Intralymphatic histiocytosis is a rare disorder associated with a variety of inflammatory conditions. We report the case of an 89-year-old woman with a history of a right knee replacement and a ruptured popliteal cyst who developed an erythematous indurated plaque over the surgical scar. Histopathology revealed fibrosis, chronic inflammation, and histiocytes within the lymphatics consistent with intralymphatic histiocytosis. The plaque flattened following intralesional injection of triamcinolone acetonide 10 mg/cc×1.6 cc once monthly for 2 consecutive months and application of a pressure bandage, with no recurrence after 4 months. This treatment may be useful for recalcitrant disease.