Isolated thyroid metastasis from benign phyllodes tumour

Abstract

We present a rare and interesting case of a 35-year-old woman who initially underwent an uneventful wide excision for a 13 cm left benign phyllodes tumour. She then noted a slowly growing left thyroid nodule 8 months postsurgery which on thyroidectomy 4 years later was shown to be a 6.9cm isolated thyroid metastasis from the phyllodes tumour. As this may be the first reported such case in the literature, implications on histological classification, predictive factors for disease progression, mechanisms of metastasis, and evaluation, management and surveillance of benign phyllodes tumours and thyroid nodule/s with a history of phyllodes tumour can thus be significantly impacted.

Keywords: breast cancer; breast surgery; oncology.

Figure 1

Benign phyllodes tumour with mild cellularity and absent to minimal stromal atypia (400×, H&E).

Figure 2

Phyllodes tumour infiltrating non-neoplastic thyroid. Arrowhead pointing to thyroid tissue. Long arrow pointing to tumour with marked cellularity and stromal overgrowth. Short block arrow pointing to tumour with mild cellularity (100×, H&E).

Figure 3

TTF-1 positive (+) thyroid tissue infiltrated by TTF-1 negative (−) tumour. TTF-1, thyroid transcription factor 1 (100 ×, Immunohistochemistry horseradish peroxidase method).