Intralymphatic Histiocytosis Associated With Orthopedic Implants

Intralymphatic histiocytosis (IH) is a rare condition characterized by asymptomatic, papules, vesicles, or nodules in a livedo reticularis-like pattern.¹ First described by O'Grady et al., this is a rare condition with an unknown exact incidence.^2,3 Although the majority of cases occur in association with rheumatoid arthritis (RA), recent literature reveals patients developing IH after joint replacementsin the absence of RA.

We describe a 78-year-old male who presented with a 1.5 cm erythematous nodule, surrounded by a peripheral 15 cm area of reticulate erythema on the right thigh of 1.5 months duration (Figure 1). There was no associated lymphadenopathy.

The lesion was initially mildly pruritic, but asymptomatic at presentation. There was no history of trauma and the lesion did not improve despite treatment with clobetasol cream for one month. The history was significant for a right hip replacement (15 years prior) and bilateral knee replacements (3, 6 years prior), due to mechanical injury. The review of symptoms was negative for fever or joint pains.

Two biopsies were performed, one of the erythematous nodule and the other of the reticulate erythema. Histology of both tissue samples showed an unusual proliferation of irregular vascular structures lined by atypical endothelial cells with a mixed in- flammatory cell infiltrate (Figure 2a-b). Immunohistochemistry demonstrated CD-68 and HAM56 positive macrophages in dilated CD31 and D2-40 positive lymphatic channels, confirming a diagnosis of IH (Figure 3a-d).

IH is a rare condition, mostly reported in adults or elderly patients. ³ Patients present with asymptomatic, poorly demarcated and irregularly shaped erythematous patches or plaques often in a livedo reticularis-like pattern. Lesions may be papular, vesicular, or nodular and have a predilection for the extremities. The condition has been reported in association with rheumatoid arthritis and joint replacements (Table 1).