Hemoptysis after COVID-19 and the importance of differential diagnosis: Birt-Hogg-Dubé syndrome / Hemoptisis luego de COVID-19 y la importancia de los diagnósticos diferenciales: Síndrome de Birt-Hogg-Dubé

Abstract Birt-Hogg-Dubé syndrome is a genodermatosis of auto somal dominant inheritance characterized by mutations in the folliculin (FLCN) gene. There is an inappropriate inhibition/activation of a protein, the foliculin, which may cause tumor lesions in skin, renal and lung lesions; they could have more risk of developing pneumothorax compared to the normal population. A 38-year-old male patient with bronchial asthma who consulted for hemop tysis three weeks after recovery from COVID-19 infection. A chest tomography was requested, showing an air cyst in the left lower lobe. Physical examination shows evi dence of thoracic skin lesions which a skin biopsy was performed on. The results were compatible with fibrofol liculoma. Differential diagnoses were proposed. A genetic disorder associated with skin lesions was suspected. A multi-genetic panel that includes BRCA1, BRCA2, TP53 and FLCN genes was requested, which reported the mu tation of the FLCN gene in heterozygosis classified as pathognomonic of Birt-Hogg-Dubé syndrome. Patient is currently under clinical follow-up while genetic counsel ing was requested for relatives.

Resumen El síndrome de Birt-Hogg-Dubé es una genoderma tosis de herencia autosómica dominante caracterizada por mutaciones en el gen foliculina (FLCN), donde existe inhibición/activación inapropiada de una proteína, la foliculina, que puede causar lesiones tumorales sisté micas, principalmente a nivel de la piel, renal y lesiones pulmonares, presentando mayor riesgo de desarrollar neumotórax en comparación con la población normal. Comunicamos el caso de un varón de 38 años con asma bronquial que consultó por hemoptisis 3 semanas des pués de la recuperación de la infección por COVID-19. Se solicitó una tomografía de tórax, que mostró un quiste aéreo en el lóbulo inferior izquierdo. Además, presentaba en el examen físico una lesión cutánea que fue biopsiada, presentando diagnóstico de foliculoma. Se plantearon diagnósticos diferenciales y ante la sospecha de probable desorden genético, un panel genético fue solicitado. Se confirmó síndrome de Birt-Hogg-Dubé ante el hallazgo de la deleción heterocigota que comprende el exón 1 del gen FLCN clasificada como patogénica. Actual mente el paciente se encuentra en seguimiento clínico mientras se solicitó estudio genético para familiares.

Síndrome de Birt-Hogg-Dubé: afectación pulmonar en 2 casos / Birt-Hogg-Dubé Syndrome: Lung Involvement in 2 Cases

El síndrome de Birt-Hogg-Dubé es una rara enfermedad autosómica dominante causada por la mutación patogénica del gen de la foliculina, que se expresa principal mente en tres órganos que incluyen el pulmón, la piel y el riñón, y produce quistes pulmonares, tumores renales y cutáneos. Desde el punto de vista respiratorio es poco sintomática, pero los quistes presentan alto riesgo de neumotórax, por lo que es imprescindible realizar una adecuada semiología radiológica de los quistes para un diagnóstico oportuno. Los tumores más importantes son los renales porque incluyen varios tipos de carcinomas renales; debido a esto requieren seguimiento estricto y, en muchos, casos cirugía. Presentamos dos casos de pacientes con este síndrome; uno confirmado por la mutación genética y el otro, por la confirmación histológica de fibrofoliculoma, ambos criterios mayores para el diagnóstico de esta enfermedad. Es fundamental el diagnóstico temprano de esta entidad de acuerdo con lo expuesto anteriormente, por lo que hacemos esta revisión con una amplia discusión sobre la afectación pulmonar, la semiología radiológica de los quistes y los criterios diagnósticos.

