Plasma cell myeloma with an evolving diagnostic complexity: A case report.

Peripheral neuropathy is among the most prevalent neurological conditions; however, its etiology is frequently complex and varied, with a propensity for progression and recurrence. The present study describes a case of plasma cell myeloma featuring a protracted and complex diagnostic and therapeutic course, supported by extensive clinical, laboratory and imaging findings. The patient initially exhibited clinical features highly indicative of subacute combined degeneration and chronic inflammatory demyelinating polyneuropathy, which gradually progressed to manifestations of polyneuropathy, organomegaly, endocrine dysfunction, monoclonal plasma cell proliferation and skin changes syndrome. Ultimately, a biopsy confirmed a diagnosis of plasma cell myeloma. The patient has been followed up for 3.5 years since the final diagnosis. Owing to early diagnosis and timely comprehensive treatment, the patient can now independently manage their daily activities, and has markedly improved limb strength, with only minor residual sensory deficits. This case underscores the difficulties in diagnosing and treating plasma cell myeloma, given that early symptoms are similar to those of other condition.