Clinical and genetic characteristics of 100 consecutive patients with Birt-Hogg-Dubé syndrome in Eastern Chinese region.

BACKGROUND: Although an increasing number of patients with Birt-Hogg-Dubé syndrome (BHD) are being recognized in China, clinical and genetic characteristics are not well-defined. In addition, revised diagnostic criteria for the Chinese population was proposed in 2023, we aimed to explore their utility in clinical practice at a rare lung disease center. METHODS: We retrospectively analyzed the data of 100 consecutive patients with BHD diagnosed according to the revised Chinese BHD criteria, encountered at the First Affiliated Hospital of University of Science and Technology of China from Jan 2017 to June 2023. RESULTS: There were 100 patients (including 63 females) from 65 unrelated families in Eastern China, mostly Anhui Province. The common manifestations were pulmonary cysts (99%), pneumothorax (60%), and skin lesions (77%). Renal cancer and renal angiomyolipoma were detected in 5 patients each. 37% of patients had no family history of BHD. In total, 25 FLCN germline mutations were detected, including 6 novel mutations. In addition to hotspot mutation c.1285delC/dupC (17%), the most common mutations were c.1015 C > T (16%), c.1579_1580insA (14%), and exons 1-3 deletion (11%) in FLCN. Higher risk of pneumothorax was associated with exons 1-3 deletion mutation and c.1177-5_1177-3de1CTC compared to the hotspot mutation c.1285dupC (91% [95% CI: 0.31, 46.82, p = 0.015] and 67% [95% CI: 0.35, 71.9, p = 0.302] vs. 30%, respectively). The average delay in diagnosis was 7.6 years after initial symptoms. Chinese diagnostic criteria were mostly consistent with typical pulmonary presentations with supportive genetic evidence. CONCLUSION: In the Eastern Chinese region, patients with BHD present most commonly with pulmonary cysts associated with pneumothorax and skin lesions. However, low incidence of renal cancer along with unexpected renal angiomyolipoma was observed. Genotypic spectrum differed from that reported from other global regions, and genotype association of pneumothorax warrants further research. The revised Chinese criteria for BHD seem more appropriate in diagnosing BHD in Chinese patients.

Minimally Invasive Plasma Device Management of Multiple Benign Skin Cancers Associated with Rare Genodermatoses-Case Series and Review of the Therapeutic Methods.

Background: Non-melanocytic benign skin tumours encompass a diverse group of lesions, classified based on their cellular origin, such as epidermal, vascular, fibrous, neural, muscle, and adnexal tumours. Though they often reveal solitary lesions, multiple skin tumours focus on genodermatoses. Each syndrome exhibits distinct clinical characteristics and potential complications, including cutaneous and extra-cutaneous malignancies, some of which are potentially life-threatening. Diagnosing genetic syndromes is complex and requires numerous histopathological and immunohistochemistry tests due to similarities between the adnexal tumours and basal cell carcinoma upon pathology. Methods: To illustrate the clinical practice, we conducted a retrospective case study that included eleven patients with genodermatoses referred to a tertiary dermatology clinic from September 2018 to April 2024. We have also conducted a research study on available treatment modalities in this setting. Results: Five patients with excellent aesthetic results were treated using a recently approved FDA plasma device. After searching SCOPUS and PubMed database records, we assessed 96 original articles to present current knowledge regarding the dermato-surgical approach. Conclusions: Multiple skin tumours, especially on the face, may significantly affect patients' quality of life and have psychological consequences. An appropriate treatment selection tailored to the patient's needs should be provided. There is no standardised treatment for multiple benign tumours in genodermatoses, and selected methods with varying efficacy are employed. We presented the utility of a new plasma device in these settings.

Diffuse Cystic Lung Disease: A Clinical Guide to Recognition and Management.

