Unusual Case of Papillary Thyroid Carcinoma with Choroidal Metastasis

Background: The choroid is a rare site of thyroid cancer metastases, and has been described in patients with evidence of advanced breast, lung, and prostate carcinomas. To the authors' knowledge, only seven reported cases exist with choroidal metastasis secondary to papillary thyroid carcinoma (PTC). This study describes an additional patient with metastatic PTC with simultaneous appearance of choroidal mass and cutaneous deposits while on systemic therapy with a tyrosine kinase inhibitor (TKI). These infrequent sites of metastasis are typically associated with a dismal prognosis following the diagnoses. However, this patient has not shown evidence of choroid or cutaneous recurrence one year following local targeted and systemic therapy. Patient findings: The case is presented of a 70-year-old male with widely metastatic PTC to the lymph nodes, lung, and mediastinum who was found to have choroidal metastasis six years after his initial diagnosis. Summary: The patient was asymptomatic and was found to have an incidental right choroidal mass on routine ophthalmology exam. Magnetic resonance imaging of the orbit revealed an isolated right choroid lesion suspicious for melanoma or metastasis. Concurrent to this discovery, he was noted to have progression of the lung and mediastinal disease along with new dermal lesions on the chest wall suspicious for dermal metastasis. Both the choroid and dermal metastases occurred while being on a TKI. Given his previous history of male breast carcinoma, a biopsy of the choroid was performed, which confirmed PTC. The patient developed endophthalmitis and subsequently underwent enucleation of the right eye. The choroid mass was completely excised, measured 3.5mmx9.5mm with negative margins, and histopathology was consistent with metastatic PTC. Pulmonary, mediastinal, and cutaneous lesions regressed after external beam radiation therapy, following which systemic therapy was changed to a different multikinase inhibitor. Conclusion: A rare and unique case is reported of choroidal metastasis from PTC that presented with concurrent new dermal metastasis in addition to lung and mediastinal lymph node progression. Furthermore, the patient developed choroid and dermal lesions while on a TKI and remained stable without recurrence in these regions after switching to an alternate multikinase inhibitor.