This narrative review delves into the complexities of anorexia nervosa (AN), focusing on its unique manifestations within diverse contexts, particularly in cancer patients. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic approach was employed via electronic databases such as PubMed, Scopus, and Google Scholar. AN has been explored in the context of cancer-related anorexia‒cachexia syndrome, aging, and autoimmune disorders. The diagnostic criteria from the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) are outlined, emphasizing severe disturbances in eating behavior and self-imposed starvation. A thorough examination of the physiological, psychological, and social aspects of AN provides a comprehensive understanding of its multifactorial nature. This review outlines diverse management strategies for AN, encompassing nutritional rehabilitation, psychotherapeutic interventions, and potential pharmacological treatments. Various studies have summarized emerging signaling pathways in cancer-related AN, the bidirectional associations between AN and autoimmune disorders, and potential therapeutic modalities such as acupuncture. Emphasis is placed on the importance of family support, psychoeducation, and early intervention in cancer patients with AN, highlighting the integral role of a comprehensive approach in improving outcomes. In conclusion, this narrative review offers valuable insights into the intricate nature of AN, providing a basis for future research and clinical efforts to refine targeted interventions, particularly within the context of cancer patients. The article provides a broad overview of AN, serving as a resource for those interested in understanding its diverse manifestations.