TOPIC IMPORTANCE: Diffuse cystic lung diseases (DCLDs) represent a group of pathophysiologically heterogeneous entities that share a common radiologic phenotype of multiple thin-walled pulmonary cysts. DCLDs differ from the typical fibroinflammatory interstitial lung diseases in their epidemiology, clinical presentation, molecular pathogenesis, and therapeutic approaches, making them worthy of a distinct classification. The importance of timely and accurate identification of DCLDs is heightened by the impact on patient management including recent discoveries of targeted therapeutic approaches for some disorders. REVIEW FINDINGS: This article offers a practical framework for evaluating patients with DCLD, indicating the most appropriate and current diagnostic and management approaches. We focus on the DCLDs that are most likely to be encountered by practicing pulmonologists: lymphangioleiomyomatosis, pulmonary Langerhans cell histiocytosis, Birt-Hogg-Dubé syndrome, and lymphoid interstitial pneumonia. Chest CT scan is the most informative noninvasive diagnostic modality to identify DCLDs. Thereafter, instituting a structured approach to high-yield associated factors (eg, medical, social, and family history; renal and dermatologic findings) increases the likelihood of identifying DCLDs and achieving a diagnosis. SUMMARY: Although the individual diseases that comprise the DCLD family are rare, taken together, DCLDs can be encountered more frequently in clinical practice than commonly perceived. An increased eagerness among general pulmonary physicians to recognize these entities, coupled with a practical and systematic clinical approach to examinations and investigations, is required to improve case findings, allow earlier intervention, and reduce morbidity and mortality.

Advances in Molecular Mechanisms of Kidney Disease: Integrating Renal Tumorigenesis of Hereditary Cancer Syndrome.

Renal cell carcinoma (RCC) comprises various histologically distinct subtypes, each characterized by specific genetic alterations, necessitating individualized management and treatment strategies for each subtype. An exhaustive search of the PubMed database was conducted without any filters or restrictions. Inclusion criteria encompassed original English articles focusing on molecular mechanisms of kidney cancer. On the other hand, all non-original articles and articles published in any language other than English were excluded. Hereditary kidney cancer represents 5-8% of all kidney cancer cases and is associated with syndromes such as von Hippel-Lindau syndrome, Birt-Hogg-Dubè syndrome, succinate dehydrogenase-deficient renal cell cancer syndrome, tuberous sclerosis complex, hereditary papillary renal cell carcinoma, fumarate hydratase deficiency syndrome, BAP1 tumor predisposition syndrome, and other uncommon hereditary cancer syndromes. These conditions are characterized by distinct genetic mutations and related extra-renal symptoms. The majority of renal cell carcinoma predispositions stem from loss-of-function mutations in tumor suppressor genes. These mutations promote malignant advancement through the somatic inactivation of the remaining allele. This review aims to elucidate the main molecular mechanisms underlying the pathophysiology of major syndromes associated with renal cell carcinoma. By providing a comprehensive overview, it aims to facilitate early diagnosis and to highlight the principal therapeutic options available.

Birt-Hogg-Dubé syndrome presenting with bilateral pneumothorax, skin, kidney, liver, and brain lesions.

Birt-Hogg-Dubé syndrome (BHDS) is a rare hereditary autosomal dominant condition characterized by benign cutaneous lesions, lung cysts, and increased risk of spontaneous pneumothorax and renal cancer. We report a case of a young Indian boy with bilateral pneumothorax as the first symptom of BHDS. Detailed history examination and investigation showed multiple facial lesions; his computerized tomography was suggestive of renal angiomyolipoma, hepatic angiomyolipoma, pulmonary cyst with pneumothorax, and small bilateral subependymal soft tissue density lesion with calcification in the brain, all of which were collectively suggestive of BHDS. Identification of the above commonly presented clinical features as a syndrome is important for even a primary care physician so as to ensure the timely management and if required referral to a higher center.

A Possible Association of Salivary Gland Tumors and Oral Lesions with Birt-Hogg-Dube Syndrome: A Systematic Review.

