Pulmonary manifestations
Pulmonary cysts
Approximately 80-90% of patients with Birt-Hogg-Dubé syndrome have lung cysts.rr BHD-associated lung cysts likely develop in early to mid-adulthood. In sporadic primary pneumothorax, pulmonary cysts are typically found in the apical zones, while in BHD, the lung cysts are most often located in the basal regions.
Consequences of BHD-associated cystic lung disease appear worse in smokers.r
Avoid smoking.r
Pneumothoraces
The documented lifetime risk for incident pneumothorax ranges between 29%r and 76%.r Ascertainment bias is suspected to account for this variation with rates expected to be underestimated when recruitment was through a dermatology clinic and overestimated when recruitment was through a respiratory clinic. Risk factors for pneumothorax in this population include family history of pneumothorax, past history of pneumothorax, presence of lung cysts, cyst size and volume; while age and smoking status have not been consistently found to be associated with pneumothorax.rr
Facilitate patient education about the risk of future pneumothoraces. Refer to a respiratory physician prior to any high-risk activity e.g. scuba diving, high altitude mountain climbing.
Strongly recommend: medical alert bracelet, action plan for pneumothorax.
The reported recurrence rate of pneumothorax in BHD varies from 30% - 80%.rr The management of BHD-associated pneumothorax is similar to that for the general population.
Skin manifestations
Fibrofolliculomas, which are benign, are the most common skin manifestation occurring on the central face, neck and upper aspect of the trunk. They are present in the majority of BHD patients, and typically appear after age 20 years. If no lesions are present at age 40, they are unlikely to develop. Multiple biopsies and careful sectioning are often required for correct diagnosis. Other skin lesions associated with BHD include angiofibromas, trichodiscomas, perifollicular fibromas and epidermoid cysts.
Currently available treatments only remove cutaneous lesions temporarily; at the present time there does not appear to be a treatment that works permanently.
Renal cell carcinoma
Management depends on the lesion size, location, growth rate, number of tumours, and the patient’s comorbidities. In general, surgical resection with renal sparing surgery whenever possible is recommended once a solid lesion exceeds the 3 cm threshold.r
Ablation methods, such as radiofrequency ablation (RFA) or cryoablation therapy, are not recommended in patients who are good surgical candidates as previous ablation may complicate subsequent surgical procedures and can also make post-ablation imaging difficult to interpret.r