Birt-Hogg-Dubé syndrome: A review of the literature and the differential diagnosis of firm facial papules

Adnexal neoplasms of the eye

Adnexal neoplasms of the eyelid encompass a wide variety of benign and malignant tumors of sebaceous, follicular, and sweat gland origin. Due to the specialized structures of the eyelid, these neoplasms present differently when compared with those of other locations. Although most dermatologists and ophthalmologists are familiar with the commonly reported adnexal tumors of the eyelid, such as hidrocystoma, pilomatrixoma, and sebaceous carcinoma, many other adnexal neoplasms have been reported at this unique anatomic site. Accurate and timely identification of these neoplasms is essential, as alterations of eyelid anatomy and function can have a negative impact on eye health, vision, and quality of life. We review the clinical and histopathologic features of common and rare eyelid adnexal neoplasms and discuss proposed treatment options.

Familial multiple discoid fibromas is linked to a locus on chromosome 5 including the FNIP1 gene

Previously, we reported a series of families presenting with trichodiscomas, inherited in an autosomal dominant pattern. The phenotype was named familial multiple discoid fibromas (FMDF). The genetic cause of FMDF remained unknown so far. Trichodiscomas are skin lesions previously reported to be part of the same spectrum as the fibrofolliculoma observed in Birt-Hogg-Dubé syndrome (BHD), an inherited disease caused by pathogenic variants in the FLCN gene. Given the clinical and histological differences with BHD and the exclusion of linkage with the FLCN locus, the phenotype was concluded to be distinct from BHD. We performed extensive clinical evaluations and genetic testing in ten families with FMDF. We identified a FNIP1 frameshift variant in nine families and genealogical studies showed common ancestry for eight families. Using whole exome sequencing, we identified six additional rare variants in the haplotype surrounding FNIP1, including a missense variant in the PDGFRB gene that was found to be present in all tested patients with FMDF. Genome-wide linkage analysis showed that the locus on chromosome 5 including FNIP1 was the only region reaching the maximal possible LOD score. We concluded that FMDF is linked to a haplotype on chromosome 5. Additional evaluations in families with FMDF are required to unravel the exact genetic cause underlying the phenotype. When evaluating patients with multiple trichodisomas without a pathogenic variant in the FLCN gene, further genetic testing is warranted and can include analysis of the haplotype on chromosome 5.

Comment on Balsamo et al.: Birt-Hogg-Dubé syndrome with simultaneous hyperplastic polyposis of the gastrointestinal tract: case report and review of the literature

The publication by Balsamo and colleagues describes a patient with Birt-Hogg-Dubé syndrome and hyperplastic polyposis throughout the gastro-intestinal tract. We question whether the diagnosis of BHD in this patient was justified. Using the previously proposed diagnostic criteria for establishing the diagnosis of BHD as a guideline, we systematically describe our concerns. In our opinion, the patient described by Balsamo and colleagues does not meet any of the proposed major and minor criteria for the diagnosis of Birt-Hogg-Dubé syndrome. Therefore, we believe that it is not justified to suggest a possible association between hyperplastic polyposis and Birt-Hogg-Dubé syndrome based on this patient, even though a higher risk for colorectal polyposis in Birt-Hogg-Dubé syndrome has not been excluded so far.

Renal Oncocytoma: The Diagnostic Challenge to Unmask the Double of Renal Cancer

Renal oncocytoma represents the most common type of benign neoplasm that is an increasing concern for urologists, oncologists, and nephrologists due to its difficult differential diagnosis and frequent overtreatment. It displays a variable neoplastic parenchymal and stromal architecture, and the defining cellular element is a large polygonal, granular, eosinophilic, mitochondria-rich cell known as an oncocyte. The real challenge in the oncocytoma treatment algorithm is related to the misdiagnosis due to its resemblance, at an initial radiological assessment, to malignant renal cancers with a completely different prognosis and medical treatment. Unfortunately, percutaneous renal biopsy is not frequently performed due to the possible side effects related to the procedure. Therefore, the majority of oncocytoma are diagnosed after the surgical operation via partial or radical nephrectomy. For this reason, new reliable strategies to solve this issue are needed. In our review, we will discuss the clinical implications of renal oncocytoma in daily clinical practice with a particular focus on the medical diagnosis and treatment and on the potential of novel promising molecular biomarkers such as circulating microRNAs to distinguish between a benign and a malignant lesion.