The Birt-Hogg-Dubé syndrome is a rare autosomal dominant disease caused by the pathogenic mutation of the folliculin gene, which is mainly expressed in three organs that include the lung, the skin and the kidney, and produces lung cysts, and renal and skin tumors. From the respiratory point of view, it doesn't have many symptoms, but cysts have high risk of pneumothorax, so it is indispensable to carry out the correct radiological semiology of the cysts for a timely diagnosis. The most important tumors are the renal, because they include several types of renal carcinomas; that is why they require strict follow-up and, in many cases, surgery. We present two cases of patients with this syndrome: one confirmed by the genetic mutation, and the other one by the histological confirmation of fibrofolliculoma, both major criteria for the diagnosis of this disease. The early diagnosis of this entity is of fundamental importance, according to what has been previously presented, so we conduct this review with a broad discus sion about lung involvement, the radiological semiology of the cysts, and diagnostic criteria.

A case report of familial renal cell carcinoma / 中华泌尿外科杂志

A total of 4 patients with renal cancer were admitted to our hospital from October 2006 to September 2015 in a familial renal cancer family. Among the 4 patients, 1 patient showed unilateral multiple clear cell carcinoma, 1 patient showed bilateral multiple clear cell carcinoma, and 2 patients showed bilateral multiple chromophobe cell carcinoma. No mutation of VHL or FLCN gene was found in all patients by genetic analysis.

Solitary fibrofolliculoma: a retrospective case series review over 18 years / Fibrofoliculoma solitário: revisão de série retrospectiva de casos de 18 anos

ABSTRACT Purpose: The purpose of this study was to report a series of cases of solitary fibrofolliculoma, a lesion seldom observed in the lids. Demographics, as well as clinical and histological aspects of the lesion were evaluated. Methods: This was a retrospective case series spanning a period of 18 years. All the included patients were diagnosed with solitary fibrofolliculoma confirmed by histological examination. Data regarding patient demographics, signs, and symptoms, course of the disease, location of the lesion, clinical and histological diagnosis, and outcome were collected. Results: Eleven cases of solitary fibrofolliculoma were diagnosed in the study period. The median age of patients was 51 ± 16.3 years (range: 27-78 years). Most patients were females (7/11; 64%). Five of the patients (45%) were asymptomatic; four (36%) reported bleeding, one (9%) had referred itching, and one (9%) rubbing of the lesion. The lesion occurred in a wide range of locations; one of them was located in the lids. The diagnosis for all lesions was histological based on characteristic findings of a hair follicle occasionally dilated and containing keratin material surrounded by a moderately well-circumscribed thick mantle of fibrous tissue. The infundibular follicular epithelium extended out into this fibrous mantle forming epithelial strands or cords. There were no relapses after exeresis. Conclusion: Solitary fibrofolliculoma is a rare lesion, seldom affecting the eyelids. We reported 11 cases, and the third case reported thus far in the literature affecting the lids. Diagnosis may be easily missed due to the nonspecific symptoms and clinical appearance. Therefore, it is necessary to perform excisional biopsy and histological examination for the recognition of this lesion.

RESUMO Objetivo: o objetivo deste estudo foi relatar uma série de casos de fibrofoliculoma solitário, uma lesão raramente observada nas pálpebras. Demografia, bem como aspectos clínicos e histológicos da lesão foram avaliados. Métodos: Trata-se de uma série de casos retrospectivos, com um período de 18 anos. Todos os pacientes incluídos foram diagnosticados com fibrofoliculoma solitário confirmado por exame histológico. Foram coletados dados referentes à demografia, sinais e sintomas dos pacientes, evolução da doença, localização da lesão, diagnóstico clínico e histológico e desfecho. Resultados: Onze casos de fibrofoliculoma solitário foram diagnosticados no período do estudo. A média de idade dos pacientes de 51 ± 16,3 anos (variação: 27-78 anos). A maioria dos pacientes era do sexo feminino (7/11, 64%). Cinco dos pacientes (45%) eram assintomáticos; quatro (36%) relataram sangramento, um (9%) referiu coceira e um (9%) fricção da lesão. A lesão ocorreu em luma ampla variedade de locais; um deles sendo nas pálpebras. O diagnóstico de todas as lesões foi histológico com base nos achados característicos de um folículo piloso ocasionalmente dilatado e contendo material de queratina, cercado por um manto espesso de tecido fibroso moderadamente bem circunscrito. O epitélio infundibular folicular se estendeu até esse manto fibroso, formando cordões ou cordões epiteliais. Não houve recaídas após exérese. Conclusão: Fibrofoliculoma solitário é uma lesão rara, mais ainda quando afeta as pálpebras. Relatamos 11 casos, e o terceiro relatado até o momento na literatura que afeta as pálpebras. O diagnóstico pode ser facilmente esquecido devido a sintomas inespecíficos e aparência clínica. Portanto, é necessário realizar biópsia excisional e exame histológico para o reconhecimento dessa lesão.

