The possibility to access healthcare fairly and equally among all the patients can be enhanced with the development of collaborative networks. To achieve their goals and exchange relevant information, they must be combined with a proper digital support. Several works dealing with this aspect can be found in literature; however, works defining a general methodological approach to design a digital solution for a collaborative network were not found. In addition to this, to assess the impact of a pathology network and its digital support, and ensure quality improvement as well as proper clinical outcomes, a suitable panel of key performance indicators (KPIs) should be designed. This paper describes a methodology to design a digital support of a collaborative pathology network, together with a set of KPIs to assess the impact of the pathology network and its digital solution. This approach was specifically applied for the Italian Rare Cancer Network in the context of the project “Italian Rare Cancer Network: Process monitoring and System Impact Assessment”.