Coexistence of medullary thyroid cancer with Graves-Basedow disease

Paz-Ibarra J.; Fuentes-Mendoza J.M.; Gonzales-Valdivieso R.; Somocurcio-Peralta J.; Concepción-Zavaleta M.J. · Anales de la Facultad de Medicina (2025) · DOI: 10.15381/anales.v86i3.30566

Resumen

We present the case of a 54-year-old male with a two-month history of thyrotoxicosis, in whom a 1.5 cm thyroid nodule was identified, along with suppressed TSH, elevated free T4, positive antithyroid antibodies, and increased calcitonin levels. Thyroid scintigraphy showed a diffusely hyperfunctioning goiter, and biopsy confirmed medullary thyroid carcinoma (MTC) coexisting with Graves' disease (GD). The patient underwent total thyroidectomy with central neck dissection and was started on levothyroxine, with no recurrence to date. This case is unique due to the rare coexistence of GD and MTC—two entities with distinct pathophysiologies—and underscores the importance of comprehensive evaluation in the presence of atypical findings. It contributes to the literature by highlighting the need for considering alternative diagnoses even in seemingly straightforward clinical scenarios and reinforces the value of early detection in improving MTC prognosis.

Instituciones: Universidad Nacional Mayor de San Marcos; Universidad Científica del Sur