A Stepwise Diagnostic Approach to Cystic Lung Diseases for Radiologists

Lung cysts are commonly seen on computed tomography (CT), and cystic lung diseases show a wide disease spectrum. Thus, correct diagnosis of cystic lung diseases is a challenge for radiologists. As the first diagnostic step, cysts should be distinguished from cavities, bullae, pneumatocele, emphysema, honeycombing, and cystic bronchiectasis. Second, cysts can be categorized as single/localized versus multiple/diffuse. Solitary/localized cysts include incidental cysts and congenital cystic diseases. Multiple/diffuse cysts can be further categorized according to the presence or absence of associated radiologic findings. Multiple/diffuse cysts without associated findings include lymphangioleiomyomatosis and Birt-Hogg-Dubé syndrome. Multiple/diffuse cysts may be associated with ground-glass opacity or small nodules. Multiple/diffuse cysts with nodules include Langerhans cell histiocytosis, cystic metastasis, and amyloidosis. Multiple/diffuse cysts with ground-glass opacity include pneumocystis pneumonia, desquamative interstitial pneumonia, and lymphocytic interstitial pneumonia. This stepwise radiologic diagnostic approach can be helpful in reaching a correct diagnosis for various cystic lung diseases.

Birt-Hogg-Dubé Syndrome Associated with a Renal Tumor / 대한내과학회지

Birt-Hogg-Dubé syndrome (BHD) is a rare autosomal dominant disorder characterized by the formation of hair follicle tumors, kidney tumors, and pulmonary cysts with recurrent spontaneous pneumothorax. A 44-year-old woman visited Wonkwang University Hospital with mild dyspnea. A chest X-ray on admission revealed pneumothorax in both lung fields. Chest computed tomography (CT) revealed both pneumothorax and multiple, irregularly shaped, variable-sized cysts in both lung fields. Upon physical examination, white dome-shaped papules were observed on the face. Histological examination of the skin lesion confirmed fibrofolliculoma, and genetic studies revealed a folliculin gene mutation. Abdominal CT revealed a 1-cm small solid renal mass at the lower pole of the right kidney. We surgically removed the renal tumor, and a histological diagnosis of oncocytoma was made. Here, we report a case of BHD that demonstrated all three clinical manifestations; this is the first case report of its kind in Korea.

Recurrent primary spontaneous pneumothorax in a large Chinese family: a clinical and genetic investigation / 中华医学杂志(英文版)

Background@#Primary spontaneous pneumothorax (PSP) is a common manifestation of Birt-Hogg-Dubé (BHD) syndrome, which is an autosomal dominant disorder caused by mutation of the folliculin (FLCN) gene. This study was established to investigate the mutation of the FLCN gene and the phenotype in a family with PSP.@*Methods@#We investigated the clinical and genetic characteristics of a large Chinese family with recurrent spontaneous pneumothorax. Genetic testing was performed by Sanger sequencing of the coding exons (4-14 exons) of the FLCN gene.@*Results@#Among ten affected members in a multi-generational PSP kindred, with a total of 18 episodes of spontaneous pneumothorax, the median age for the initial onset of pneumothorax was 42.5 years (interquartile range: 28.8-57.2 years). Chest computed tomography scan of the proband showed pulmonary cysts and pneumothorax. A novel nonsense mutation (c.1273C>T) in exon 11 of FLCN gene that leads to a pre-mature stop codon (p.Gln425*) was identified in the family. The genetic analysis confirmed the diagnosis of BHD syndrome in this family in the absence of skin lesions or renal tumors.@*Conclusions@#A novel nonsense mutation of FLCN gene was found in a large family with PSP in China. Our results expand the mutational spectrum of FLCN gene in patients with BHD syndrome.

