Unilateral hypoplastic kidney and ureter associated with diverse mesonephric remnant hyperplasia.

Mesonephric remnants have been rarely reported in the genitourinary system and sometimes impose a diagnostic challenge both clinically and pathologically. We reported a case of mesonephric remnant hyperplasia with mixed acinar/tubular and epididymis/vas deferens-like morphologies occurring in the renal parenchyma of a unilateral hypoplastic kidney, which has not been previously described.