BACKGROUND: Birt-Hogg-Dube syndrome (BHDS) is an autosomal dominant syndrome with different skin, lung, and renal manifestations. It is diagnosed commonly in the third decade of life, and patients have an increased risk for pneumothorax and renal carcinomas. METHODS: Articles published in PubMed, and Medline from 1977 to September 2023, were included in the systematic review. Inclusion criteria were applied to case reports, case series, and a retrospective cohort study, describing clinical, histopathological, and genetic findings in patients with BHDS with oral and/or parotid lesions. RESULTS: Sixteen families/individuals with BHDS were identified for analysis. Patients ranged in age from 20 to 74 years, with an average of 49.4 years. Males were affected 52.2% of the time and females, 39.1%. Skin fibrofolliculomas were reported in 87% of cases, and oral lesions were documented in 47.8%. Parotid tumors were documented in 43.5% of patients, 30.4% of which were oncocytomas, 4.3% bilateral oncocytomas, and 4.3% "oncocytic carcinoma". CONCLUSIONS: Because BHDS is uncommon, its spectrum of clinical manifestations may be underrecognized, especially as the disease is mostly reported at advanced stage. And some of the patients with BHDS may have oncocytic parotid tumors and oral lesions. In this regard, patients presenting these lesions and other indications of BHDS should be considered for renal screening.

A 23-year bibliometric analysis of the development of global research on hereditary renal carcinoma.

Objectives: Medical research continues to be extensively devoted to investigating the pathogenesis and treatment approaches of hereditary renal cancer. By aspect including researchers, institutions, countries, journals, and keywords, we conduct a bibliometric analysis of the literature pertaining to hereditary renal cancer over the last 23 years. Methods: From the Web of Science Core Collection, we conducted a search for publications published between January 1, 2000 and November 28, 2023. Reviews and original articles were included. Results: A cumulative count of 2,194 publications met the specified criteria for inclusion. The studies of the included articles involved a collective of 2,402 institutions representing 80 countries. Notably, the United States exhibited the highest number of published documents, constituting approximately 45.49% of the total. The preeminent institution in this discipline is the National Cancer Institute (NCI), which maintains a publication volume of 8.98%. In addition to being the most prolific author (125 publications), Linehan WM's works received the highest number of citations (11,985). In a comprehensive count, 803 journals have published related articles. In the top 10 most recent occurrences were the terms "hereditary leiomyomatosis" and "fumarate hydratase." Conclusion: This is the first bibliometric analysis of the literature on hereditary renal cancer. This article offers a thorough examination of the present status of investigations concerning hereditary renal cancer during the previous 23 years.

A retrospective cohort study of genetic referral and diagnosis of Birt-Hogg-Dubé Syndrome in patients with Trichodiscoma and Fibrofolliculoma skin lesions.

BACKGROUND: Birt-Hogg-Dubé (BHD) syndrome is a genetic condition caused by pathogenic variants in the FLCN gene resulting in benign skin lesions, spontaneous pneumothorax, and increased risk for a variety of renal tumors. Skin manifestations of BHD include trichodiscoma (TD) and fibrofolliculoma (FF), which may represent the same pathologic entity. These lesions can identify BHD patients, who upon positive genetic testing can be considered for life-long surveillance for renal neoplasms. OBJECTIVE: To characterize patients diagnosed with TD and FF including rates and outcomes of genetics referral. METHODS: Retrospective chart reviews of patients with confirmed or possible diagnosis of TD or FF at the University of Michigan from September 2002 through October 2020 to assess pathologic findings, personal and family history of BHD manifestations, referral for genetic evaluation, and genetic testing results. RESULTS: 64 patients had a pathologic diagnosis of TD or FF, 16 of whom (25%) were referred to cancer genetics. Fourteen patients completed genetic evaluation, 9 of whom were diagnosed with BHD (64%), with 6 unique pathogenic variants in FLCN. CONCLUSION: Providers should consider referral for genetic evaluation for patients with biopsy-proven TD or FF, as early diagnosis of BHD provides the opportunity for early detection and treatment of other BHD-associated conditions.