[Are multiple trichodiscomas/fibrofolliculomas the Birt-Hogg-Dubé syndrome?]

Birt-Hogg-Dubé syndrome is a rare autosomal dominant disease caused by a mutation in the FLCN gene and presents with a triad of multiple fibrofolliculomas, trichodiscomas, and masses that clinically resemble fibroepithelial polyps (acrochordones), accompanied by an increased risk of kidney tumors and lung cysts. The paper provides a literature review supplemented by clinical cases and the morphological pattern of skin lesions. It presents the clinical and morphological features of cutaneous manifestations of the syndrome and gives diagnostic criteria.

Birt-Hogg-Dubé syndrome

Birt–Hogg–Dubé syndrome (BHD) is a rare inherited autosomal dominant disorder caused by germline mutations in the tumour suppressor gene FLCN, encoding the protein folliculin. Its clinical expression typically includes multiple pulmonary cysts, recurrent spontaneous pneumothoraces, cutaneous fibrofolliculomas and renal tumours of various histological types. BHD has no sex predilection and tends to manifest in the third or fourth decade of life. Multiple bilateral pulmonary cysts are found on chest computed tomography in >80% of patients and more than half experience one or more episodes of pneumothorax. A family history of pneumothorax is an important clue, which suggests the diagnosis of BHD. Unlike other cystic lung diseases such as lymphangioleiomyomatosis and pulmonary Langerhans cell histiocytosis, BHD does not lead to progressive loss of lung function and chronic respiratory insufficiency. Renal tumours affect about 30% of patients during their lifetime, and can be multiple and recurrent. The diagnosis of BHD is based on a combination of genetic, clinical and/or skin histopathological criteria. Management mainly consists of early pleurodesis in the case of pneumothorax, periodic renal imaging for tumour detection, and diagnostic work-up in search of BHD in relatives of the index patient.

Birt–Hogg–Dubé syndrome is a rare genetic disorder characterised by multiple lung cysts, recurrent pneumothoraces, skin lesions and kidney tumours. As the presenting symptoms may be respiratory, chest physicians should be able to identify this disease.https://bit.ly/2xsOTuk

Conjunctival Trichodiscoma of the Lower Eyelid

Trichodiscomas are benign tumors of the skin which develop around a hair follicle. They usually present on the face, neck, or trunk region. The authors report a rare case of a 63-year-old man who presented with a tumor on the left lower eyelid that was histologically proven to be a trichodiscoma of conjunctival origin.Trichodiscomas are benign tumors of the skin appendage which develop around a hair follicle. Although conjunctival hair follicles are rudimentary and do not give rise to hair, rarely a benign proliferation of these cells can result in trichodiscoma of the conjunctiva.

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.

Birt-Hogg-Dubé syndrome: a case report and a review of the literature

Background: Birt-Hogg-Dubé syndrome (BHDS) is a rare autosomal dominant inherited syndrome caused by mutations in the folliculin coding gene (FLCN). The clinical manifestations of the syndrome involve the skin, lungs, and kidneys. Because of the rarity of the syndrome, guidelines for diagnosis and management of the patients with BHDS are lacking.

Objective: To present a case story and a review of the literature on BHDS in order to give an update on genetics, clinical manifestations, diagnosis, treatment, prognosis and follow-up strategies.

Design: Literature review and case story.

Results: A PubMed and Embase search identified 330 papers. BHDS is characterized by small benign tumors in the skin, spontaneous pneumothoraces caused by cysts in the lungs and a seven-fold increased risk of renal cancer. A case story of a young female patient presenting with pneumothorax and a family history of recurrent pneumothoraces in many relatives illustrates how the history and the diagnostic work up resulted in a diagnosis of BHDS.

