Abstract
Metastasis to the pituitary gland/sella turcica is an uncommon complication of thyroid cancer. Treating this condition is a challenge in the setting of pituitary insufficiency due to this lesion, and recombinant human thyroid-stimulating hormone (rhTSH) stimulation becomes critically essential. We present a rare case of an 82-year-old female patient with follicular carcinoma of the thyroid with metastasis to the sella turcica in addition to multiple skeletal and lung metastases. MRI of the brain showed a hypointense suprasellar lesion on T 1 weighted images. The thyroid-stimulating hormone level remained persistently low even 4 weeks after thyroidectomy. A whole-body pertechnetate scan could not localize any abnormal tracer uptake and radioactive iodine uptake was also persistently low. The patient did not have symptoms related to pituitary involvement but TSH and early morning adrenocorticotrophic hormone levels were low. After thorough discussion with the neurosurgeon and radiotherapist, it was decided to start the patient on high-dose radioiodine treatment. Persistently low TSH level was a concern for starting radioiodine therapy. In view of this clinical context, rhTSH stimulation was used to achieve adequate TSH levels prior to radioiodine therapy. Subsequently, the patient was treated with 3.7 GBq (100 mci) of high-dose radioiodine. A post-therapy scan demonstrated radioiodine concentration in the thyroid bed remnant, multiple skeletal lesions and the sellar region. Thus, the use of rhTSH was critical in the management of this patient. It helped in radioiodine treatment by stimulating radioiodine uptake in the remnant and at the metastatic sites.
Highlights
The patient was referred to the department of nuclear medicine for further management
Morning (4 am) adrenocorticotrophic hormone (ACTH) was < 5 pg ml–1 (10–60 pg ml–1) and cortisol was 1.16 mg ml–1 (4.3–22.4 mg ml–1). This reconfirmed the diagnosis of pituitary insufficiency due to sellar metastasis with low iodine and pertechnetate uptake owing to the low thyroid-stimulating hormone (TSH) level
We report a rare case of sellar metastasis from follicular carcinoma without cranial nerve involvement and with partial pituitary insufficiency
Summary
The MRI and 18F-FDG PET-CT findings pointed toward the possibility of pituitary insufficiency owing to sellar metastasis resulting in low TSH. Morning (4 am) ACTH was < 5 pg ml–1 (10–60 pg ml–1) and cortisol was 1.16 mg ml–1 (4.3–22.4 mg ml–1) This reconfirmed the diagnosis of pituitary insufficiency due to sellar metastasis with low iodine and pertechnetate uptake owing to the low TSH level. After two rhTSH injections (0.9 mg on two consecutive days), the patient’s TSH levels went up to 664 mIU ml–1 She was subsequently treated with high-dose radioiodine of 3.7 GBq (100 mci). A post-therapy scan (Figure 4) revealed an intensely iodine-avid remnant in the thyroid bed, multiple skeletal metastasis and faint uptake in the sellar region. An endocrinologist’s opinion was sought for further management of the hypopituitarism. 6 months post radioiodine treatment, the patient was clinically stable and an early second radioiodine therapy was planned under rhTSH stimulation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
