The second patient was a 35-year-old male who presented with an asymptomatic right renal tumor. The presence of the tumor was revealed by ultrasound and CT examinations (fig. ). A laparoscopic right partial nephrectomy was performed, and the tumor was diagnosed as a chromophobe renal cell carcinoma (RC; fig. ). The carcinoma was negative for CD10, vimentin, and c-kit, and was partially positive for CK-7 (fig. ) and colloidal iron (fig. ). When the patient was 40 years of age, a CT examination revealed the presence of asymptomatic bilateral multiple PCs (fig. ). His mother, aunt, uncle, and grandfather all had histories of recurrent pneumothorax (fig. ). A few firm papules were also present on the patient's face (fig. ). The results of the skin biopsies revealed that the papules were FFs (fig. ) positive for factor 13a (fig. ) and c-kit (fig. ), and negative for CD34, α-SMA, S100, and CD68. Because the findings for this patient met 1 major criterion and 2 minor criteria [], he was diagnosed with BHD.
The first patient was a 37-year-old female who presented with an asymptomatic left renal tumor that was revealed by ultrasound and computed tomography (CT) examinations (fig. ). The CT examination also revealed the presence of asymptomatic bilateral multiple PCs (fig. ). Since the age of 35, a few firm papules had developed on her face and head (fig. ). The patient had no family history of pulmonary, renal, or cutaneous disease. A laparoscopic left nephrectomy was performed. On gross examination, the resected kidney was a yellowish, solid tumor with partial hemorrhage (fig. ). The tumor was identified as a clear cell renal carcinoma (fig. ) positive for vimentin stain (fig. ) and negative for CK-7. A skin biopsy of the papule on her head revealed it was a fibrofolliculoma (FF; fig. ) positive for factor 13a (fig. ) and c-kit (fig. ), and negative for CD34, α-smooth muscle actin (α-SMA), S100, and CD68. Because the findings for this patient met 1 major criterion and 2 minor criteria [], she was diagnosed with Birt-Hogg-Dubé syndrome (BHD).