Studies of exclusive processes at HERA allowed to determine the single parton small x transverse structure of the nucleon, giving important constrains on the pp collision dynamics at the LHC. In particular this allows to explain the observed saturation of the underlying multiplicities in events with a jet trigger. Theoretical developments in the studies of multiparton correlations are summarized which suggest the presence of significant parton - parton transverse correlations already at a low virtuality scale. It is suggested that large fluctuations in the shape of the nucleon wave function as well as in the gluon densities occur and a method to probe these fluctuations is suggested. A possible relation of these effects to the structure of the high multiplicity events reported by CMS is also outlined.