Toxic Hot Nodule and Cancer?

Thyroid Case of the Week.

40 Y/O female, was noted to have suppressed TSH ( <0.01 ), during an infertility evaluation.
Asymptomatic. Has had a suppressed TSH for 2 years.
Father: Hyperthyroid on Antithyroid drugs
Mother: Hypothyroid on thyroid hormone.
Infertility for 2 1/2 years
Ultrasound: 1 cm mass is noted in her left lobe. Right normal normal.
Thyroid scan: Hot left lobe with suppressed right lobe.
A diagnosis of Autonomous hot nodule with subclinical hyperthyroidism was made.
Normal uptakes at 6/24 hours.
FT4,FT3, TPO, TSI all normal.
Because of her age, and her desire to get pregnant soon, she was offered surgery, instead of radioiodine.
Surgery :left lobectomy.
Pathology Papillary Thyroid cancer, with 1 node positive.
Post surgery Thyroglobulin 10.3 This is consistent with output from a single remnant right lobe.
Second surgery: Right lobectomy: Normal thyroid, but 1/3 nodes positive.

Comments.
I have never seen a hot nodule produced by a papillary thyroid cancer.
Follicular cancers if they are > 4 cm may make one toxic with suppressed TSH.
I do not understand this case. I can only speculate that the cancer was near, but not
the exact area that produced increased iodine uptake.The patient has a normal TSH post lobe removal TSH 1.4. The cancer is being treated by thyroid hormone suppression, and follow up with ultrasound, and Thyroglobulin. If there is persistent TG in 3-6 months, Radioiodine will be used. She still wants to get pregnant ASAP.

Dr.G
www.thyroid.com