POEMS syndrome with atypical presentation: A rare case.

POEMS is an uncommon paraneoplastic plasma cell disorder known with the expansion of polyneuropathy, organomegaly, endocrine abnormalities, M-band, and skin changes. We report a patient presenting with monoarthritis and weight loss for 5 months, who was treated empirically for tuberculous arthritis and later developed debilitating axonal polyneuropathy due to delayed diagnosis. POEMS/Plasma cell dyscrasias rarely involve joints, and this case highlights this unique presentation of POEMS syndrome. Bone biopsy from the affected joint revealed the diagnosis. Chronic large-joint monoarthritis with systemic symptoms, mimicking tuberculous arthritis, and polyneuropathy is a unique combination-so clinicians should consider an underlying plasma cell dyscrasia/POEMS to avoid delayed diagnosis.