Diagnosis and treatment of cystic lung disease

Cystic lung disease (CLD) is a group of lung disorders characterized by the presence of multiple cysts, defined as air-filled lucencies or low-attenuating areas, bordered by a thin wall (usually < 2 mm). The recognition of CLDs has increased with the widespread use of computed tomography. This article addresses the mechanisms of cyst formation and the diagnostic approaches to CLDs. A number of assessment methods that can be used to confirm CLDs are discussed, including high-resolution computed tomography, pathologic approaches, and genetic/serologic markers, together with treatment modalities, including new therapeutic drugs currently being evaluated. The CLDs covered by this review are lymphangioleiomyomatosis, pulmonary Langerhans cell histiocytosis, Birt-Hogg-Dube syndrome, lymphocytic interstitial pneumonia/follicular bronchiolitis, and amyloidosis.

Birt-Hogg-Dubé Syndrome Manifesting as Spontaneous Pneumothorax: A Novel Mutation of the Folliculin Gene

Birt-Hogg-Dubé syndrome (BHDS) is a rare disease with autosomal dominant inheritance that manifests through skin tumors, pulmonary cystic lesions, and renal tumors. A mutation of FLCN located on chromosome 17p11.2, which encodes a tumor-suppressor protein (folliculin), is responsible for the development of BHDS. We report the case of a patient presenting with spontaneous pneumothorax, in whom a familial genetic study revealed a novel nonsense mutation: p.(Arg379*) in FLCN.

Birt-Hogg-Dubé Syndrome Manifesting as Spontaneous Pneumothorax: A Novel Mutation of the Folliculin Gene

Birt-Hogg-Dubé syndrome (BHDS) is a rare disease with autosomal dominant inheritance that manifests through skin tumors, pulmonary cystic lesions, and renal tumors. A mutation of FLCN located on chromosome 17p11.2, which encodes a tumor-suppressor protein (folliculin), is responsible for the development of BHDS. We report the case of a patient presenting with spontaneous pneumothorax, in whom a familial genetic study revealed a novel nonsense mutation: p.(Arg379*) in FLCN.

Benign follicular tumors

Abstract: Benign follicular tumors comprise a large and heterogeneous group of neoplasms that share a common histogenesis and display morphological features resembling one or several portions of the normal hair follicle, or recapitulate part of its embryological development. Most cases present it as clinically nondescript single lesions and essentially of dermatological relevance. Occasionally, however, these lesions be multiple and represent a cutaneous marker of complex syndromes associated with an increased risk of visceral neoplasms. In this article, the authors present the microscopic structure of the normal hair follicle as a basis to understand the type and level of differentiation of the various follicular tumors. The main clinicopathological features and differential diagnosis of benign follicular tumors are then discussed, including dilated pore of Winer, pilar sheath acanthoma, trichoadenoma, trichilemmoma, infundibuloma, proliferating trichilemmal cyst/tumor, trichoblastoma and its variants, pilomatricoma, trichodiscoma/fibrofolliculoma, neurofollicular hamartoma and trichofolliculoma. In addition, the main syndromes presenting with multiple follicular tumors are also discussed, namely Cowden, Birt-Hogg-Dubé, Rombo and Bazex-Dupré-Christol syndromes, as well as multiple tumors of follicular infundibulum (infundibulomatosis) and multiple trichoepitheliomas. Although the diagnosis of follicular tumors relies on histological examination, we highlight the importance of their knowledge for the clinician, especially when in presence of patients with multiple lesions that may be the cutaneous marker of a cancer-prone syndrome. The dermatologist is therefore in a privileged position to recognize these lesions, which is extremely important to provide further propedeutic, appropriate referral and genetic counseling for these patients.