Conclusion: BHDS is a rare inherited disorder. In patients with spontaneous pneumothorax or cystic lung disease without any obvious explanation, BHDS should be considered. Concomitant skin manifestations, a family history of familiar pneumothorax, renal cancers and skin manifestations supports the suspicion of BHDS. Early diagnosis is important in order to subject patients to systematic screening for renal cancers. A radiological surveillance strategy for renal cancer is proposed.

Birt-Hogg-Dubé Syndrome Presenting as a Nevus Comedonicus-Like Lesion in an 8-Year-Old Boy

Birt-Hogg-Dubé syndrome is an uncommon genodermatosis characterized by hair follicle hamartomas and an increased risk of pneumothorax and renal cell carcinoma. Recognition of cutaneous manifestations is essential because it allows for early screening and management of systemic complications. We present the case of an 8-year-old boy with a recently described cystic and comedonal variant of the classic fibrofolliculoma, which had been present since birth.

The spectrum of nephrocutaneous diseases and associations: Genetic causes of nephrocutaneous disease

There are a significant number of diseases and treatment considerations of considerable importance relating to the skin and renal systems. This emphasizes the need for dermatologists in practice or in clinical training to be aware of these associations. Part I of this 2-part continuing medical education article reviews the genetic syndromes with both renal and cutaneous involvement that are most important for the dermatologist to be able to identify, manage, and appropriately refer to nephrology colleagues. Part II reviews the inflammatory syndromes with relevant renal manifestations and therapeutic agents commonly used by dermatologists that have drug-induced effects on or require close consideration of renal function. In addition, we will likewise review therapeutic agents commonly used by nephrologists that have drug-induced effects on the skin that dermatologists are likely to encounter in clinical practice. In both parts of this continuing medical education article, we discuss diagnosis, management, and appropriate referral to our nephrology colleagues in the context of each nephrocutaneous association. There are a significant number of dermatoses associated with renal abnormalities and disease, emphasizing the need for dermatologists to be keenly aware of their presence in order to avoid overlooking important skin conditions with potentially devastating renal complications. This review discusses important nephrocutaneous disease associations with recommendations for the appropriate urgency of referral to nephrology colleagues for diagnosis, surveillance, and early management of potential renal sequelae.

A rare soft tissue tumor masquerading as a parathyroid adenoma in a patient with birt-hogg-dubé syndrome and multiple cervical endocrinopathies

Birt-Hogg-Dubé (BHD) syndrome is an autosomal dominant disorder that presents with renal tumors, pulmonary cysts with spontaneous pneumothoraces, and skin hamartomas. We present a case of a 67-year-old female with multiple endocrinopathies and a history of BHD syndrome. In 2011, a thyroidectomy with a four-gland parathyroidectomy was performed for toxic multinodular goiter (TMNG) and parathyroid hyperplasia. On frozen section, a tumor was identified next to a hypercellular parathyroid. After being worked up, this tumor was determined to be an adult rhabdomyoma. This represents the first time that both TMNG and parathyroid hyperplasia have been present in a BHD patient. Additionally, this is the first adult rhabdomyoma reported in a patient with BHD syndrome. Adult rhabdomyomas have no reported associations; however, potential colocation of the mutation in BHD syndrome and translocation in adult rhabdomyomas on chromosome 17p suggests a possible connection. Further work is needed to better understand this connection.

Syndrome of Birt-Hogg-Dubé, a histopathological pitfall with similarities to tuberous sclerosis: a report of three cases

Birt-Hogg-Dubé Syndrome (BHD) is a rare condition, transmitted as an autosomal-dominant trait. The etiology is due to a mutation in the BHD gene, which encodes folliculin (FLCN), located on chromosome 17p. The skin changes observed are benign skin tumors consisting of hamartomas of the hair follicle with dermal changes. Patients with BHD have an increased risk of spontaneous pneumothorax due to rupture of lung cysts and an increased risk of kidney tumors. We report 3 new cases of BHD and discuss their clinical features, histopathological findings, and molecular diagnostics. We highlight the importance of genetic analysis to confirm the diagnosis because of the clinical pitfalls involved in establishing a diagnosis. Finally, we discuss the histopathological features in BHD and tuberous sclerosis complex and focus on their overlapping criterias. A correct diagnosis is essential as it can be life saving for patients.

