Case Report Synchronous chromophobe and papillary renal cell carcinoma. First report and review of the pathogenesis theories Stavros Ioannis Tyritzis, 1 Paraskevi Theodoros Alexandrou, 2 Vasileios Migdalis, 1 George Koritsiadis 1 and Ioannis Anastasiou 1 1 Department of Urology, Athens University Medical School, LAIKO Hospital, and 2 Department of Pathology, Athens University Medical School, Athens, Greece The coexistence of different subtypes of renal cell carci- noma (RCC) within a single kidney is an extremely unusual entity. Presented herein is the case of a 57-year-old man with two RCC of chromophobe and papillary histology. Very few reports in the literature describe double or triple synchronous renal neoplasms. To our knowledge this is the first report of this RCC subtype combination, which might trigger further investigation on the RCC pathogen- esis theories. Key words: chromophobe, papillary, pathogenesis, renal cell carcinoma The presence of concurrent subtypes of renal cell carcinoma (RCC) is a very uncommon entity, because the majority of cases include one histological type, which might show spatial variability in specific growth patterns. The presented case illustrates the first combination of two dissimilar RCC sub- types, one in the upper and the second in the lower pole of the same kidney. In addition, we review probable theories of the pathogenesis of such rare conditions. CLINICAL SUMMARY A 57-year-old man was admitted to Department of Urology, Athens University Medical School–LAIKO Hospital for sched- uled right radical nephrectomy after being incidentally diag- nosed with a large neoplasm of the lower pole of the right kidney. The diagnosis was made on routine ultrasound, fol- lowed by CT of the abdomen (Fig. 1). The patient’s medical history consisted of a painless microscopic hematuria 15 years previously confirmed on i.v. urography with no find- ings, and arterial hypertension controlled by medication. A left saphenous vein thrombosis was described 2 months before admission. Physical examination and laboratory data were normal. The patient underwent a right radical nephrectomy, and the postoperative course was uneventful. PATHOLOGICAL FINDINGS On gross examination the kidney contained a large, light brown and yellowish solid tumor occupying the lower pole, measuring approximately 12.5 ¥ 10.5 ¥ 4.5 cm (tumor 1). At 7 cm away from the aforementioned lesion, a second, yel- lowish mass located in the upper pole and measuring 5 ¥ 4.7 ¥ 4 cm was also observed (tumor 2). Tumor 2 was well circumscribed and exhibited areas of hemorrhage and necro- sis (Fig. 2). Fresh tissue was fixed in buffered formalin. Paraffin- embedded sections were stained with standard HE. Tumor 1 Microscopy indicated a pT2 chromophobe renal cell carcinoma according to the TNM classification, with solid growth pattern and often a clear perinuclear region (Fig. 3a). Tumor cells were large, round to polygonal with well-defined cell borders and abundant translucent cyto- plasm. These cells seemed to admix with a smaller popu- lation of cells with eosinophilic ‘oncocytic’ cytoplasm. The nuclei were hyperchromatic with focally wrinkled contour and some of them were bizarre. Binuclear and multinucle- ated tumor cells were also present. Tumor 1 was finally graded as 3 according to the Furhman grading system. Immunohistochemically, the tumor was positive for epithelial Correspondence: Stavros Tyritzis, MD, Department of Urology, Athens University Medical School, LAIKO Hospital, 17 Agiou Thoma str., 11527, Athens, Greece. Email: statyr@freemail.gr Received 15 July 2008. Accepted for publication 26 October 2008. © 2009 The Authors Journal compilation © 2009 Japanese Society of Pathology Pathology International 2009; 59: 193–196 doi:10.1111/j.1440-1827.2009.02350.x