Massive pericardial effusion in an adult case of congenital hypothyroidism due to a sublingual thyroid.

Acquired hypothyroidism is known to cause cardiac tamponade. However, pericardial effusion in cretinism in adulthood has rarely been reported. A 27-year-old dwarfish woman suffering from congestive heart failure was diagnosed with congenital hypothyroidism due to the presence of a sublingual thyroid. The patient had never received thyroid therapy until the time of diagnosis at age 27. Despite the existence of massive pericardial effusion, the patient had hypertension. Her metabolic abnormality responded dramatically to L-thyroxin. Pericardial effusion disappeared one year after the initiation of medical treatment.