Systemic Light Chain Amyloidosis Mimicking Rheumatic Disorders

Nail Amyloidoma: Two Case Reports of a New Entity

Introduction

Amyloidosis is a group of diseases characterized by extracellular deposits of abnormal insoluble proteins in different tissues. Amyloidoma is a localized tumoral deposit of amyloid in the absence of systemic amyloidosis, and it has been described in different anatomic sites. We report two cases of amyloidoma in the nail unit and provide insights into this recently described entity.

Case Presentation

Both cases presented as an asymptomatic, slowly growing nodule underneath the distal nail bed of a toe with associated onycholysis. Histopathology was characterized in both patients by the presence of deposits of Congo red-positive, homogeneous, amorphous, and eosinophilic material within the dermis and subcutaneous tissue admixed with aggregates of plasma cells. In both cases, an extensive workup excluded systemic amyloidosis. Treatment was based on local excision, and no local recurrence or progression to systemic amyloidosis was observed at 1 year of follow-up.

Conclusion

These are the first reports of amyloidomas of the nail unit. The clinical and histopathological presentations parallel those of an amyloidoma affecting the skin. Local excision seems to be an efficient treatment modality, but long-term follow-up is warranted in order to exclude recurrence, an associated marginal B-cell lymphoma, or progression to systemic amyloid L amyloidosis.

Raynaud's phenomenon and positive antinuclear antibodies as first manifestation of POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes): a case report

Background

POEMS syndrome is a rare paraneoplastic syndrome caused by plasma cell disorder almost always lambda restricted. Secondary Raynaud’s phenomenon is an overlooked skin manifestation of the disease even though it is present in twenty percent of patients. On POEMS syndrome have not been described positive antinuclear antibodies (ANA) and this could lead to a misdiagnosis of autoimmune disease, mainly systemic sclerosis.

Case presentation

A 47-year-old man presented with color changes on fingertips consistent with biphasic Raynaud’s phenomenon; an antinuclear antibody test was positive (at 1:320 titers in a speckled pattern) with normal nailfold capillaroscopy. Clinical features of systemic sclerosis were absent. Twenty-four months later, the patient presented symmetric sensorimotor demyelinating polyneuropathy, and he was diagnosed with Guillain–Barre syndrome; treatment with intravenous gammaglobulin had an incomplete response. Raynaud’s phenomenon persisted associated with acrocyanosis, white nails, and positive ANA (1:1280 in a nucleolar pattern). POEMS syndrome was suspected, and serum protein electrophoresis (SPEP) was done. The SPEP revealed polyclonal gammopathy, and serum immunofixation showed monoclonal (M)-protein (IgG lambda). Serum vascular endothelial growth factor concentration showed increased levels. The patient was diagnosed with POEMS syndrome, and treatment with lenalidomide and dexamethasone improved the Raynaud’s phenomenon, acrocyanosis, and white nails, but the neurological response was partial.

Conclusions

POEMS syndrome may mimic clinical manifestations of systemic sclerosis v.g. Raynaud’s phenomenon, skin thickening, telangiectasia, and positive ANA. Raynaud’s phenomenon may precede other clinical manifestations of POEMS syndrome by several months. It is necessary to have a high index of suspicion for the diagnosis, especially in patients with peripheral polyneuropathy and monoclonal paraprotein. The significance of positive ANA in this condition is unknown and deserves further investigation.