Birt-hogg-Dubé Syndrome Incidentally Identified in a Potential Liver Donor

Background: Birt-Hogg-Dubé Syndrome (BHDS), an autosomal dominant hereditary condition, occurs due to mutations in the gene encoding folliculin (FLCN) in the short arm of the 17th chromosome characterized by lung cysts with specific skin findings and renal cell carcinoma. Patients have usually complaints related to dyspnea and chest pain due to pneumothorax but they may be asymptomatic due to wide phenotypic heterogeneity. Herein, we report the imaging findings of a case 32-year-old male with BHDS without any symptom who was diagnosed incidentally by computed tomography (CT) due to organ donation. Case Report: In a 32-year-old male patient evaluated as a potential liver donor, CT was performed for preoperative preparation. The patient's medical history was unremarkable. In the CT examination, multiple air cysts of different sizes in both lungs were observed and also, a 7-cm solid renal mass of the right kidney was observed in the dynamic examination. Due to a large number of lung cysts and the presence of solid renal tumors at a young age, BHDS was considered. The patient underwent partial nephrectomy, and the pathology result was hybrid oncocytic-chromophobe renal cell carcinoma. In the genetic examination, a heterozygous germline mutation was detected in the 11th exon of the FLCN gene. Conclusion: While potential organ donors are generally healthy and asymptomatic individuals, incidental lesions can be detected in the donor organ or other organs in the examination area during radiological imaging. Although most incidental lesions are benign, important clinical conditions can rarely be observed, as in our case. Familial and syndromic conditions should also be considered for the presence of solid renal masses incidentally detected at a young age. To the best of our knowledge, this is the first reported case of BHDS in English literature who was diagnosed incidentally on computed tomography for being a living liver donor.