# Case Report: POEMS syndrome secondary to multiple solitary plasmacytomas complicated by hypertriglyceridemia

## TL;DR

This case report describes a rare instance of POEMS syndrome diagnosed without detectable M-protein, highlighting the importance of considering the condition in atypical presentations.

## Contribution

The novelty lies in diagnosing POEMS syndrome without measurable M-protein, emphasizing the need for broader diagnostic awareness.

## Key findings

- POEMS syndrome was diagnosed in a patient without detectable M-protein through imaging and pathological evaluation.
- The patient showed clinical improvement after bortezomib-based chemotherapy.
- Severe hypertriglyceridemia and multisystem injury were key features in this atypical case.

## Abstract

Polyneuropathy, organomegaly, endocrinopathy, M protein, skin changes syndrome, encompassing polyneuropathy, organomegaly, endocrinopathy, M protein (Monoclonal Immunoglobulin), and skin changes, is a rare systemic disease often marked by diverse endocrine manifestations. Diagnosis typically relies on the detection of monoclonal protein; therefore, cases lacking measurable M-protein may be easily overlooked or misdiagnosed.

We describe a diagnostically challenging case involving a patient in their early fifties who presented with progressive limb numbness and weakness, skin hyperpigmentation, lower-extremity edema, hypothyroidism, and marked hypertriglyceridemia. Despite this multisystem involvement, repeated serum and bone marrow studies failed to demonstrate monoclonal protein. Subsequent imaging and pathological evaluation of the sacroiliac region revealed multiple solitary plasmacytomas with lambda light-chain restriction, which established the diagnosis of POEMS syndrome in the absence of detectable M-protein. The patient experienced notable clinical improvement following bortezomib-based chemotherapy.

This case illustrates that POEMS syndrome should be considered even when serum and bone marrow studies do not show monoclonal protein, particularly in the presence of severe hypertriglyceridemia and multisystem injury. Awareness of such atypical presentations is essential to prevent diagnostic delay and to ensure timely initiation of appropriate therapy.