Wireless Body Area Sensor Network (WBAN) has emerged as special type of wireless sensor networks. This emerging networking technology has applications in healthcare, sports & fitness, activity monitoring and disability assistance. Most of the work in literature in WBAN focuses on MAC and Physical layer. In contrast to this, in this paper, we present a study of self-organized routing (network layer issue). In this paper, we first highlight the routing issues and challenges in multi hop WBAN. We then review and classify the existing WBAN routing protocols from the literature, including self-organized routing. In addition we compare and analyse the proposed protocols based on certain key parameters. Finally, we have performed a simulation based case study to analyse the requirements and necessities of employing self-organizing in WBAN.