Pediatric bilateral spontaneous pneumothoraces in monozygotic twins

Primary spontaneous pneumothorax from subpleural bleb disease is an uncommon occurrence in pediatric patients. This is a rare case of monozygotic twins presenting at alternating intervals with a single-sided spontaneous pneumothorax, only to have it surgically corrected, and to present later with a subsequent contralateral pneumothorax. A review of familial spontaneous pneumothoraces occurring in children was queried for congenital or genetic syndromes. We concluded that a vast majority of pneumothoraces in children, like adults, are not spontaneous and not familial linked. While they are rare, some congenital syndromes have been identified. The HLA haplotype A2 B40, the gene encoding folliculin, Alph-1-antitrypsin, Marfan's syndrome, Ehlers-Danlos syndrome and Birt-Hogg-Dube syndrome have all been associated with familial spontaneous pneumothoraces. Physicians need to counsel family members to ensure appropriate observation and expedited treatment is not delayed.

Staged, open, no-ischemia nephron-sparing surgery for bilateral-multiple kidney tumors in a patient with birt-hogg-dubé syndrome

Hereditary kidney cancer patients with bilateral multiple kidney tumors represent challenges in the era of rapidly growing minimal invasive treatment techniques. Birt-Hogg-Dubé Syndrome (BHDS) is an autosomal dominant genodermatosis characterized by a triad of benign skin tumors (fibrofolliculomas, trichodiscomas, acrochordons) together with an increased risk of developing malignant renal tumors and pulmonary disease such as pneumothoraces and multiple lung cysts. The morbidity and mortality of the affected patients is determined by the presence of the kidney tumors, which tend to be multifocal and bilateral, as observed in other hereditary kidney cancer syndromes like von Hippel-Lindau disease, familial leiomyomatosis, and hereditary papillary renal cell carcinoma. Herein, a patient with BHDS, presenting with synchronous bilateral multiple kidney tumors, is reported. The report describes the management of kidney tumors with two-stage open nephron-sparing surgery in which the nonvascular clamping technique was utilized.

Skin lesions in hereditary endocrine tumor syndromes

OBJECTIVE

To review the main cutaneous manifestations of hereditary endocrine tumor syndromes and discuss currently known molecular mechanisms involved in their pathogenesis.

METHODS

On the basis of our collective experience and a comprehensive MEDLINE literature search of the English-language literature published between January 1957 and September 2010 using the search terms "skin," "cutaneous," "multiple endocrine neoplasia," "Carney complex," and "McCune-Albright syndrome," we reviewed the dermatologic findings in multiple endocrine neoplasia type 1 and type 2, Carney complex, and McCune-Albright syndrome.

RESULTS

Although the category of hereditary endocrine tumor syndromes consists of a broad spectrum of conditions, only the aforementioned few are prominently associated with cutaneous features. Because the cutaneous findings associated with these diseases are generally benign, they are often ignored or dismissed as ancillary findings in the context of severe systemic involvement. Accordingly, the pertinent literature is relatively scarce and often fails to provide a comprehensive insight about this issue. Nevertheless, timely recognition of such dermatologic manifestations may have a critical role in the early diagnosis and appropriate management of the related syndromes. Moreover, specific genotype-phenotype correlations may convey important prognostic implications.

CONCLUSION

Many physicians are unfamiliar with the cutaneous findings in the hereditary endocrine tumor syndromes described in this review. Nonetheless, knowledge of their existence can have a major role in establishing an early diagnosis of these syndromes and determining the patient's prognosis.

