What does a pathology report showing bland-looking follicular cells, oncocytes (Hurthle cells), and colloid consistent with follicular nodular disease from a Fine Needle Aspiration (FNA) biopsy mean?

Understanding Follicular Nodular Disease with Hurthle Cells on FNA

Your FNA pathology report showing bland-looking follicular cells, oncocytes (Hurthle cells), and colloid is consistent with a benign follicular nodular disease, which typically has an excellent prognosis and low risk of malignancy.

What This Pathology Report Means

Breakdown of Key Components:

• Bland-looking follicular cells: These are normal-appearing thyroid cells without concerning features that would suggest cancer
• Oncocytes/Hurthle cells: These are large cells with abundant granular cytoplasm that can appear in both benign and malignant conditions
• Colloid: This is the protein material normally found in thyroid follicles; its presence typically suggests a benign process
• Follicular nodular disease: A general term describing nodular enlargement of the thyroid with follicular architecture

Classification in the Bethesda System:

This finding likely falls into Bethesda Category II (benign) or possibly Category III (atypia of undetermined significance/follicular lesion of undetermined significance) 1. The Bethesda System is used to categorize FNA results to guide management.

Clinical Significance

Risk of Malignancy:

• The presence of Hurthle cells alone does not increase the risk of malignancy in most Bethesda categories 2
• When Hurthle cells are present but not predominant (less than 75% of cells), the risk of malignancy is actually lower than in FNAs without Hurthle cells 2
• Only when Hurthle cells are the predominant cell type (>75% of cells) in a specimen otherwise classified as benign is there an increased risk of malignancy 2

Common Conditions Associated with This Finding:

1. Nodular goiter/hyperplastic nodule (most common)
2. Hashimoto's thyroiditis
3. Follicular adenoma (benign tumor)
4. Hurthle cell adenoma (benign tumor)
5. Less commonly, follicular carcinoma or Hurthle cell carcinoma

Management Considerations

Follow-up Options:

1. Active surveillance with regular ultrasound monitoring if the nodule is:

   • Small (less than 3 cm)
   • Has benign ultrasound features
   • No concerning clinical symptoms 1, 3

2. Consider lobectomy for definitive diagnosis/treatment if:

   • Nodule is large (≥3 cm) - larger nodules have higher malignancy risk (28% vs 17% for smaller nodules) 4, 5
   • Nodule has suspicious ultrasound features (hypoechoic, solid composition)
   • Hard consistency on palpation 4
   • Patient preference for definitive diagnosis 1

Important Considerations:

• Hurthle cell neoplasms can sometimes mimic other conditions like medullary thyroid carcinoma on cytology 1
• Molecular testing is generally not recommended for Hurthle cell neoplasms as it may not perform well for these specific lesions 1
• The presence of colloid in your sample is reassuring, as abundant colloid is associated with benign conditions 6

Follow-up Recommendations

• Regular neck ultrasound monitoring (initially at 3-6 months, then annually if stable)
• Repeat thyroid function tests to ensure normal thyroid function
• Monitor for any changes in nodule size or development of new symptoms
• If the nodule grows significantly or develops suspicious features, reevaluation with repeat FNA or consideration of surgery may be warranted

Common Pitfalls to Avoid

1. Overtreatment: Most thyroid nodules with this pathology are benign and do not require aggressive intervention
2. Underestimation: Ignoring risk factors like large nodule size (≥3 cm), hard consistency, or suspicious ultrasound features
3. Misinterpretation: Assuming all Hurthle cells indicate cancer (they don't - they appear in many benign conditions)
4. Inadequate follow-up: Even benign nodules require appropriate monitoring over time

Remember that this pathology finding is generally reassuring, but appropriate follow-up is still important to ensure your continued good health.