Urticarial vasculitis and systemic symptoms as initial presentation of Birt-Hogg-Dubé syndrome: A case report.

Birt-Hogg-Dubé syndrome, an extremely rare genetic disorder, is characterized by the development of fibrofolliculomas, lung cysts and subsequent recurrent pneumothorax, and kidney neoplasia. This report highlights the case of a 56-year-old female with a history of right vestibular schwannoma status post stereotactic radiotherapy and vulva bartholin's gland carcinoma who was initially evaluated by primary care for a 6-month history of intermittent, red, raised, widespread rash accompanied by fever, chills, and body aches. A punch biopsy of the rash was performed, which was notable for an urticarial tissue reaction with focal changes of leukocytoclasia and negative direct immunofluorescence. Laboratory tests, which included an autoimmune genetic and periodic fever panel, were unremarkable. Whole genome sequencing returned positive for a pathogenic variant in folliculin gene, consistent with a diagnosis of Birt-Hogg-Dubé syndrome.

Tumores renales múltiples y hereditarios. Revisión por y para radiólogos / Multiple and hereditary renal tumors: A review for radiologists

El 80% de los carcinomas renales (CR) se diagnostican incidentalmente por imagen. Se aceptan un 2-4% de multifocalidad «esporádica» y un 5-8% de síndromes hereditarios, probablemente con infraestimación. Multifocalidad, edad joven, historia familiar, datos sindrómicos y ciertas histologías hacen sospechar un síndrome hereditario. Debe estudiarse individualmente cada tumor y multidisciplinarmente al paciente, con estrategias terapéuticas conservadoras de nefronas y un abordaje diagnóstico radioprotector. Se revisan los datos relevantes para el radiólogo en los síndromes de von Hippel-Lindau, translocación de cromosoma-3, mutación de proteína-1 asociada a BRCA, CR asociado a déficit en succinato-deshidrogenasa, PTEN, CR papilar hereditario, cáncer papilar tiroideo-CR papilar, leiomiomatosis hereditaria y CR, Birt-Hogg-Dubé, complejo esclerosis tuberosa, Lynch, translocación Xp11.2/fusión TFE3, rasgo de células falciformes, mutación DICER1, hiperparatoridismo y tumor mandibular hereditario, así como los principales síndromes de predisposición al tumor de Wilms.(AU)

80% of renal carcinomas (RC) are diagnosed incidentally by imaging. 2-4% of “sporadic” multifocality and 5-8% of hereditary syndromes are accepted, probably with underestimation. Multifocality, young age, familiar history, syndromic data, and certain histologies lead to suspicion of hereditary syndrome. Each tumor must be studied individually, with a multidisciplinary evaluation of the patient. Nephron-sparing therapeutic strategies and a radioprotective diagnostic approach are recommended. Relevant data for the radiologist in major RC hereditary syndromes are presented: von-Hippel-Lindau, Chromosome-3 translocation, BRCA-associated protein-1 mutation, RC associated with succinate dehydrogenase deficiency, PTEN, hereditary papillary RC, Papillary thyroid cancer- Papillary RC, Hereditary leiomyomatosis and RC, Birt-Hogg-Dubé, Tuberous sclerosis complex, Lynch, Xp11.2 translocation/TFE3 fusion, Sickle cell trait, DICER1 mutation, Hereditary hyperparathyroidism and jaw tumor, as well as the main syndromes of Wilms tumor predisposition. The concept of “non-hereditary” familial RC and other malignant and benign entities that can present as multiple renal lesions are discussed.(AU)

Multiple and hereditary renal tumors: a review for radiologists.