Birt-hogg-dubé syndrome, a rare case in Korea confirmed by genetic analysis

Simple benign tumors can present as part of a syndrome with substantial mortality. Fibrofolliculomas are benign skin tumors most often associated with the Birt-Hogg-Dubé syndrome (BHDS). The most life-threatening complication of this syndrome is renal cancer and other major features include multiple lung cysts and spontaneous pneumothorax. We present the case of a 54 year-old man with multiple flesh-colored papules on his face confirmed histologically as fibrofolliculomas. He had a history of recurrent pneumothorax and chest computed tomography showed multiple lung cysts. To confirm the diagnosis of BHDS, we conducted gene analysis that revealed a single nucleotide duplication in the folliculin (FLCN) gene (Exon 11, C.1285dupC). BHDS confirmed by the FLCN gene mutation is rarely reported in Korea. Appropriate investigation is recommended whenever a patient with benign skin tumors is encountered.

Genetic study in a case of birt-hogg-dubé syndrome

Birt-Hogg-Dubé syndrome (BHDS) is an autosomal dominantly inherited disorder characterized by multiple trichodiscomas, fibrofolliculomas, and acrocordons. There is also an increased risk of developing renal neoplasms and lung cysts/spontaneous pneumothorax. We present a 43-year-old man with multiple, 2~4 mm sized, dome-shaped, and skin-colored papules on his cheek and neck. On the basis of clinical finding and histopathologic examination on the cheek lesion, it was diagnosed as multiple trichodiscomas. Subsequently, molecular analysis revealed a mutation in the folliculin gene. We report a rare case of BHDS with a proved gene mutation.

Familial multiple discoid fibromas: a look-alike of Birt-Hogg-Dubé syndrome not linked to the FLCN locus

BACKGROUND

Previously, we proposed that familial multiple trichodiscomas (OMIM 190340) is distinct from Birt-Hogg-Dubé syndrome (BHD) (OMIM #135150). BHD is characterized by multiple fibrofolliculomas/trichodiscomas, lung cysts, pneumothorax, and renal cell cancer. Germline FLCN mutations can be detected in most but not all BHD families.

OBJECTIVE

We sought to evaluate familial multiple trichodiscomas at a clinical and genetic level. We now renamed this condition "familial multiple discoid fibromas" (FMDF) to emphasize the distinction from BHD.

METHODS

In 8 additional families with an autosomal dominant pattern of multiple discoid fibromas we assessed the clinical findings and the histopathological features of skin lesions. FLCN germline mutation analysis was completed in 7 families. In two of these families segregation analysis was performed using polymorphic DNA markers in and around the FLCN locus.

RESULTS

The clinical findings in FMDF are different from those in BHD with early onset of skin lesions, prominent involvement of the pinnae, and discoid fibromas without the follicular epithelial component characteristic of the fibrofolliculoma/trichodiscoma spectrum of BHD. In addition, there were no evident pulmonary or renal complications. In none of the families were pathogenic FLCN germline mutations identified. Using segregation analysis we could exclude involvement of the FLCN locus in the two kindreds tested.

LIMITATIONS

The prevalence of FMDF is presently unknown. The underlying gene defect has not yet been identified.

CONCLUSIONS

FMDF is clinically distinct from BHD and is not linked to the FLCN locus.

Clinical and genetic spectrum of Birt-Hogg-Dube syndrome patients in whom pneumothorax and/or multiple lung cysts are the presenting feature

BACKGROUND

Birt-Hogg-Dubé syndrome (BHDS) is an inherited autosomal genodermatosis characterised by fibrofolliculomas of the skin, renal tumours and multiple lung cysts. Genetic studies have disclosed that the clinical picture as well as responsible germline FLCN mutations are diverse.

OBJECTIVES

BHDS may be caused by a germline deletion which cannot be detected by a conventional genetic approach. Real-time quantitative polymerase chain reaction (qPCR) may be able to identify such a mutation and thus provide us with a more accurate clinical picture of BHDS.

METHODS

This study analysed 36 patients with multiple lung cysts of undetermined causes. Denaturing high performance liquid chromatography (DHPLC) was applied for mutation screening. If no abnormality was detected by DHPLC, the amount of each FLCN exon in genome was quantified by qPCR.

