Case Report: Expanding the tumour spectrum associated with the Birt-Hogg-Dubé cancer susceptibility syndrome

ERN GENTURIS clinical practice guidelines for the diagnosis, surveillance and management of people with Birt-Hogg-Dubé syndrome

Birt-Hogg-Dubé syndrome (BHD syndrome) is an autosomal dominant multisystem disorder with variable expression due to pathogenic constitutional variants in the FLCN gene. Patients with BHD syndrome are predisposed to benign cutaneous fibrofolliculomas/trichodischomas, pulmonary cysts with an associated risk of spontaneous pneumothorax, and renal cell carcinoma. A requirement for updated International consensus recommendations for the diagnosis and management of BHD syndrome was identified. Based on a comprehensive literature review and expert consensus within the fields of respiratory medicine, urology, radiology, dermatology, clinical oncology and clinical genetics, updated recommendations for diagnosis, surveillance and management in BHD syndrome were developed. With the widespread availability of FLCN genetic testing, clinical scenarios in which a diagnosis should be considered and criteria for genetic testing were defined. Following a clinical and/or molecular diagnosis of BHD syndrome, a multidisciplinary approach to disease management is required. Regular renal cancer surveillance is recommended in adulthood and life-long, but the evidence base for additional tumour surveillance is limited and further research warranted. Recommendations for the treatment of cutaneous, pulmonary and renal manifestations are provided. Awareness of BHD syndrome needs to be raised and better knowledge of the clinical settings in which the diagnosis should be considered should enable earlier diagnosis. Further details, including areas for future research topics are available at: https://www.genturis.eu/l=eng/Guidelines-and-pathways/Clinical-practice-guidelines.html .

Concurrent Birt-Hogg-Dubé Syndrome and Hereditary Paraganglioma-Pheochromocytoma Syndrome Presenting as Metastatic Renal Cell Carcinoma in a 25-Year-Old Man: A Case Report

INTRODUCTION

Birt-Hogg-Dubé syndrome and hereditary paraganglioma-pheochromocytoma syndrome are rare genetic cancer syndromes that predispose patients to renal neoplasia. We report a case of a 25-year-old man with both Birt-Hogg-Dubé syndrome and hereditary paraganglioma-pheochromocytoma syndrome who presented with painless gross hematuria and was found to have metastatic clear cell renal carcinoma.

CASE PRESENTATION

A previously healthy, 25-year-old man presented to his outpatient primary care physician with painless gross hematuria. Urinalysis results demonstrated hemoglobinuria, and serum chemistry results demonstrated a creatinine level of 1.61 mg/dL (baseline of 0.96 mg/dL). A computed tomography scan showed that the patient had a left renal mass, renal vein thrombosis with inferior vena cava extension, and nodal and hepatic metastasis. Biopsy specimens of the left renal mass and liver demonstrated clear cell carcinoma. The patient underwent cytoreductive nephrectomy, caval thrombectomy, and partial colectomy with reanastomosis. He received palliative therapy with 1 mg/kg of ipilimumab and 3 mg/kg of nivolumab for 4 cycles.

CONCLUSION

To our knowledge, this is the first known case report to date documenting a patient with concurrent Birt-Hogg-Dubé syndrome and hereditary paraganglioma-pheochromocytoma syndrome. This case demonstrates the exceptionally young presentation of metastatic renal cell carcinoma with this genotype.

Update on Hereditary Renal Cancer and Imaging Implications

Up to 8% of renal cancers are thought to have a hereditary component. Several hereditary renal cancer syndromes have been identified over the last few decades. It is important for the radiologist to be aware of findings associated with hereditary renal cancer syndromes to detect tumors early, enroll patients in appropriate surveillance programs, and improve outcomes for the patient and affected family members. This review discusses from a radiologist's perspective well-known hereditary renal cancer syndromes and emerging genetic mutations associated with renal cancer that are less well characterized, focusing on imaging features and known associations.

Adult rhabdomyoma presenting as thyroid nodule on fine-needle aspiration in patient with Birt-Hogg-Dubé syndrome: Case report and literature review

Extracardiac rhabdomyoma is an uncommon benign striated muscle tumor with a predilection for the head and neck region. However, it is extremely rare for extracardiac rhabdomyoma to present as a thyroid nodule. We report a case of rhabdomyoma diagnosed by thyroid fine-needle aspiration (FNA) in a patient with Birt-Hogg-Dubé (BHD) syndrome. A 60-year-old man with BHD syndrome presented for recurrent pneumothorax. Chest CT incidentally identified a thyroid nodule. Subsequent sonography confirmed a 4.44 × 2.28 × 2.82 cm solid, hypoechoic nodule with smooth margins in the right upper pole. Ultrasound-guided FNA revealed many clusters and scattered isolated large polygonal cells with abundant granular cytoplasm and small peripherally located nuclei. Vague striations in the cytoplasm were focally identified. No follicular cells or colloid was present. Immunocytochemistry on one direct smear slide demonstrated diffuse positivity for desmin, supporting muscular differentiation. Subsequent surgery identified an adult rhabdomyoma originating from the inferior constrictor muscle of the neck and anteriorly displacing the thyroid. Because the mass was intimately associated with the thyroid gland, it was initially mistaken for a thyroid nodule on ultrasound. Diagnosis of rhabdomyoma on FNA is challenging, especially when rhabdomyoma mimics a thyroid nodule on imaging. The differential diagnosis includes Hurthle cell neoplasm, granular cell tumor, colloid nodule, and normal striated skeletal muscle. Adequate radiologic data and familiarity with the cytologic features of rhabdomyoma are critical for an accurate diagnosis.

