Multicentric Reticulohistiocytosis — SCE Rheumatology MCQ

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HardConnective Tissue DiseaseMulticentric ReticulohistiocytosisSCE Rheumatology

A 65-year-old man presents with progressive finger swelling and a rapidly destructive arthropathy affecting the distal and proximal interphalangeal joints. He has multiple skin-coloured to reddish-brown papules and nodules over his hands and face. Biopsy of a nodule shows an infiltrate of histiocytes and multinucleated giant cells with abundant eosinophilic ground-glass cytoplasm. What is the most likely diagnosis?

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Correct answer: C — Multicentric reticulohistiocytosis

The diagnosis is **multicentric reticulohistiocytosis**, a rare non-Langerhans-cell histiocytosis characterised by papulonodular skin lesions and an aggressive erosive arthropathy, often involving the interphalangeal joints and sometimes progressing to arthritis mutilans. The decisive finding is the infiltrate of histiocytes and multinucleated giant cells with eosinophilic ground-glass cytoplasm. Psoriatic arthritis can destroy DIP joints but does not produce this histology. Gouty tophi contain urate crystal deposits with a foreign-body reaction. Rheumatoid nodules show palisading histiocytes around fibrinoid necrosis, while xanthomas predominantly contain foamy histiocytes and may contain Touton giant cells. Multicentric reticulohistiocytosis has a recognised association with malignancy, so age-appropriate assessment for an underlying neoplasm is warranted.

Reference: Clinical Case Reports. Multicentric Reticulohistiocytosis—A rare and disabling disease. 2023. https://pubmed.ncbi.nlm.nih.gov/37645054/