Kocher-Debré-Sémélaigne syndrome with pericardial effusion

Kocher-Debré-Sémélaigne syndrome (KDSS) is a rare association of muscular pseudohypertrophy and hypothyroidism in children. We report an 11-year-old female child with hypothyroidism and limb muscle pseudohypertrophy with pericardial effusion. The patient presented with hypertrichosis only. She had dull facies and marked hypertrophy of both calves and cervical muscles. Pericardial effusion was confirmed on investigations. Muscle pseudohypertrophy was a striking feature, and hypothyroidism was confirmed on thyroid studies. Pericardial effusion is known in hypothyroidism but has been very rarely reported with KDSS.