Fine-needle aspirate

Introduction

• Provides cells from skin or internal organs for microscopic examination.
• Aid in diagnosis of etiology of superficial masses and enlarged lymph nodes by cytologic evaluation.

Uses

• Diagnosis of lymphadenopathy.
• Evaluation of superficial masses.
• Evaluation of intracavity masses.

Advantages

• Rapid method of diagnosis.
• Simple - requires minimal equipment.
• Can be performed on conscious unsedated patient.
• Often yields definitive diagnosis.

Disadvantages

• Aspiration of intracavity masses needs to be guided by ultrasound .

Requirements

Materials required

Minimum consumables

• 1-1.5 inch, 21G needle.
• 10 ml syringe.
• Glass slides.

Sequelae

Reasons for treatment failure

• Mass may be too advanced in disease to yield evidence of active pathology.
• Sample of atypical area of mass or lesion.
• Inadequate suction applied.
• Maintenance of suction during needle withdrawal could have pulled specimen into syringe.
• Crush artifact can complicate interpretation (esp. lymph node aspirates).

Sources

Publications

• McCullough S et al(1999) Collection and interpretation of respiratory cytology. Clin Tech Small Anim Pract 14 , (4) 220-6.
• Valli V E O (1988) Techniques in veterinary cytopathology. Sem Vet Med Surg 3 , 85-93.