Introduction: Dyshormonogenetic goiter is a genetically determined thyroid hyperplasia due to an enzyme defect in thyroid-hormone synthesis. Malignant transformation is one of the most serious complications, rarely reported in the literature.
Observation: We report a new case of a 13-year-old boy with goitrous hypothyroidism who consulted for a voluminous goiter. Total thyroidectomy was performed. Histopathological examination revealed multiple foci of papillary carcinoma with a lymph node metastasis.
Conclusion: Dyshormonogenetic goiter is a rare entity, representing one of the causes of congenital hypothyroidism. It is morphologically characterized by architectural and cellular pleomorphism that may mimic thyroid malignancy and cause difficulties in differential diagnosis.