Apparently benign oncocytic thyroid carcinoma

Oncocytic thyroid neoplasms are a variant of follicular tumours and can either be benign or malignant. However, difficulty in distinguishing benign from malignant oncocytic follicular tumors has been a matter of long-lasting debate.

Boronat et al. report on a case who had undergone total thyroidectomy for goitre and after 9 years, a striking elevation of serum thyroglobulin suggesting hidden metastatic disease was detected. A second empirical dose of 131I was administered. Two years later, whole body and FDG-PET scans showed a well-delimited focal uptake in the right femur. A bone biopsy of the lesion demonstrated metastasis of follicular thyroid carcinoma. Retrospective revision of the histological slides from the primary tumour did not reveal malignancy.

The case shows that distinguishing benign from malignant oncocytic follicular neoplasms remains difficult. The authors suggest that it is still prudent to recommend a very long period of surveillance for large solid non-malignant-appearing oncocytic tumours.

Read the full article at Boronat et al (2013) Endocrinology, Diabetes and Metabolism Case Reports, 9 2013, EDM130051, 10.1530/EDM-13-0051.