A Case Report of Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal Gammopathy, and Skin Changes (POEMS) Syndrome: A Diagnostic Iceberg.

POEMS syndrome (Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal plasma cell disorder, Skin changes) refers to a rare paraneoplastic entity linked to a plasma cell disorder, characterized by multiple systemic manifestations that must be studied together to establish a timely diagnosis. We report a case of a 60-year-old female who had been initially classified to have Guillain Barré syndrome for one year and seven months, receiving three cycles of immunoglobulin without a positive response. The clinical picture was characterized by painful paresthesias in four limbs and paraparesis, with the patient also developing distal cutaneous hyperpigmentation and multiple adenopathies. Neuroconduction studies revealed chronic sensorimotor axonal polyneuropathy and albumin-cytological dissociation was evidenced in the study of cerebrospinal fluid (CSF). In the subsequent evaluation, Lambda light chains and a lymph node biopsy compatible with Castleman's disease were found, and hence it was determined that the patient met the criteria for POEMS syndrome. This case report highlights the importance of incorporating other diagnostic perspectives when encountering patients with polyneuropathy of immunological origin who fail to respond to conventional therapies.