Struma ovarii maligno no sospechado: diagnóstico citológico mediante punción aspirativa con aguja fina de lesión vertebral metastásica

Malignant struma ovarii is an exceptionally rare tumour which may metastasize, in the same way as other malignant tumours of thyroid origin. We report a case of a 56-year-old woman who presented with a pelvic mass and lung and bone lesions. To our knowledge this is the first case of malignant struma ovarii with bone metastases diagnosed by CT-guided FNA. The aim of this report is to emphasize the usefulness of immunocytochemistry, in particular TTF1 and thyroglobulin, in cytological samples in order to identify the epithelial cells and microfollicles as thyroid tissue. We also describe the correlation between the cytology and histology of this lesion.