80% of renal carcinomas (RC) are diagnosed incidentally by imaging. 2-4% of "sporadic" multifocality and 5-8% of hereditary syndromes are accepted, probably with underestimation. Multifocality, young age, familiar history, syndromic data, and certain histologies lead to suspicion of hereditary syndrome. Each tumor must be studied individually, with a multidisciplinary evaluation of the patient. Nephron-sparing therapeutic strategies and a radioprotective diagnostic approach are recommended. Relevant data for the radiologist in major RC hereditary syndromes are presented: von-Hippel-Lindau, Chromosome-3 translocation, BRCA-associated protein-1 mutation, RC associated with succinate dehydrogenase deficiency, PTEN, hereditary papillary RC, Papillary thyroid cancer- Papillary RC, Hereditary leiomyomatosis and RC, Birt-Hogg-Dubé, Tuberous sclerosis complex, Lynch, Xp11.2 translocation/TFE3 fusion, Sickle cell trait, DICER1 mutation, Hereditary hyperparathyroidism and jaw tumor, as well as the main syndromes of Wilms tumor predisposition. The concept of "non-hereditary" familial RC and other malignant and benign entities that can present as multiple renal lesions are discussed.

The Prevalence and Radiologic Features of Renal Cancers Associated with FLCN, BAP1, SDH, and MET Germline Mutations.

Purpose To investigate the prevalence of FLCN, BAP1, SDH, and MET mutations in an oncologic cohort and determine the prevalence, clinical features, and imaging features of renal cell carcinoma (RCC) associated with these mutations. Secondarily, to determine the prevalence of encountered benign renal lesions. Materials and Methods From 25 220 patients with cancer who prospectively underwent germline analysis with a panel of more than 70 cancer-predisposing genes from 2015 to 2021, patients with FLCN, BAP1, SDH, or MET mutations were retrospectively identified. Clinical records were reviewed for patient age, sex, race/ethnicity, and renal cancer diagnosis. If RCC was present, baseline CT and MRI examinations were independently assessed by two radiologists. Summary statistics were used to summarize continuous and categorical variables by mutation. Results A total of 79 of 25 220 (0.31%) patients had a germline mutation: FLCN, 17 of 25 220 (0.07%); BAP1, 22 of 25 220 (0.09%); SDH, 39 of 25 220 (0.15%); and MET, one of 25 220 (0.004%). Of these 79 patients, 18 (23%) were diagnosed with RCC (FLCN, four of 17 [24%]; BAP1, four of 22 [18%]; SDH, nine of 39 [23%]; MET, one of one [100%]). Most hereditary RCCs demonstrated ill-defined margins, central nonenhancing area (cystic or necrotic), heterogeneous enhancement, and various other CT and MR radiologic features, overlapping with the radiologic appearance of nonhereditary RCCs. The prevalence of other benign solid renal lesions (other than complex cysts) in patients was up to 11%. Conclusion FLCN, BAP1, SDH, and MET mutations were present in less than 1% of this oncologic cohort. Within the study sample size limits, imaging findings for hereditary RCC overlapped with those of nonhereditary RCC, and the prevalence of other associated benign solid renal lesions (other than complex cysts) was up to 11%. Keywords: Familial Renal Cell Carcinoma, Birt-Hogg-Dubé Syndrome, Carcinoma, Renal Cell, Paragangliomas, Urinary, Kidney © RSNA, 2024.

A case report of Birt-Hogg-Dubé syndrome associated with severe airway obstruction in a 62-year-old female smoker.

Birt-Hogg-Dubé syndrome (BHD) typically does not manifest airway obstruction despite the presence of multiple lung cysts. However, the long-term effects of cigarette smoking on lung function among individuals with BHD are unknown. We report a case of a smoking individual diagnosed with BHD syndrome complicated by spontaneous pneumothorax and severe airway obstruction. The patient presented with chronic dyspnea and productive cough. Further work-up revealed severe obstructive airflow limitation, and multiple lung cysts in both lungs, accompanied centrilobular emphysematous changes. Genetic testing confirmed a heterozygous deletion of exons 6-8 in the folliculin gene, confirming the diagnosis of BHD.

