RESUMO
RATIONALE: This article presents the case of a patient with recurrent chronic diarrhea and cachexia who was misdiagnosed, followed by a literature review to summarize the reasons for misdiagnosis of POEMS syndrome and the treatment strategies. PATIENT CONCERNS: The diagnosis and treatment of this patient suggest that with the improvement of M-protein detection levels, the diagnosis of patients with low M-protein levels, such as those with POEMS syndrome, has been greatly aided. DIAGNOSES: POEMS syndrome requires polyneuropathy and monoclonal plasma cell proliferation as mandatory diagnostic criteria. Therefore, patients presenting with polyneuropathy should routinely undergo M-protein testing and consider the possibility of POEMS syndrome. INTERVENTIONS: The patient, in this case, was treated primarily with relatively conservative immunomodulatory agents. OUTCOMES: During follow-up after treatment, the patient's diarrhea and malnutrition showed significant improvement. LESSONS SUBSECTIONS: POEMS syndrome has low clinical specificity and a high rate of misdiagnosis. However, once a definitive diagnosis is made, the treatment outcome is favorable.