Uncertainty is a common experience within human cancer. For brain tumor patients, irregular symptom pattern and presentation may promote uncertainties about treatment response, prognosis, and life quality. We sought to identify the somatic symptom experience associated with primary and secondary brain tumors and the potential impact on illness-related uncertainty. An integrative literature search of Medline and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) was performed. Symptom data were excerpted into tables and reviewed critically against the broader uncertainty-focused oncology literature. Twenty-one studies investigated a diverse range of brain tumor symptoms that persist through the now-expanding, post-treatment survival. While symptoms such as fatigue were common, antecedents and patterns were poorly characterized and inconsistent between and within categories of tumor. Symptom investigation is an emerging and rapidly developing area of neuro-oncology. The extent to which symptoms are familiar, predictable, and understandable can mitigate uncertainty. The unstable nature of symptoms across the trajectory of a brain tumor may be a significant corollary to illness-related uncertainty. Because the majority of brain tumor patients cannot be cured of their cancer, understanding the symptom expanse and potential to promote uncertainty could inform alternative nursing strategies to reduce anxiety and distress, and to preserve life quality where cure is often unattainable.