Intralymphatic histiocytosis was first described in 1994.1 To date, at least 70 cases have been reported in the English-language literature, the majority being associated with systemic or local inflammatory conditions such as rheumatoid arthritis (RA), malignancy, and metal prostheses. The remaining cases arose independent of any detectable disease process.2 The clinical lesion localizes to areas around surgical scars or inflamed joints and generally presents with erythematous livedoid papules and plaques. Because of its rarity, pathologists and clinicians may be unfamiliar with this entity, leading to delayed or missed diagnoses.
Although the pathogenesis of intralymphatic histiocytosis remains unclear, it may be related to dysregulated immune signaling. The condition follows a chronic, relapsing-remitting course that has shown variable response to topical and systemic treatments. We present a rare case of intralymphatic histiocytosis associated with joint replacement/metal prosthesis3-14 that was responsive to a novel treatment with intralesional steroid injection and pressure bandage.
Case Report
An 89-year-old woman presented with a relapsing and remitting rash on the right calf and popliteal fossa of 11 months’ duration. It was becoming more painful over time and recently began to hurt when walking. Her medical history was remarkable for deep vein thromboses of the bilateral legs, Factor V Leiden deficiency, osteoarthritis, and a popliteal (Baker) cyst on the right leg that ruptured 22 months prior to presentation. Her surgical history included bilateral knee replacements (10 years and 2 years prior to the current presentation for the right and left knees, respectively). Her international normalized ratio (2.0) was therapeutic on warfarin.
Initially, swelling, pain, and redness developed in the right calf, and recurrent right-leg deep venous thrombosis was ruled out by Doppler ultrasound. The findings were considered to be secondary to inflammation from a popliteal cyst. Symptoms persisted despite application of warm compresses, leg elevation, and compression stockings. Treatment with doxycycline prescribed by the patient’s primary care physician 9 months prior for presumed cellulitis produced little improvement. Physical examination revealed a well-healed vertical scar on the right calf from an incisional biopsy within an 8-cm, tender, erythematous, indurated, sclerotic plaque with erythematous streaks radiating from the center of the plaque (Figure 1). There also was red-brown, indurated discoloration on the right shin.
Figure 1. Well-healed vertical scar with 8-cm plaque of radiating erythema, induration, and sclerosis on the right calf, characteristic of intralymphatic histiocytosis.
Fine-needle aspiration of the lesion revealed red blood cells and histiocytes. Laboratory studies showed an elevated erythrocyte sedimentation rate of 74 mm/h (reference range, 0–30 mm/h) and a C-reactive protein level of 39 mg/L (reference range, 0–10 mg/L). An incisional biopsy including the muscular fascia showed dense dermal fibrosis with chronic inflammation and scarring. A dermatopathologist (G. A. S.) reviewed the case and confirmed variable fibrosis and chronic inflammation associated with edema in the dermis and epidermal acanthosis. Inspection of vessels in the mid to upper dermis in one area revealed stellate, thin-walled, vascular structures that contained bland epithelioid cells lining the lumen as well as packed within the vessels. The epithelioid cells did not show atypia or mitotic figures, and they did not show intracytoplasmic vacuoles (Figure 2). Immunocytochemical staining for D2-40 was strongly positive in cells lining the vessels, consistent with lymphatics (Figure 3). CD68 immunohistochemistry for histiocytes stained the cells within the lymphatics (Figure 4). A diagnosis of intralymphatic histiocytosis was made.
Figure 2. Excisional specimen from the right leg with thin-walled vessels packed with bland cells consistent with histiocytes (asterisks)(reference bar, ~40 μM)(H&E, original magnification ×200).
Figure 3. The cells lining the vascular spaces stained positively for D2-40, consistent with lymphatics (reference bar, ~40 μM)(original magnification ×200).
Figure 4. Histiocytes within the lumen of the lymphatics stained positively for CD68 (reference bar, ~40 μM)(original magnification ×200).
Intralesional triamcinolone acetonide 10 mg/cc×1.6 cc was injected into the plaque once monthly for 2 consecutive months, and daily compression with a pressure bandage of the right lower leg was initiated. Four months after the first treatment with this regimen, the plaque was smaller and no longer sclerotic or painful, and the erythema was markedly reduced (Figure 5). Clinical and symptomatic improvement continued at 1-year follow-up.
Figure 5. Site of the lesion 1 month after treatment with intralesional triamcinolone acetonide 10 mg/cc and daily pressure bandage wrapping for 2 months.