A 54-year old man with asymptomtic, tiny, multiple, flesh-colored papules on both cheeks () was referred to us from the cardiothoracic surgery department, where he had been treated for recurrent pneumothorax of the left lung. He did not remember the onset of the lesions, but stated that the number was increasing. He had no special medical or family history. The papules were thought to be sebaceous hyperplasia or verruca plana and a punch biopsy was performed. The specimen showed an epithelial cord and fibrous stroma in the dermis and an anastomosing band from follicular epithelium (). A diagnosis of fibrofolliculoma was made, which is the major feature of BHDS.\nThere was no family history of the skin lesions, lung disease, and of benign or malignant tumors. Furthermore, multiple variable-sized lung cysts were found on his chest following computed tomographic scan and a right renal cyst 2 cm in diameter was found on abdominal sonography (). Molecular analysis of FLCN was performed after informed consent from the patient. Sequencing revealed a single nucleotide frameshift duplication occurring within the polycytosine tract located in exon 11, c.1285dupC (p.H429Pfs*27), resulting in a change of the 429th amino acid from histidine to proline in the FLCN gene product. Based on this, it is possible to accurately diagnose BHDS.\nHis pneumothorax was treated with thoracostomy and pleurodesis, and active treatment was not required for the skin lesions, lung cysts and renal cyst. He is on regular follow-up because renal and colorectal cancer can occur in this syndrome.
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.