AbstractWe refine the analysis, initiated in [3], [4] of the blow up phenomenon for the following two dimensional uniformly elliptic Liouville type problem in divergence form:We provide a partial generalization of a result of Y.Y. Li [18] to the case A ≠ I. To this end, in the same spirit of [2], we obtain a sharp pointwise estimate for simple blow up sequences. Moreover, we prove that if {p(∆detA)(pj) = 0, ∀ j = 1, ...,N.This characterization of the blow up set yields an improvement of the a priori estimates already established in [3].