Paecilomyces lilacinus infections are quite rare. Most reports involve immunocompromised patients or implanted objects. We report the first case of complicated soft tissue infection caused by P. lilacinus in an immunocompetent host. The spectrum of infections involving this fungus is reviewed. Paecilomyces species are widely distributed throughout the environment. They are frequently detected in soil samples (3, 5, 9, 16), decomposing vegetation (29), and as airborne contaminants (22). Despite its ubiquity, Paecilomyces lilacinus remains an uncommon cause of fungal infections in humans. The majority of case reports describe ocular infections (1, 6, 10, 13, 14, 16, 18, 19, 27). Others have implicated Paecilomyces lilacinus as a cause of dermatologic infection (2, 8, 15, 28), sinusitis (23, 24), pulmonary mycosis (4), an abdominal wall abscess (26), and fungemia related to an indwelling catheter (29). We describe the first reported case of deep soft tissue infection with bursitis caused by Paecilomyces lilacinus in an immunocompetent host. Surgery and prolonged antifungal therapy were required to eradicate the infection. Case report. A 35-year-old male Caucasian presented to a general internist complaining of pain and swelling below his right knee for 5 days. The patient was employed as an auto mechanic and stated that his pain began after working on his knees on a cement floor. He did not recall any break in the skin or any injury involving a foreign body. A diagnosis of pretibial effusion was made, and fluid was aspirated. A swab culture of the fluid for aerobic bacteria revealed no growth. The patient saw a second physician shortly thereafter, with the same complaints. The area was again aspirated and then injected with a corticosteroid. Cultures were not obtained. Although his symptoms improved briefly, pain and swelling returned 2 months later, at which time the patient was evaluated by an orthopedic surgeon. A radiograph of the knee was normal, and a clinical diagnosis of prepatellar bursitis was made. One week later, he was examined by a rheumatologist, who aspirated a fluctuant pretibial lesion. Four milliliters of purulent material contained 183,000 polymorphonuclear leukocytes per mm 3 , 30,000 erythrocytes per mm3, and a glucose level of 4 mg/dl. Gram's stain revealed many polymorphonuclear leukocytes but no organisms. Treatment with oral cefaclor was initiated. Cultures for aerobic bacteria and mycobacteria were subsequently negative, but a mould was isolated from the aspirated pus. The patient's signs and symptoms did not improve with the antibiotic, and he developed a temperature of 101 to 102ЊF (ϳ38.5 to 38.7ЊC). Five days later his