Bethesda Category II Results Are NEGATIVE for Malignancy
Your thyroid nodule cytology results classified as Bethesda Category II represent BENIGN (negative) findings with an extremely low risk of malignancy, typically 1-3%. 1
Understanding Bethesda Category II Classification
Bethesda Category II is the "benign" category in the standardized six-category Bethesda System for Reporting Thyroid Cytopathology, which stratifies thyroid nodules by malignancy risk to guide clinical management decisions 1
The specific findings in your report—hyperplastic nodule (left) and colloid nodule (right)—are classic benign patterns that fall into this category 2
Actual Malignancy Risk in Bethesda II Nodules
The false-negative rate for Bethesda II cytology is approximately 1.5-3.2%, meaning that in rare cases, malignancy can still be present despite benign cytology 3, 4, 5
A large retrospective study found incidental malignancy in only 1.53% (8/522) of surgically removed nodules that were initially classified as Bethesda II 5
Another study demonstrated malignancy rates of 3.2% in the pre-Bethesda period and 2.6% in the post-Bethesda period for nodules with initially benign cytology 4
Clinical Implications and Follow-Up
Immediate diagnostic intervention after benign cytologic diagnosis is generally not necessary, regardless of ultrasound features, though surveillance may be considered for highly suspicious ultrasound patterns 4
The presence of abundant colloid and follicular cells in macro/microfollicles (as described in your report) are reassuring cytological features consistent with benign nodular hyperplasia 2
Routine surveillance with ultrasound is typically recommended rather than repeat biopsy or surgery for Bethesda II nodules, unless high-risk clinical features develop (rapid growth, new suspicious lymph nodes, compressive symptoms) 1
Important Caveats
The pathology report appropriately notes that "there is an accepted false positive and negative rate in all cytologic diagnostic procedures," acknowledging the small but real possibility of sampling error 2
If you develop concerning clinical features (rapid nodule growth, voice changes, difficulty swallowing, palpable lymph nodes, or family history of thyroid cancer), repeat evaluation may be warranted despite the benign cytology 1
Ultrasound features matter: if your nodules have multiple highly suspicious ultrasound characteristics (microcalcifications, irregular margins, marked hypoechogenicity), closer surveillance may be appropriate even with Bethesda II cytology 4, 6