Familial pulmonary cysts: A clue to diagnose Birt-Hogg-Dubé syndrome: A case report and literature review.

Birt-Hogg-Dubé syndrome (BHD) is an inherited autosomal dominant condition caused by germline mutations in the FLCN gene, mapped to chromosome 17p11.2. Typical manifestations include pulmonary cysts, spontaneous pneumothorax, fibrofolliculomas, and kidney neoplasms. This report details the case of a 56-year-old female non-smoker diagnosed with multiple pulmonary cysts, presenting with a history of recurrent spontaneous pneumothorax. A computed tomography (CT) scan of her daughter revealed similar pulmonary cysts, raising suspicion of BHD. Further abdominal enhanced CT revealed a left renal tumour and cutaneous fibrofolliculomas on her daughter's neck. Consequently, whole-exome sequencing confirmed an FLCN germline mutation in the patient and three relatives, establishing a diagnosis of BHD. This case highlights the importance of familial pulmonary cysts as a clue for diagnosing BHD, providing crucial insights into comparable clinical presentations.

An elderly woman with Birt-Hogg-Dubé syndrome having multiple pulmonary cysts mimicking lymphangioleiomyomatosis.

The characteristics of the pulmonary cysts on the high-resolution computed tomography (HRCT) chest images are an important diagnostic clue to distinguish among cystic lung diseases. The diagnostic accuracy of HRCT was reported to be as high as 90% by experienced pulmonologists and radiologists. Herein, we report the case of an elderly woman with Birt-Hogg-Dubé syndrome (BHDS) whose HRCT images displayed lymphangioleiomyomatosis-like features of the pulmonary cysts, rendering it difficult for us to diagnose BHDS. This case illustrates the significance of a thorough anamnesis, physical examination, and skin biopsy of facial papules to establish an accurate diganosis.

Hereditary Renal Cancer Syndromes.

Familial kidney tumors represent a rare variety of hereditary cancer syndromes, although systematic gene sequencing studies revealed that as many as 5% of renal cell carcinomas (RCCs) are associated with germline pathogenic variants (PVs). Most instances of RCC predisposition are attributed to the loss-of-function mutations in tumor suppressor genes, which drive the malignant progression via somatic inactivation of the remaining allele. These syndromes almost always have extrarenal manifestations, for example, von Hippel-Lindau (VHL) disease, fumarate hydratase tumor predisposition syndrome (FHTPS), Birt-Hogg-Dubé (BHD) syndrome, tuberous sclerosis (TS), etc. In contrast to the above conditions, hereditary papillary renal cell carcinoma syndrome (HPRCC) is caused by activating mutations in the MET oncogene and affects only the kidneys. Recent years have been characterized by remarkable progress in the development of targeted therapies for hereditary RCCs. The HIF2aplha inhibitor belzutifan demonstrated high clinical efficacy towards VHL-associated RCCs. mTOR downregulation provides significant benefits to patients with tuberous sclerosis. MET inhibitors hold promise for the treatment of HPRCC. Systematic gene sequencing studies have the potential to identify novel RCC-predisposing genes, especially when applied to yet unstudied populations.

Folliculin gene-negative Birt-Hogg-Dube syndrome: a case report.

