A 54-year-old man was found to have asymptomatic, bilateral renal tumors by ultrasonography and computed tomography (CT) (Fig. a, b). CT scan also showed left pneumothorax (Fig. c). No apparent cutaneous lesions were found by careful inspection and palpation of the skin. The patient had a history of spontaneous pneumothorax at the age of 30. His son also had a history of spontaneous pneumothorax at the age of 17. Open bilateral and partial nephrectomies were performed. Histopathologic examination revealed that the tumor in the left kidney was chromophobe RCC, nuclear grade G2 (partial G1), and 1.7 cm × 1.5 cm × 1.5 cm in size (Fig. d); the tumor in the right kidney was clear-cell RCC, nuclear grade G2, and 5.0 cm × 4.7 cm × 4.5 cm in size (Fig. e).\nGenomic DNA was extracted from blood samples collected from the patient and his son. Mutation examination revealed that the proband and his son carried a deletion of two bases (AG) at nucleotides c.946-947 in exon 9 (c.946-947delAG) of the FLCN gene (Fig. f), which caused a frameshift mutation starting at the 316th amino acid (p.316fs388x). No RCC was detected by abdominal CT scan on the son.
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.