WORLD JOURNAL OF SURGICAL ONCOLOGY Michalaki et al. World Journal of Surgical Oncology 2010, 8:45 http://www.wjso.com/content/8/1/45 Open Access CASE REPORT © 2010 Michalaki et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Case report Abscess formation mimicking disease progression, in a patient with metastatic renal cell carcinoma during sunitinib treatment Vasiliki Michalaki* 1 , Nikolaos Arkadopoulos 2 , Agathi Kondi-Pafiti 3 and Constantine Gennatas 1 Abstract Background: Renal cell carcinoma (RCC) represents approximately 3% of all adult cancers and is more common in males. Systemic treatment for RCC has improved following the introduction of tyrosine kinase inhibitors, such as sunitinib. The molecular targets of sunitinib are receptor tyrosine kinases (RTKs). Moreover, sunitinib has an additional anti-angiogenic effect through its inhibition of the vascular endothelial growth factor receptor activation. Case presentation: We present a case of intra-abdominal abscess formation mimicking disease progression, in a patient with metastatic renal cell carcinoma during sunitinib treatment. Conclusion: In the advancing era of molecular therapy of solid tumours, sunitinib has demonstrated significant efficacy in the post-cytokine setting treatment of metastatic renal cancer. Concurrently, however, increasing evidence has emerged to indicate that this class of drugs exert profound immunomodulatory effects on T cells and play major roles in immune tumor surveillance. Background The treatment of advanced RCC is undergoing a para- digm shift with the recent introduction of anti-angio- genic therapy that either directly inhibits vascular endothelial growth factor or disrupts signal transduction favorable to vascular development through multi-kinase inhibitors. Angiogenic inhibitors have been found to increase survival and are approved in advanced renal cell carcinoma [1,2]. Consequently, most of these patients will routinely receive tyrosine kinase inhibitors, such as suni- tinib. Sunitinib is an orally administered, small molecule inhibitor of multiple receptor tyrosine kinases implicated in tumour growth, angiogenesis, and metastatic progres- sion. In addition, the targets of sunitinib involve vascular endothelial growth factor receptors (VEGFR1, VEGFR2 and VEGFR3), platelet-derived growth factor receptors (PDGFRα and PDGFRβ) and the like. We describe a case of intra-abdominal abscess formation mimicking disease progression during sunitinib treatment. Case presentation A 62-year-old patient diagnosed with a high-grade clear- cell renal carcinoma in 1991 and was treated by left neph- rectomy and surrenalectomy. Fourteen years later, relapsed on the lungs and had been administered inter- feron alfa. The patient was regularly followed up and had regular scans that did show stabilization of the disease in the lungs for two years. In December 2007 chest comput- erized tomography (CT) disclosed the progression of lung metastases. Sunitinib was initiated in January 2008 as a standard regimen (50 mg/day for 4 weeks every 6 weeks) for pulmonary metastases. Patient had a radio- graphic response and prolonged progression free survival of fourteen months; side effects were manageable and included grade 2 hypertension. After five cycles, the patient was admitted to the hospital due to complaints of fatigue and left sided flank pain. The systolic and diastolic blood pressures were 110 mmHg and 60 mmHg, respec- tively, pulse rate was 90 per min and respiratory rate was 20 per min. The body temperature was 37.2°C. Laboratory studies were conducted immediately after the patient's arrival at the hospital. He had anemia (Hb 98 g/L) (normal range: 140-180) and thrombocytopenia (133 × 10 9 /L) (normal range: 150-450), but a WBC count was * Correspondence: vmichalaki@usa.net 1 Oncology Clinic, Second Department of Surgery, University of Athens, Aretaieion Hospital, 78, V. Sofias av, 115 28, Athens, Greece Full list of author information is available at the end of the article