Microinvasive follicular thyroid carcinoma detected by fine needle aspiration skeletal metastases. A case report

BACKGROUND

Fine needle aspiration biopsy (FNAB) for the cytologic diagnosis of bone metastatic lesions is often useful for locating the primary tumor and choosing treatment. The cytologic picture of follicular carcinoma most commonly resembles normal thyroid but may exhibit variable anaplasia. Marginal vacuoles, also known as fire flare-like vacuoles and "flame cells," have been found mainly in toxic goiter but also in some non-toxic goiter. The presence of marginal vacuoles of FNAB of metastatic follicular carcinoma was first reported by Pitts et al in 1988.

CASE

A 77-year-old male presented with multiple lytic lesions involving the vertebral bones and ribbons. FNAB of vertebral bone showed tumor cell clusters in a follicular pattern with peripherically situated, pink-stained vacuoles on May-Grünwald-Giemsa stain.

CONCLUSION

FNAB is useful in the diagnosis of metastatic thyroid neoplasms. The recognition of marginal vacuoles, along with the appropriate cytologic findings, should provide morphologic clues leading to a suspicion of thyroid neoplasm metastasis in FNAB.

Fine needle aspiration biopsy in the diagnosis of thyroid cancer and thyroid disease

Fine needle aspiration biopsy (FNAB) performed for diffuse and nodular goiter in the past 5 years, was evaluated in 1399 cases. Surgery was performed on the basis of FNAB cytologic diagnosis that was positive or suggestive of malignancy and/or a suggestive clinical history. Surgery also was performed in cases of cold nodules with negative FNAB results that did not respond to 6 months of suppressive thyroxine therapy. A correlation of cytologic findings with histologic findings was possible in 415 patients who underwent surgery: the evaluation of FNAB results yielded better results when suspicious cytologic findings were considered to be positive (2.4% false-negative, 86.3% sensitivity) rather than negative (6.5% and 65.7%, respectively). FNAB has become a useful procedure in the study and diagnosis of thyroid diseases. It is a simple, rapid diagnostic procedure that may be used to expedite the management of malignant lesions.