The rapid development of the Internet of Medical Things (IoMT) technology has resulted in various advances in the smart healthcare field; it improves healthcare systems to offer more complicated real-time services and provides an efficient patient motioning system. However, despite the brilliant side of IoMT, several concerns continue to undercut its adoption. In fact, collecting, transmitting, storing, and using data in IoMT applications raises issues regarding privacy and data protection, especially with the multitude of stakeholders involved during the whole data life cycle. Motivated from these facts, this article is devoted to perform a Systematic Literature Review (SLR) of privacy-preserving solutions used in the smart healthcare ecosystem. The recent research papers disseminated between 2017 and 2021 are selected from multiple databases and a standardized SLR method is conducted. A total of 100 papers were reviewed and a critical analysis was conducted on the selected papers. Moreover, this review study attempts to highlight the limitation of the current approaches and aims to find possible solutions to them. Thus, a detailed analysis was carried out on the selected papers in terms of the privacy techniques they deployed, the data life cycle phase they addressed, the stakeholders needs they met, and the privacy principles they covered according to privacy laws and regulations. Finally, we summarize our results showing privacy-preserving trends and identifying recommendations to involve privacy principles coverage in smart healthcare applications.