Abstract. For s > 0 given, we consider a planar domain Ω s with a rectifiable boundary but containing a cusp of degree s, and show that there is no homeomorphism f : R 2 → R 2 of finite distortion with exp(λK) ∈ L 1 loc (R 2 ) so that f (B) = Ω s when λ > 4/s and B is the unit disc. On the other hand, for λ < 2/s such an f exists. The critical value for λ remains open.