The authors present a case of a 36 years old woman applied to them for a follow up of sponge kidney disease and in whom they discovered a primary hyperparathyroidism. Further investigations discovered a medullary thyroid carcinoma. So this patient present multiple endocrine neoplasia (MEN) type 2A confirmed by microscopic and genetic analysis. This observation enlarged the discussion upon the nature of the relationship between kidney disease and primary hyperparathyroidism. Elsewhere it recommended to check systematically genetic markers of MEN type 2A if there is an association with sponge kidney disease and primary hyperparathyroidism.