A Case of Gonadotropin-Releasing Hormone Agonist-Induced Sterile Abscess Showing a Good Response to Systemic Steroid Therapy.

Abstract

Dear Editor: Prostate cancer is a common malignancy in men, and its incidence is increasing rapidly. Because prostate cancer shows androgen dependency in the early stages1, androgen-deprivation therapy with gonadotropin-releasing hormone (GnRH) agonists is the most effective systemic treatment2. Leuproreline (Lucrin; Abbot, Amstelveen, The Netherlands) is a GnRH agonist that blocks pituitary GnRH receptors, leading to the downregulation of luteinizing hormone and follicle-stimulating hormone3. This chemical castration provides long-term maximal androgen deprivation1. A 79-male-old man, who had painful tender erythematous subcutaneous nodules on the abdomen, visited our dermatologic department in June 2012. He received androgen-deprivation therapy consisting of pretreatment with leuprorelin 11.25 mg at 3-month intervals to treat underlying prostate cancer. A lesion arose from a previous leuprorelin injection site 2 weeks after the last injection (Fig. 1A). He was initially treated with antibiotics and non-steroidal anti-inflammatory drugs, but no improvement was observed. Subsequent histological examination showed neutrophilic and eosinophilic infiltration in the reticular dermis (Fig. 2). Laboratory examination results, including bacterial culture and tuberculosis polymerase chain reaction, were negative. Therefore, he was diagnosed with a sterile abscess caused by GnRH agonist injection and treated with systemic methylprednisolone 16 mg/day. The lesion had almost cleared after 4 weeks and remains in remission as of writing (Fig. 1B). Fig. 1 Painful tender erythematous subcutaneous swelling on abdomen. (A) Before treatment. (B) After 4 weeks of systemic steroid therapy. Fig. 2 Histologic slide stained with hematoxylin and eosin reveals neutrophilic and eosinophilic infiltrates in the reticular dermis. Leuprorelin, a GnRH agonist, is the most effective therapeutic modality for prostate cancer. Although GnRH agonist therapy appears to have significant benefits for patients, it also has serious side effects including anemia, cognitive changes, obesity, lipid alterations, insulin resistance, coronary artery disease, and osteoporosis2,3. The efficacy and side effects of GnRH agonists have recently been reported. In particular, sterile abscess formation has been reported in 3% of patients who received a GnRH agonist4. In Korea, only two patients, who were injected with a GnRH agonist for the treatment of central precocious puberty, have been reported to have developed a sterile abscess at the injection site5. Thus, our case is the first case of a sterile abscess in a Korean patient with prostate cancer treated with leuprorelin. There are many theories about the cause of sterile abscess5. One possible cause is an additive polymer of leuprorelin similar to that used in resorbable sutures. However, there is a report about granulomatous reactions induced by leuprorelin alone3. Thus, this could be thought of as a positive allergic reaction to leuprorelin. Furthermore, these reactions occurred in patients who received daily subcutaneous leuprorelin injections without additive polymer5. Thus, these cases suggest leuprorelin itself could be the cause of sterile abscess and granulomatous reaction. Previous reports describe spontaneous healing of sterile abscesses over several months without treatment4,5. Our patient was treated with a systemic steroid and remained in remission for 1 month. Thus, systemic steroid therapy may be a potential therapeutic modality for GnRH agonist-induced sterile abscess. Dermatologic clinicians should be aware of the potential adverse effects of leuprorelin injection, including sterile abscess and granulomatous reactions.