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.
A 37-year-old man presented with an asymptomatic right renal mass detected by ultrasonography and CT (Fig. a). No apparent cutaneous lesions were found by careful inspection and palpation of the skin. The patient had a history of spontaneous pneumothorax on both sides and underwent pulmonary bullectomy on the right side at the age of 30. His father had a history of recurrent spontaneous pneumothorax starting at the age of 28 and died of stoke at the age of 63. His uncle had a history of recurrent spontaneous pneumothorax starting at the age of 24 and died of an accident at the age of 56. Open partial nephrectomy was performed on the patient. Histopathologic examination revealed that the tumor was chromophobe RCC, nuclear grade G2, and 2.2 cm × 2.0 cm × 2.0 cm in size (Fig. b).\nGenomic DNA was extracted from blood samples collected from the patient and his family members. Mutation examination revealed that the proband carried a deletion of three bases (CCT) at nucleotides c.770-772 in exon 7 (c.770-772delCCT) (Fig. c), resulting in deletion of the 257th serine residue (p.257delS). No FLCN mutations were found in any other members of the patient’s family.