25: Clinical manifestations of Birt-Hogg-Dube Syndrome in a large clinical cohort

Location: Poster Hall, Board C1

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Table 1

Renal mass, pulmonary, and dermatologic characteristics with associated mutation status

Poster Presenter(s)

RC

Raju Chelluri, MD, M.S

Fellow in Urologic Oncology
Fox Chase Cancer Center, United States

Background: Birt-Hogg-Dube (BHD) syndrome is an underdiagnosed autosomal dominant condition caused by folliculin (FLCN) gene mutations and is characterized by fibrofolliculomas, pulmonary cysts, and renal masses. Our study characterizes our center’s cohort of BHD patients to describe the range of presentations.

Methods: A single center, retrospective cohort study of patients with BHD syndrome was performed. The medical record was queried for clinical data corresponding to renal mass, pulmonary, and dermatologic findings. Results were reported as median and inter-quartile range (IQR). Germline mutation status is reported.

Results: Eighty-one BHD patients were identified. Median age of BHD diagnosis was 38 (28-57) years old. Ten (12.3%) patients had a total of 15 renal masses. Age at first tumor diagnosis was 58 [50.8-60.2] years with median lesion size being 1.5 [1-2.1] cm. Six (60%]) tumor patients were managed non-operatively and 4 (40%) underwent resection. Surveilled tumor growth rate was 0 [-0.02 – 0] cm/yr during a median 2.3 [2.3-5.6] year follow-up. Twenty-six (32.1%) patients had characteristic skin findings at diagnosis with fibrofolliculomas being documented in 47 (58%) total patients at a median age of 46.5 (33-58) years. Twenty-eight (34.6%) patients had a history of pneumothorax at diagnosis with pneumothorax affecting 34 (42%) total patients. Notably, 9/47 (19.1%) patients with fibrofolliculomas and 4/34 (11.8%) patients with pneumothorax history had a renal mass. Four (40%) renal tumor patients had pneumothorax history.

Conclusions: Renal tumors were found to affect 12.3% of BHD patients in this clinical cohort. BHD-associated renal masses were noted to mostly small, indolent with a static growth rate. Only 19% patients with fibrofolliculomas and 12% of patients with pneumothorax developed a renal mass. Of patients with a renal mass, 40% experienced a pneumothorax in their lifetime. Limitations of this study include its retrospective nature, small sample size of BHD patients with renal lesions, and low follow-up time.