Birt-Hogg-Dube syndrome incidentally diagnosed during asthma management

Birt-Hogg-Dube (BHD) syndrome is an autosomal dominant hereditary disorder characterized by 3 clinical manifestations, including skin fibrofolliculomas, multiple pulmonary cysts with or without spontaneous pneumothorax, and spontaneous renal tumor. A 60-year-old Korean male who had suffered from bronchial asthma incidentally diagnosed with multiple pulmonary cysts by computed tomography during a regular follow-up. Genetic studies revealed folliculin gene mutation that was a confirmative finding of BHD syndrome. Although this case showed no cutaneous manifestations or renal abnormality, genetic studies of his family and regular follow-up are recommended.

Two Cases of Birt-Hogg-Dube Syndrome with Pulmonary Cysts / 대한내과학회지

Birt-Hogg-Dube (BHD) syndrome is a rare autosomal-dominant disease caused by germline folliculin (FLCN) mutations, characterized by fibrofolliculoma or trichodiscoma, renal tumors, and multiple lung cysts with or without spontaneous pneumothorax. Here, we report two cases of BHD syndrome that presented with bilateral pulmonary cysts. One patient was a 39-year-old woman who had a history of pneumothorax, multiple papules on her cheeks, and a family history of the same skin lesions and renal cell carcinoma in her father. BHD syndrome was confirmed by molecular tests that revealed a missense mutation in FLCN gene (exon 4, c.31T > C). The other patient was a 56-year-old man who showed FCLN gene polymorphism and typical radiopathological features of multiple cysts in the lung, but apparently no other manifestation.

Birt-Hogg-Dubé syndrome / Sindrome de Birt-Hogg-Dube

A 45-year-old woman with a history of renal carcinoma was observed for facial, cervical and truncal flesh-colored papules. Relatives had similar skin findings and a brother had repeated episodes of pneumothorax. The computerized tomography scan revealed multiple cysts on both lungs. A skin biopsy revealed a perifollicular fibroma. The clinical diagnosis of Birt-Hogg-Dubé syndrome (BHDS) was corroborated by identification of a novel frameshift c.573delGAinsT (p.G191fsX31) mutation in heterozygosity on exon 6 of the folliculin gene. The presence of multiple and typical benign hair follicle tumors highlights the role of the dermatologist in the diagnosis of this rare genodermatosis that is associated with an increased risk of renal cell cancer and pulmonary cysts, warranting personal and familial follow-up and counseling.

Uma mulher de 45 anos com história de carcinoma renal foi observada por pápulas cor da pele, faciais, cervicais e tronculares. Referia história familiar de achados cutâneos semelhantes e irmão com episódios repetidos de pneumotórax. Identificaram-se múltiplos quistos pulmonares por tomografia computorizada. Uma biópsia cutânea revelou fibroma perifolicular. O diagnóstico clínico de síndrome de Birt-Hogg-Dubé (BHDS) foi contudo corroborado pela identificação de uma nova mutação frameshift c.573delGAinsT (p.G191fsX31) em heterozigotia no exão 6 do gene da foliculina. A presença de múltiplos e típicos tumores benignos do folículo piloso, realça o papel do dermatologista no diagnóstico desta rara genodermatose, que está associada a um risco aumentado de tumores de células renais e cistos pulmonares, exigindo seguimento e aconselhamento pessoal e familiar.

Multiple Cystic Lung Disease / 결핵및호흡기질환

A lung cyst is an air-filled lucent structure surrounded by a thin wall. The presence of multiple intrapulmonary cysts is defined as cystic lung disease. Although cystic lung disease is rare, incidental detection has increased significantly in recent years by screening using computed tomography. There are many conditions that can mimic lung cysts and cause cystic lung disease. Clinical, radiographic, and histologic findings are all necessary for a proper diagnosis, and multidisciplinary approaches are frequently required. The aim of this report is to review the causes and characteristics of cystic lung disease to better understand and improve treatment.

Genetic Study in a Case of Birt-Hogg-Dube Syndrome

Birt-Hogg-Dube 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.

Birt-Hogg-Dube 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-Dube 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.

A Case of Birt-Hogg-Dube Syndrome

Birt-Hogg-Dube 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.