Thyroid Mass Evaluation

Differential Diagnoses and Risk Factors

The vast majority (95%) of thyroid nodules are benign, with only 5% representing malignancy, making careful differentiation essential for appropriate management 1, 2
Papillary thyroid carcinoma accounts for 60-80% of detected thyroid cancers, particularly micropapillary (<1 cm) with excellent prognosis 1, 2
Follicular thyroid carcinoma cannot be distinguished from follicular adenoma by cytology alone 1
Medullary thyroid carcinoma represents 5-7% of thyroid cancers, arises from calcitonin-producing C cells 1, 2
A history of head and neck irradiation is the strongest risk factor for thyroid malignancy 1, 2, 3
A positive family history of thyroid cancer, particularly medullary thyroid carcinoma in MEN syndromes, increases malignancy risk 1, 2, 3
The presence of cervical lymphadenopathy is highly suspicious for malignancy, particularly papillary carcinoma 1, 2, 3

High-risk historical features, such as history of head and neck irradiation and positive family history of thyroid cancer, significantly increase malignancy risk and mandate evaluation even for nodules <1 cm 1, 2, 3
Associated symptoms, such as hoarseness, dysphagia, dyspnea or stridor, and pain, can indicate malignancy or other significant conditions 3