RESULTS

An FLCN germline mutation was found in 23 (63.9%) of the 36 patients by DHPLC and direct sequencing (13 unique small nucleotide alterations which included 11 novel mutations). A large genomic deletion was identified in two of the remaining 13 patients by qPCR (one patient with exon 14 deletion and one patient with a deletion encompassing exons 9 to 14). Mutations including genomic deletions were most frequently identified in the 3'-end of the FLCN gene including exons 12 and 13 (13/25=52.0%). The BHDS patients whose multiple cysts prompted the diagnosis in this study showed a very low incidence of skin and renal involvement.

CONCLUSIONS

BHDS is due to large deletions as well as small nucleotide alterations. Racial differences may occur between Japanese and patients of European decent in terms of FLCN mutations and clinical manifestations.

Renal cancer associated with recurrent spontaneous pneumothorax in Birt-Hogg-Dubé syndrome: a case report and review of the literature

Introduction

Birt-Hogg-Dubé syndrome is a rare genodermatosis characterized by hair follicle hamartomas, renal tumors and spontaneous pneumothorax. We present the case of a patient with pulmonary cysts and recurrent spontaneous pneumothorax. She had typical skin lesions, and was found to have a hybrid oncocytoma which was surgically excised.

Case presentation

A 60-year-old Caucasian woman had a 10-year history of cystic lung disease and recurrent spontaneous pneumothoraces. She was noted to have papular lesions over her face and forehead. The result of a biopsy showed these lesions to be fibrofolliculomas. A diagnosis of Birt-Hogg-Dubé syndrome was made and she was screened for renal tumors since these are a recognized association. A hybrid oncocytoma was detected which was surgically excised by partial nephrectomy.

Conclusion

It is important to consider a possible diagnosis of Birt-Hogg-Dubé syndrome in cases of recurrent pneumothorax. Affected individuals must be screened for renal tumors, a potentially lethal consequence of this syndrome.

Birt-Hogg-Dubé syndrome: diagnosis and management

Birt-Hogg-Dubé syndrome (BHD) is an autosomal dominant condition characterised clinically by skin fibrofolliculomas, pulmonary cysts, spontaneous pneumothorax, and renal cancer. The condition is caused by germline mutations in the FLCN gene, which encodes folliculin; the function of this protein is largely unknown, although FLCN has been linked to the mTOR pathway. The availability of DNA-based diagnosis has allowed insight into the great variation in expression of FLCN, both within and between families. Patients can present with skin signs and also with pneumothorax or renal cancer. Preventive measures are aimed mainly at early diagnosis and treatment of renal cancer. This Review gives an overview of current diagnosis and management of BHD.

A prospective study of cutaneous manifestations of spinal dysraphism from India

Recognition of cutaneous markers of spinal dysraphism is important to prevent the morbidity associated with underlying spinal anomalies. To investigate the frequency and type of cutaneous stigmata in different forms of spinal dysraphism and to assess the role of ultrasonography and/or magnetic resonance imaging in diagnosing spinal dysraphism at two pediatric dermatology tertiary care centers. Over a 4-year period, all pediatric patients presenting to the dermatology clinic with dorsal midline cutaneous stigmata were evaluated clinically and with imaging studies (radiography, ultrasonographic examination and magnetic resonance imaging/Doppler). Surgical interventions were planned in conjunction with neurosurgery and orthopedic specialists. On examination, 245 (4.2%) had 285 cutaneous stigmata. Of the 180 patients evaluated with radiography, ultrasonographic examination and magnetic resonance imaging, 50 patients (28%) had spinal dysraphism (with 64 cutaneous stigmata). The most common stigmata associated with occult spinal dysraphism were lipoma (10) and dimples (12) and in open spinal dysraphism lipomeningomyelocoele (10) and meningomyelocoele (10). Statistically, lipomeningomyelocoele/myelomeningocoele, atypical dimples and port-wine stains were most associated with spinal dysraphism (p < 0.001). In 80 children less than 6 months of age, radiography with ultrasonographic examination revealed an SD in 16, while magnetic resonance imaging was diagnostic in four cases. Ultrasonographic examination performed fairly well in children less than 6 months and in cases of flat cutaneous stigmata it missed only 5% of cases, but in cases with bulky overlying masses (lipoma, hemangioma) it missed 15% of cases.

