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).