A 56-year-old female presented with a 6-month history
of asymptomatic red plaques on her hands. She had
an underlying history of arthritis in her hands and feet.
She was initially treated for granuloma annulare with topical
steroids, but no improvement was noted.
Examination of the bilateral dorsal hands showed multiple violaceous
plaques, some with an annular appearance (Figures 1
and 2). No nail involvement was noted.
Complete blood cell count, rheumatoid factor assay, and serum
protein electrophoresis were within normal limits. Lipid concentration
panel showed hypercholesterolemia. Radiographs
of the bilateral hands revealed narrowing of the proximal and
distal interphalangeal joint spaces.
Biopsy showed a dermal lymphohistiocytic infiltrate with
prominent multinucleated giant cells containing abundant eosinophilic
cytoplasm (Figure 3).
Multicentric reticulohistiocytosis (MRH) is a rare histiocytic
proliferative disease with unknown etiology. MRH features
widespread cutaneous disease along with a destructive arthritis,
typically presenting in females in the fifth or sixth decade
of life. A classic nail finding is the "coral bead sign," where
multiple small papules trail along the nail fold.
The polyarthritis is diffuse, symmetric, progressive, and destructive
of the articular cartilage and subarticular bone. There
is a predilection for the distal interphalangeal joints. The associated
arthritis is caused by the same type of infiltrate as is
found in the cutaneous lesions.
Additional systemic associations include hyperlipidemia
(30%-50%), internal malignancy (15%-30%),1 and autoimmune
disease (5%-15%). MRH precedes the diagnosis of
malignancy in 75% of cases.2
Histopathologically, MRH is similar to giant cell reticulohistiocytoma.3 Both have numerous multinucleate giant cells and
oncocytic macrophages showing abundant eosinophilic fine,
grainy cytoplasm, which has the characteristic "ground glass"