Birt-Hogg-Dubé Syndrome: A Review of Dermatological Manifestations and Other Symptoms

Birt-Hogg-Dubé syndrome (BHD) is an autosomal dominant genodermatosis with malignant potential characterized by cutaneous and extracutaneous stigmata. Aberrations in the folliculin (FLCN) gene, which is located on chromosome 17, have been discovered in individuals with this condition. Over 150 unique mutations have been identified in BHD. The skin lesions associated with this condition include fibrofolliculomas, trichodiscomas, perifollicular fibromas, and acrochordons. Extracutaneous features of the syndrome typically include the lung (spontaneous pneumothorax and cysts) and the kidney (neoplasms). The only malignancies associated with BHD are renal cancers; however, other tumors have been observed in individuals with BHD. In this article, the skin lesions associated with this condition are reviewed, lung and renal manifestations associated with this syndrome are presented, and malignancies occurring in these patients are summarized.

Genetic, epidemiologic and clinicopathologic studies of Japanese Asian patients with Birt-Hogg-Dubé syndrome

Birt-Hogg-Dubé syndrome (BHD) is a rare genetic disorder characterized by fibrofolliculomas, pulmonary cysts and renal cell carcinomas (RCCs). The affected individuals inherit germline mutations in the folliculin gene (FLCN). We investigated the mutation spectrum and clinicopathologic findings of 312 patients from 120 different families (119 Japanese and 1 Taiwanese). A total of 31 different FLCN sequence variants were identified. The majority were c.1285dupC (n = 34), c.1533_1536delGATG (n = 25), and c.1347_1353dupCCACCCT (n = 19). Almost all patients presented with pulmonary cysts. The incidence of RCCs in FLCN mutation carriers over the age of 40 was 34.8% (40/115). Fifty-five RCC lesions were surgically resected; most were either chromophobe RCC (n = 24; 43.6%) or hybrid oncocytic/chromophobe tumors (19; 34.5%). Seventy-six of 156 FLCN mutation carriers (120 probands and 36 sibs, 48.7%) had skin papules; however, cutaneous manifestations were so subtle that only one patient voluntarily consulted dermatologists. Japanese Asian BHD families have three FLCN mutational hotspots. Recurrent episodes of pneumothoraces are the major symptoms suggestive of a BHD diagnosis in our cohort. Characteristic features of lung and kidney lesions may be more informative than fibrofolliculomas as diagnostic criteria for BHD in the Japanese Asian population.

Case Report of Birt-Hogg-Dubé Syndrome: Germline Mutations of FLCN Detected in Patients With Renal Cancer and Thyroid Cancer

Birt-Hogg-Dubé (BHD) is a rare autosomal dominant inherited syndrome that is characterized by the presence of fibrofolliculomas and/or trichodiscomas, pulmonary cysts, spontaneous pneumothorax, and renal tumors. Here, the 2 patients we reported with renal cell carcinomas and dermatological features were suspected to be suffering from BHD syndrome. Blood samples of these patients were sent for whole exon sequencing performed by Sanger sequencing. Eight mutations, including 5 mutations, which were mapped in noncoding region, 1 synonymous mutation, and 2 missense mutations, were detected in the FLCN gene in both patients. The 2 missense mutations, predicted to be disease-causing mutation or affecting protein function by MutationTaster and SIFT, confirmed the diagnosis. In addition, the 2 patients were also affected with papillary thyroid cancer. Total thyroidectomy and prophylactic bilateral central lymph node dissection were performed for them and the BHD-2 also received lateral lymph node dissection. Pathology reports showed that the patients had lymph node metastasis in spite of small size of thyroid lesions.The 2 missense mutations, not reported previously, expand the mutation spectrum of FLCN gene associated with BHD syndrome. For the thyroid cancer patients with BHD syndrome, total thyroidectomy and prophylactic bilateral central lymph node dissection may be suitable and the neck ultrasound may benefit BHD patients and their family members.

Diagnosis and Management of Hereditary Renal Cell Cancer

Renal cell cancer (RCC) is the common denominator for a heterogeneous group of diseases. The subclassification of these tumours is based on histological type and molecular pathogenesis. Insight into molecular pathogenesis has led to the development of targeted systemic therapies. Genetic susceptibility is the principal cause of RCC in about 2-4% of cases. Hereditary RCC is the umbrella term for about a dozen different conditions, the most frequent of which is von Hippel-Lindau disease . Here, we describe the main hereditary RCC syndromes, consider criteria for referral of RCC patients for clinical genetic assessment and discuss management options for patients with hereditary RCC and their at-risk relatives.