Follicular neoplasms of the thyroid: Predictors of malignancy?

Follicular neoplasms of the thyroid present a therapeutic challenge. Initia l limited thyroidectomy may result in some patients requiring completion th yroidectomy for malignancy. In the current study we examined age, gender, r ace, time from nodule discovery to operation in months, history of radiatio n exposure, tumor size (cm), and cell type in patients with follicular neop lasms identified at the time of thyroidectomy in two socioeconomically dive rse settings from 1993 through 2000 to identify possible factors associated with a greater chance of malignancy. Of 36 follicular lesions identified i n 35 patients seven (19%) were malignant on permanent section. Hurthle cell histology was present in six of 36 lesions. Mean age of patients with beni gn lesions was 47 +/- 13 versus 50 +/- 15 in malignant cases (P>0.05). Beni gn lesions measured 2.6 +/-1.2 cm versus 3.1 +/-1.7 cm in malignant (P>0.05 ). Other factors found not to be significant included gender and time nodul e was present (12.8 +/- 19 months benign vs 11.8 +/- 20 months malignant) ( P>0.05). Hurthle cell histology was associated with a 50 per cent malignanc y rate (three of six) versus 13 per cent (four of 30) with non-Hurthle cell histology (P<0.05). Two patients with exposure to radiation fallout had ma lignancies in lesions of one and 2 cm (P<0.05). Patients from a socioeconom ically disadvantaged setting had a malignancy rate of 50 per cent (six of 1 2) compared with a malignancy rate of 3 percent (one of 24) from a socioeco nomically affluent population (P<0.05). In conclusion Hurthle cell histolog y and exposure to radiation fallout were associated with significantly high er rates of malignancy in follicular neoplasms and should be taken into acc ount when deciding on the initial extent of thyroidectomy. The difference i n malignancy rates observed between socioeconomic settings while significan t requires further investigation.