Multicentric Reticulohistiocytosis Progressing to Erythroderma After Long-Term Disease Progression

Area of Science:

• Rheumatology
• Dermatology
• Rare Diseases

Background:

• Multicentric reticulohistiocytosis (MRH) is a rare non-Langerhans cell histiocytosis.
• MRH is characterized by destructive polyarthritis and papulonodular cutaneous lesions.
• The disease typically requires long-term management with various therapeutic agents.

Purpose of the Study:

• To report a previously undocumented manifestation of MRH.
• To describe the clinical course and management of a patient with MRH who developed erythroderma.
• To investigate the potential link between long-standing MRH and erythrodermic presentation.

Main Methods:

• Case report of a 71-year-old woman with a 20-year history of MRH.
• Clinical evaluation including skin biopsies, laboratory tests, and imaging studies.
• Review of treatment history including methotrexate, prednisolone, infliximab, and bone-modifying agents.

Main Results:

• The patient developed erythroderma 20 years after MRH diagnosis, a novel presentation.
• Skin biopsies confirmed histiocytic infiltrate identical to original MRH lesions.
• Exclusion of other causes of erythroderma, including infections, malignancies, and other inflammatory conditions.
• Erythroderma resolved with increased prednisolone dosage after methotrexate discontinuation due to interstitial pneumonia.

Conclusions:

• Erythroderma can be a rare, late-onset manifestation of Multicentric Reticulohistiocytosis.
• The cumulative inflammatory burden of MRH may contribute to the development of erythroderma.
• This case expands the known clinical spectrum of MRH and emphasizes the need for comprehensive evaluation in patients with long-standing disease.