A 52-year-old man presents with a 3-month history of a painless swelling in the right parotid region. On examination, there is a firm, mobile mass approximately 2 cm in size. The overlying skin is normal. Which investigation is most appropriate to confirm the diagnosis and determine the nature of the lesion?

## Investigation of Choice for Salivary Gland Tumors **Key Point:** Ultrasound with fine-needle aspiration cytology (FNAC) is the gold standard first-line investigation for suspected salivary gland tumors. It combines morphological assessment with cytological diagnosis. ### Why Ultrasound + FNAC? 1. **Non-invasive yet diagnostic**: FNAC provides cytological confirmation without requiring open biopsy (which risks tumor spillage and facial nerve injury). 2. **High sensitivity and specificity**: When performed by experienced radiologists, FNAC has >90% accuracy for distinguishing benign from malignant lesions. 3. **Cost-effective**: Readily available, inexpensive, and can be repeated if needed. 4. **Real-time guidance**: Ultrasound provides real-time needle visualization, improving accuracy. 5. **No radiation exposure**: Unlike CT, making it safe for initial evaluation. ### Role of Other Investigations | Investigation | Role | Timing | |---|---|---| | **Ultrasound + FNAC** | First-line: morphology + cytology | Initial evaluation | | **CT/MRI** | Staging, assessing bone/soft tissue involvement, perineural spread | After diagnosis confirmed | | **Scintigraphy** | Functional assessment (rarely used in modern practice) | Not routine | **High-Yield:** The Bethesda classification for salivary gland cytology (Non-diagnostic, Benign, Atypia of undetermined significance, Suspicious for malignancy, Malignant) guides management after FNAC. **Clinical Pearl:** If FNAC is non-diagnostic or shows atypia, core needle biopsy (CNB) under ultrasound guidance is the next step—NOT open biopsy, which risks tumor seeding. ### Mnemonic: FNAC Advantages **SAFE** — Specific, Accurate, Fast, Economic.