Automatic cell nuclei detection is a real challenge in medical imagery. The Marked Point Process (MPP) is one of the most promising scalable and paralellizable method. To handle large histopathology images, the algorithm has to be distributed. A new parallelization paradigm called Ordered Read-Write Locks (ORWL) is presented as a possible solution for solving some of the unwanted side effects of the distribution, namely an imprecision of the results on the internal boundaries of partitioned images. This solution extends a parallel version of MPP that has reached good speedups on GPU cards, but was not scaling to complete images as they appear in practical data.