or thoracic malignancies.

## **Why the Correct Answer is Right**
The correct approach involves an immediate and thorough investigation to identify the primary source of the malignancy. Given the location of the lymph node and the symptom of hoarseness, which could indicate involvement or compression of the recurrent laryngeal nerve, a **Fine-Needle Aspiration Cytology (FNAC)** of the lymph node is the most appropriate next step. FNAC is a quick, minimally invasive procedure that can provide a cytological diagnosis, helping to guide further management.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While imaging like CT or MRI can be helpful in staging and identifying the primary tumor, they are not the immediate next step after finding a painless lymph node.
- **Option B:** A detailed history and physical examination are crucial but do not directly address the need for a tissue diagnosis.
- **Option D:** Though a biopsy can provide a definitive histopathological diagnosis, FNAC is generally preferred as the initial diagnostic tool due to its simplicity and lower risk of complications.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that a painless lymph node enlargement, especially in a specific location like the supraclavicular region, should raise a high suspicion for malignancy. The presence of hoarseness of voice along with this finding significantly points towards a possible lung or laryngeal cancer. Early and accurate diagnosis through FNAC or biopsy is critical for planning treatment.

## **Correct Answer:** . **Fine Needle Aspiration Cytology (FNAC)**