Diagnosis: Benign Thyroid Nodule (Bethesda Category II)
This FNA result showing abundant colloid with honeycomb sheets, clusters, and small delicate follicular epithelial cells is diagnostic of a benign thyroid nodule—specifically a colloid goiter, nodular goiter, or hyperplastic/adenomatoid nodule—and does not require surgical intervention. 1
Cytologic Classification
The described cytologic features—abundant colloid admixed with honeycomb sheets and small, delicate follicular epithelial cells—are classic findings that place this specimen in Bethesda Category II (Benign) according to the 2017 Bethesda System for Reporting Thyroid Cytopathology 1
The presence of abundant colloid is the key distinguishing feature that indicates a benign process rather than a follicular neoplasm, as microfollicular lesions with malignant potential characteristically show scanty or absent colloid 2
The honeycomb sheet pattern with regular spacing of follicular cells further supports a benign diagnosis, as microfollicular carcinomas typically demonstrate irregular cell arrangements and crowding within groups 2
Management Recommendations
The appropriate management is clinical surveillance without surgery. 1
Initial Management Steps:
Measure serum TSH level to assess thyroid function, as this is part of standard evaluation for all thyroid nodules 3, 4
Perform or review neck ultrasound to document nodule size and ultrasound characteristics for baseline comparison 3
Reassure the patient that this is a benign finding with very low malignancy risk (typically <3% for Bethesda Category II) 5
Surveillance Protocol:
Follow with repeat ultrasound at 12-24 month intervals to monitor for nodule growth or development of suspicious ultrasound features 4
Repeat FNA is indicated only if the nodule demonstrates significant growth (>20% increase in at least two dimensions with minimum 2mm increase) or develops new suspicious ultrasound features such as microcalcifications, irregular borders, or marked hypoechogenicity 4
Indefinite observation without intervention is appropriate if the nodule remains stable in size and characteristics 4
Critical Pitfalls to Avoid
Do not proceed to surgery based solely on nodule size or patient anxiety. The cytologic diagnosis of benign disease should guide management, and surgery is not indicated for benign cytology in the absence of compressive symptoms or cosmetic concerns 1
Do not ignore worrisome clinical findings if present. While this FNA is reassuring, the NCCN explicitly warns that false-negative results can occur, and a benign FNA should not override clinical concerns in patients with high-risk features such as rapid nodule growth, vocal cord paralysis, fixed nodule, family history of thyroid cancer, or history of head/neck radiation 6, 4
Ensure expert pathology review if any clinical-cytologic discordance exists. FNA sensitivity varies by cancer type, and medullary carcinoma in particular can be missed on routine cytology 6
Do not confuse this benign pattern with follicular neoplasm. The abundant colloid and regular honeycomb architecture clearly distinguish this from Bethesda Category IV (follicular neoplasm), which would show cellular aspirates with scant colloid and microfollicular architecture requiring surgical excision 1, 2
When to Reconsider the Diagnosis
Repeat FNA should be performed if:
The nodule grows significantly on surveillance ultrasound (>20% increase in two dimensions with minimum 2mm growth) 4
New suspicious ultrasound features develop (microcalcifications, irregular borders, marked hypoechogenicity, taller-than-wide shape, or extrathyroidal extension) 4
High-risk clinical features emerge (rapid growth, compressive symptoms, vocal cord changes, new lymphadenopathy) 4