Invasive aspergillosis can be occured in immune-compromised patients with hematopoietic stem cell transplantation, solid organ transplantation and prolonged neutropenia. The major area of invasive aspergillosis involves the sinopulmonary tract but can occur around the joint areas rarely. A 72-year-old man, who had received a liver transplant 6 years earlier, presented with a mass lesion around the right knee joint that developed 3 year earlier. Knee MRI revealed a multicystic subcutaneous mass around the knee joint. An excision was performed, and many fungal hyphae that were morphologically most consistent with Aspergillus spp. were observed in tissue. After amphotericin B therapy for 2 weeks, the patient did not show any evidence of a recurrence of invasive aspergillosis for 15 months. As Aspergillus spp. can cause a range of infections in solid organ transplants, invasive aspergillosis must be considered in patients with a recurrent cystic mass lesion.