A team of researchers presented a case study of a patient with aggressive medullary thyroid cancer (MTC) as an initial presentation and concluded that choroidal metastasis of MTC is both extraordinarily rare and difficult to diagnose, according to a study published in the International Journal of Surgery Case Reports.
MTC is known to be an aggressive tumor, with common metastasis sites being the lymph nodes, bones, and lungs. “About 70% of MTC patients presenting with a palpable thyroid nodule have cervical metastases and 10% have distant metastases,” the research team wrote.
The choroid remains a rare location of MTC metastasis and is usually described in patients in which metastases to the breast, lung, or prostate have already occurred.
The researchers described a 38-year-old male who presented with a sudden onset of a painless decrease in vision of the right eye of 3 weeks. Initial examinations revealed retinal fluids and enlarged neck lymph nodes.
“Upon physical examination, visual acuity was counting fingers 1 m in the right eye and 6/6 in the left eye. Unaided fundus (dilated) cup-to-disc ratio (CDR) of the right eye was 0.6, with a healthy neuroretinal rim, but with parafoveal exudative retinal detachment. CDR of the left eye was 0.9, with normal macula, flat retina, and normal periphery,” the researchers wrote.
Further retinal examination revealed choroidal mass and retinal fluid, which was deemed to be most likely a metastatic choroid lesion. Further physical examinations revealed left-sided neck lymph nodes (20 x 20 nm) that were mobile, and not tender or fluctuant. An enlarged left lobe of the thyroid gland was observed.
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The research team conducted blood examinations, which revealed “high calcitonin levels (>585.200 pmol/L), CEA (503.0 μg/L), ACTH (68.6 pg/mL), cortisol (639.0 nmol/L), and prolactin levels (682 mIU/L),” they said. An ultrasound of the neck revealed a well-defined heterogeneous lobulated lesion in the mid to lower pole (42.4 × 20.8 × 26.2 mm), with internal vascularity. Enlarged neck lymph nodes with hypervascularity were also observed in the left neck regions.
Ultrasound-guided fine-needle aspiration of the thyroid tested positive for left thyroid nodule malignancy, with cytomorphologic features suggestive of MTC. Further imaging investigations (computerized tomography scans of the neck, lung, and abdomen; as well as magnetic resonance imaging scans of the head and orbit with contrast) revealed metastasis to the lung, bone, brain, pituitary, liver, and mediastinum.
The patient underwent total thyroidectomy and left neck dissection, as well as stereotactic radiosurgery for the right orbit and pituitary. The patient also received selpercatinib, an anti-RET therapy. The management strategy prescribed by the medical team demonstrated improved clinical outcomes: at the 5-month follow-up point, there was a notable drop in CEA from 888 μg/L to 164 μg/L and calcitonin from >585.2 pmol/L to 354 pmol/L.
Choroidal metastasis of MTC is rare, and to reach an early diagnosis means that “surgeons need to maintain a high index of suspicion when ocular symptoms accompany a neck mass or thyroid-related symptoms,” the authors concluded.
Al Hassan MS, El Ansari W, Alater A, et al. Choroidal metastasis as initial presentation of aggressive medullary thyroid carcinoma with widespread mediastinal, brain, pituitary, bone, lung, and liver metastasis: case report and literature review. Int J Surg Case Rep. Published online September 16, 2021. doi:10.1016/j.ijscr.2021.106419