Facial papules as a marker of internal malignancy

Facial papules (bumps) confront the general practitioner during every face-to-face meeting with the patient. Increased awareness and recognition of the facial papules that represent cutaneous signs of internal malignancy will allow an early, aggressive workup and treatment of any associated cancer. This article details the clinical presentation, etiology, pathologic findings, and associated malignancy for such presentations. A skin biopsy for histopathologic diagnosis is necessary to distinguish these clues to underlying malignancy from the numerous benign lesions that cause facial papules.

Dermatology for the general surgeon

Preparation of the patient with preexisting skin disease for surgery can be challenging. In addition to encountering the skin with nearly every procedure, the surgeon will also likely experience skin-related conundrums, concerns, and associated conditions in the preoperative, perioperative, or postoperative periods. These concerns are reviewed using best available evidence.

A case of Birt-Hogg-Dubé syndrome

Birt-Hogg-Dubé syndrome (BHDS) is an autosomal dominant genodermatosis characterized by cutaneous hair follicle tumors (fibrofolliculoma or trichodiscoma), pulmonary cysts, and increased risk of renal neoplasia. The genetic alteration for BHDS has been mapped to chromosome 17p12q11, and the gene in this region has been cloned and believed to be responsible for the BHDS. Mutations in the BHD gene (also known as FLCN) have been described in the patients with BHDS. We present a case of a 30-yr-old Korean woman with multiple mildly pruritic papules on her face and neck area. The patient had several firm, flesh-colored, dome-shaped, papular lesions measuring between 2 to 5 mm. Except for a history of pneumothorax her medical records were not remarkable. Mutation analysis of the BHD gene was performed, and a novel deletion mutation (p.F519LfsX17 [c.1557delT]) causing truncation of the gene product, folliculin, was found in the exon 14. The actual incidence of BHDS is unknown, but it is most likely underdiagnosed. So it is imperative that doctors recognize the skin lesions of BHDS and institute proper screening to detect other manifestations of the disease. Here, we report a case of BHDS with a novel mutation, which is the first report in Korea.

Renal cell carcinoma: Current status and emerging therapies

Renal cell carcinoma (RCC) accounts for about 3% of all adult malignancies and its incidence is increasing. Smoking, obesity, and end-stage renal disease are important risk factors. Localized RCC may be cured with surgical excision. However, over one-third of patients eventually develop metastatic disease. While chemotherapy and radiation therapy are relatively ineffective for RCC, immunotherapy modestly extends survival and may lead to tumor regression and long-term survival in a small minority of patients. Recently, research into the pathology of genetic syndromes associated with RCC has led to remarkable advances in our understanding of the pathogenesis of sporadic RCC. Rational therapeutic agents developed from this understanding have established new treatment paradigms for this disease.

Extensive acrochordons and pancreatic islet-cell tumors in tuberous sclerosis associated with TSC2 mutations

Acrochordons are frequently encountered benign skin lesions that may occasionally represent underlying pathology. Pancreatic islet-cell tumors are rare neoplasms and few cases have been described in patients with tuberous sclerosis complex (TSC). A 39-year-old man presenting in acute renal failure was referred to us for further diagnostic evaluation of coincidentally noted dysmorphic features. Physical examination revealed over 1,000 acrochordons in addition to findings meeting criteria for TSC. The diagnosis was confirmed by disclosure of mutation in the TSC2 gene. Further evaluation revealed pancreatic islet cell tumors. Acrochordons are a common skin lesion, but when presenting in an atypical manner or unusual number may be a sign of TSC and underlying occult pathology thereby warranting evaluation of TSC2. Additionally, mutations in TSC2 gene may be a risk factor for developing pancreatic islet-cell tumors.