Poster Presentation ESA-SRB Conference 2015

Ms KJ is 52 years old lady who presented with 6 weeks of subscapular and thoracic back pain. CT identified an osteolytic lesion and soft tissue mass in the thoracic spine, and an incidental left lobe thyroid mass causing contralateral tracheal displacement. MRI showed impending cord compression, necessitating a T5 vertebrectomy. Metastatic follicular thyroid cancer was diagnosed on histopathology.

Her thyroid ultrasound showed a left lobe thyroid nodule without clear tracheal invasion or lymph node involvement. Non-contrast CT demonstrated a low density mass with calcific foci replacing the left lobe of the thyroid gland. Lung metastases were not seen on X-ray, and her repeat MRI showed lesions consistent with haemangiomas.

A total thyroidectomy with lymph node resection was performed. Her left lobe had a 30x30x28mm tumour, containing a mixture of well and poorly differentiated regions. The differentiated areas demonstrated a follicular pattern with colloid filled microfollicles lined by atypical follicular cells, staining positive for thyroglobulin; the poorly differentiated areas had solid pattern of sheets and cords of tumour cells in a desmoplastic stroma without follicles, with increased staining for cyclin D1 and P63. No malignancy was found nodally. She was diagnosed with stage IVC (T2N0M1) poorly differentiated insular variant of follicular carcinoma.

She was further treated with thyroxine withdrawal high dose radioactive iodine at 5300MBq. This reduced her thyroglobulin levels, although they remained elevated 3 months post (Fig.1). Combined PET and radioiodine scan (Fig.2) revealed new metabolically active but iodine inactive lesions in the liver and the right upper sternum, and a mildly iodine active but PET avid T5 vertebral body lesion. The spine was treated with radiotherapy, analgesia and dexamethasone. The liver lesion was confirmed to be a solitary metastasis on primovist MRI, which will be considered for surgical resection post radiotherapy.