Introduction and importance: Birt-Hogg-Dube (BHD) is a rare genetic disorder that results from a mutation in the folliculin (FLCN) gene. Manifestations include pulmonary cysts, fibrofolliculomas, renal tumors, and pneumothoraces. Genetic testing can be used to confirm the diagnosis when suspected. BHD syndrome is diagnosed in patients with negative FLCN gene results using diagnostic criteria. Case presentation: A male in his 20s presented with recurrent pneumothoraces. A physical examination revealed bumps on his face and upper body. A chest computed tomography scan revealed cystic lesions. Blood tests, ESR, and CRP levels were unremarkable. Punch skin biopsy revealed fibrofolliculomas. Genetic testing for the FLCN mutation returned negative. His history, physical exam, imaging, and histopathology suggested BHD syndrome despite having a negative family history and genetic analysis. Eventually, the patient was diagnosed with FLCN gene-negative BHD syndrome. Clinical discussion: More than a hundred families have been identified to have BHD worldwide. There are a few cases in the literature describing patients phenotypically presenting with BHD despite having a negative genetic analysis. One study in Japan found 16 out of 157 individuals having a clinical presentation of BHD with no mutations. Also, decreased expression of the FLCN mRNA may lead to BHD. Conclusion: BHD syndrome can present with a negative FLCN gene mutation; however, patients must meet the known diagnostic criteria such as criteria made by Menko et al., Gupta et al., and Schmidt et al. in order to have a diagnosis of BHD syndrome. Also, a qualitative decrease of FLCN with the absence of mutations may also lead to BHD.

Birt-Hogg-Dubé syndrome in an overall view: Focus on the clinicopathological prospects in renal tumors.

Birt-Hogg-Dubé syndrome (BHD) represents a rare autosomal dominant tumor predisposition syndrome characterized by skin lesions, lung cysts, and renal tumors. The predominant histological subtypes of BHD-related renal tumors include hybrid oncocytoma-chromophobe tumors, oncocytomas, and chromophobe renal cell carcinomas, all exhibiting eosinophilic/oncocytic features. Immunohistochemistry staining for KIT (CD117) and CK7 exhibits variability in these tumor types. Germline mutations in FLCN have been consistently identified. Generally, patients with BHD demonstrate a favorable prognosis with minimal metastatic potential. Nonetheless, the comprehensive elucidation of pathological characteristics of BHD remains incomplete, particularly in BHD-associated renal tumors that deviate from the previously identified subtypes, thereby complicating the differential diagnosis. In this review, we provide a comprehensive overview of BHD encompassing epidemiology, clinical manifestations, genetic and molecular pathogenesis, as well as clinical diagnostic modalities. Emphasis is placed on clinicopathological features, specifically focusing on BHD-associated renal tumors. Collectively, this review aims to present the latest insights into BHD which benefits in the early detection, therapeutic decision-making, and prognosis prediction in BHD cases, and deepen the understanding of sporadic renal tumors.

What is in a name-Perifollicular fibroma or fibrofolliculoma?

So far, confusion exists regarding the question of whether hereditary perifollicular fibromas and fibrofolliculomas can be distinguished from each other. Here, histopathological arguments are presented to clarify this terminological problem. In 1977, Birt et al. described a large kindred affected with hereditary multiple "fibrofolliculomas," which they thought were "a hitherto unrecognized pilar hamartoma," but they never claimed the fibrofolliculomas were part of a syndrome. A careful microscopic comparison shows, however, that the tumors are clinically and histopathologically identical to perifollicular fibromas, as first described by Burnier and Rejsek in 1925. Their familial occurrence was discovered in 1971 by Civatte and Le Tréguilly. Before 1977, the term "perifollicular fibroma" was used for these skin tumors. By contrast, Hornstein and Knickenberg described in 1975 perifollicular fibromas as a cutaneous marker of a syndrome characterized by a predisposition to colon cancer and pneumothorax. Later, two French groups erroneously proposed the term "Birt-Hogg-Dubé syndrome" to describe the co-occurrence of fibrofolliculomas, trichodiscomas, and acrochordons, which was contrary to what Birt et al. had in mind. Hence, today, we should discriminate between the hereditary nonsyndromic perifollicular fibromas, as documented by Civatte and Le Tréguilly and later by Birt et al., and the syndromic perifollicular fibromas, as delineated by Hornstein and Knickenberg.