Hurthle cell neoplasm of the thyroid gland

A clinicopathological analysis and long-term follow up of 32 patients with Hurthle cell neoplasm (HCN) was undertaken to contrast the clinical and histological features between benign versus malignant HCN of thyroid and to examine the effect of treatment on the outcome.

This is a retrospective study of 32 patients with HCN who were identified out of an archival clinical/pathological/imaging database of 3752 thyroid cancer patients seen between 1976 and June 2006. All patients underwent thyroid surgery. Data for the non-surgical treatment along with follow up were also analysed.

Seventeen patients were classified as malignant HCN (MHCN) and 15 as benign HCN (BHCN). Among the MHCN, there were 11 women and 6 men, whereas among BHCN there were 14 women and 1 man. Three patients designated MHCN presented with metastases, one with pulmonary metastases and two others with skeletal metastases who developed lung metastases 9-19 months later. The mean tumour size was 4.43 +/- 0.66 cm for MHCN, and 2.57 +/- 0.32 cm for BHCN (P = 0.03). Multicentric tumour foci were evident in five cases (29%) of MHCN but none among the BHCN (P = 0.03). At neck exploration cervical lymph node dissection was carried out in nine MHCN patients with findings of tumour metastases in 33%. Postoperatively, three MHCN patients had no thyroid remnant on ultrasound and computed tomography of neck and undetectable serum thyroglobulin; these were considered to be in remission. Fourteen other MHCN patients with postoperative thyroid remnant and/or distant metastases received 131I treatment. Eight of these patients had negative whole-body scans after 131I treatment and undetectable thyroglobulin. Accordingly, 11 MHCN patients (64.7%) showed evidence of remission and 6 patients did not respond to 131I treatment. After a mean follow up of 35 months, all BHCN patients are alive with no evidence of disease. Of the MHCN, 11 (64.7%) were in remission and 35% had evidence of persistence/recurrence. One patient who had recurrence is dead. A lack of effectiveness of 131I therapy in two patients with distant metastases is an important finding.

Features of MHCN consisted of a large tumour size, unequivocal capsular and vascular invasion, multicentric tumour foci, metastatic lymph node deposits in one-third of patients and presence of distant metastasis in a few. Findings of dominant Hurthle cell cytology in a fine-needle aspiration biopsy from a thyroid nodule should prompt surgical resection of the lesion to assess malignancy.