Papillary thyroid carcinoma (PTC) is the most common thyroid carcinoma and is derived from
thyroid follicular cells. In contrast, medullary thyroid carcinoma (MTC) is rare and originates
from the parafollicular C-cells. Synchronous occurrence of these two carcinomas is uncommon and
occurs as either discrete lesions or as a mixed lesion. The current case report describes a 50-year-old
woman with synchronous multiple discrete MTC and PTC with lymph nodes metastasis. Pathologists
and treating physicians should be aware of the synchronous coexistence of these entities to avoid
possible misdiagnosis.