Clinical case seminar: Recombinant thyrotropin-induced orbital uptake of [111in-diethylenetriamine-pentacetic acid-D-phe1] octreotide in a patient with inactive graves' ophthalmopathy

Here we describe the case of a 60-yr-old nonsmoking woman with a history of Graves' disease associated with papillary thyroid carcinoma. After tumor removal, during the diagnostic follow-up for thyroid cancer, there was evidence of severe Graves' ophthalmopathy (GO) successfully treated with iv glucocorticoids. After this treatment, GO entered inactive status. The patient was then reevaluated for thyroid cancer with human recombinant TSH (rTSH). Orbital [¹¹¹In-diethylenetriamine-pentacetic acid (DTPA)-D-phe ¹]octreotide scan was also performed, and results were negative. Shortly after rTSH administration, a moderate and transient pain behind the eye globes at rest and during eye movement was reported, with an increase in the activity score but without further GO progression. Twenty-four hours after rTSH administration, the patient was submitted to a second [¹¹¹In-DTPA-D- Phe¹]-octreotide scan, revealing significant orbital uptake, likely related to rapid accumulation of activated lymphocytes with inflammatory cytokines or fibroblasts expressing somatostatin receptors in the orbital tissue or interstitial edema due to the inflammation process. At last follow-up performed after 1 yr, there was no evidence of active thyroid cancer or changes in GO severity and/or activity, and orbital [¹¹¹In-DTPA-D-phe ¹]octreotide uptake was negative. This case further supports the involvement of TSH receptor in the pathogenesis of GO. It also confirms the usefulness of orbital [¹¹¹In-DTPA-D-phe¹]octreotide scan to evaluate GO activity.