Background.- Medullary thyroid carcinoma usually presents with palpable cervical lymphadenopathy, rapidly arising neck mass and local pain. Less frequently, dysphagia, dyspnea and dysphenia can be seen as a result of local invasion. However, especially in familial cases (MEN 2A, MEN 2B and nonMEN), chronic diarrhea can develop as the only symptom. Observation.- In the present study, we present a 25 year-old male patient with distant metastasis of medullary thyroid carcinoma. The diagnosis was confirmed after liver biopsy taken during diagnostic laparoscopy.* Anahtar Kelimeler: Medüller tiroid karsinomu, metastaz, ishal* Key words: Medullary thyroid carcinoma, metastasis diarrhea