National survey of bladder endometriosis cases in Japan.

AIM: We aimed to describe the clinical presentation, operative or medical management, and postoperative recurrence of bladder endometriosis (BE). METHODS: We conducted a national survey to investigate BE cases from 2006 to 2016 in Japan. Histologically diagnosed cases were extracted and then investigated for the following factors: age at diagnosis, body mass index, symptoms, imaging modalities, surgical therapy, hormonal therapy, follow-up period, and postoperative recurrence. RESULTS: Eighty-nine patients with pathologically benign BE were identified. Eighty patients underwent surgery, whereas nine did not. Moreover, 34 and 44 patients underwent transurethral resection (TUR) and partial cystectomy (PC), respectively. Cumulative recurrence rates were significantly higher with TUR than with PC (p < 0.05). The recurrence rate tended to be higher after laparoscopic PC (n = 24) than after open PC (n = 20), but the difference was not statistically significant (p = 0.0879). Of the nine nonsurgical patients, eight received hormonal therapy and one did not. Efficacy rates of dienogest, GnRH agonist, and OC were 85.7%, 66.7%, and 66.7%, respectively. Of five patients with BE extending to the ureter or ureteral orifices, two underwent PC and ureteroneocystostomy and one underwent total nephroureterectomy due to renal function loss. CONCLUSION: To our knowledge, this is the first study to compare the postoperative recurrence of BE after TUR and PC. We found that cumulative recurrence rate is significantly lower after PC than after TUR. BE extending to the ureter or ureteral orifices is a very challenging condition. Further studies are required for the optimal management of BE.

A National Survey of Umbilical Endometriosis in Japan.

STUDY OBJECTIVE: To identify the clinical presentation, diagnostic evaluation, operative or medical management, and postoperative recurrence of umbilical endometriosis. DESIGN: A retrospective national survey. SETTING: Obstetrics and Gynecology and Plastic Surgery Departments at a teaching hospital in Japan. PATIENTS: Patients with umbilical endometriosis or malignant transformation. INTERVENTIONS: A national survey was conducted to identify and evaluate cases of umbilical endometriosis or malignant transformation documented between 2006 and 2016. MEASUREMENTS AND MAIN RESULTS: The following were evaluated for each patient: age at diagnosis, body mass index, medical history, presence of extragenital endometriosis, surgical history, symptoms, imaging modalities, surgical therapy, hormonal therapy, follow-up period, postoperative recurrence, and time to recurrence. Ninety-six patients were identified with pathologically diagnosed benign umbilical endometriosis. The patients frequently had swelling (86.5%), pain (81.3%), or bleeding (44.8%) in the umbilicus. Sensitivity was 87.1% for physical examination, 76.5% for transabdominal ultrasonography, 75.6% for computed tomography, and 81.8% for magnetic resonance imaging. The cumulative recurrence rate was 1.34% at 6 months, 6.35% at 12 months, and 6.35% at 60 months after surgery. Importantly, there was no recurrence after wide resection including of the peritoneum (0 of 37 cases). The efficacy of dienogest (an oral progestin), gonadotropin-releasing hormone agonists, and oral contraceptives was 91.7%, 81.8%, and 57.1%, respectively. Finally, 2 cases of malignant transformation were identified. CONCLUSION: There was a low recurrence rate following surgery, and hormonal treatment is an option, although the current findings suggest surgical therapy as the first choice of treatment for umbilical endometriosis.

Clinical practice guidelines for the treatment of extragenital endometriosis in Japan, 2018.

The aim of this publication is to disseminate the clinical practice guidelines for the treatment of intestinal, bladder/ureteral, thoracic and umbilical endometriosis, already published in Japanese, to non-Japanese speakers. For developing the original Japanese guidelines, the clinical practice guideline committee was formed by the research team for extragenital endometriosis, which is part of the research program of intractable disease of the Japanese Ministry of Health, Labor and Welfare. The clinical practice guideline committee formulated eight clinical questions for the treatment of extragenital endometriosis, which were intestinal, bladder/ureteral, thoracic and umbilical endometriosis. The committee performed a systematic review of the literature to provide responses to clinical questions and developed clinical guidelines for extragenital endometriosis, according to the process proposed by the Medical Information Network Distribution Service. The recommendation level was determined using modified Delphi methods. The clinical practice guidelines were officially approved by the Japan Society of Obstetrics and Gynecology and the Japan Society of Endometriosis. This English version was translated from the Japanese version.

A novel dual-covering method in video-assisted thoracic surgery for pediatric primary spontaneous pneumothorax.

BACKGROUND: Primary spontaneous pneumothorax (PSP) generally occurs in young adults, whereas pediatric PSP is uncommon. It is difficult to source reliable data on pediatric PSP, the management of which is based on guidelines for adult PSP; however, the rate of recurrence after video-assisted thoracoscopic surgery (VATS) for pediatric PSP is reported to be higher. METHODS: We reviewed retrospectively a collective total of 66 surgical cases of a first pneumothorax episode in 46 children under 16 years of age, who were treated at our hospital between February, 2005 and November, 2017. RESULTS: The surgical cases were divided into two groups, depending on how the treated lesions were covered. In the dual-covering (DC) group, the PSP was covered by oxidized regenerated cellulose and polyglycolic acid (8 patients; 13 cases) and in the single-covering (SC) group, the PSP was covered by oxidized regenerated cellulose (38 patients; 53 cases). There was no incidence of recurrence after surgery in the DC group, but 17 cases (32.1%) of recurrence after surgery in the SC group. This difference was significant. CONCLUSION: The DC method prevented the recurrence of PSP more effectively than the SC method after VATS in pediatric patients. Long-term follow-up after VATS for pediatric PSP is also important because of the risk of delayed recurrence.

Novel clinical scoring system to identify patients with pneumothorax with suspicion for Birt-Hogg-Dubé syndrome.

BACKGROUND AND OBJECTIVE: Birt-Hogg-Dubé syndrome (BHDS) is a rare hereditary disease that presents with multiple lung cysts and pneumothorax (PTX). Although some reports propose that findings from chest computed tomography enable one to distinguish BHDS from primary spontaneous pneumothorax (PSP), it is still unclear whether clinical features are useful for identifying patients with suspicion of BHDS from those with PTX. METHODS: We retrospectively reviewed the medical records of patients with PTX who underwent video-assisted thoracoscopic surgery at Nissan Tamagawa Hospital from January 2012 to December 2015. RESULTS: We identified a total of 1141 patients with PTX, including 54 with BHDS and 517 with PSP. Among them, logistic regression analysis segregated five features that were significantly associated with BHDS: familial history of PTX, past history of bilateral PTX, age at the first episode of PTX (≥25 years old (y.o.)), body mass index (≥18.5) and gender (female). We assigned scores of 3, 3, 2, 2 and 1 to the five features, respectively, to establish a system with a calculated score from 0 to 11. The cut-off value of a calculated score ≥ 4 yielded the highest sensitivity of 93% and specificity of 86%. Receiver operating characteristic (ROC) analysis showed the area under the curve reflecting an accuracy of this diagnostic test as 0.953. CONCLUSION: BHDS has several clinical features distinct from PSP. Our scoring system consists of only five clinical variables that are easily evaluated and efficiently separate BHDS patients from those who have PTX without relying on an imaging study. Further prospective study is needed to confirm our findings.

Oxidized regenerated cellulose induces pleural thickening in patients with pneumothorax: possible involvement of the mesothelial-mesenchymal transition.

PURPOSE: The pleural covering technique, i.e., wrapping a part of or the entire surface of the lung with oxidized regenerative cellulose (ORC), reinforces visceral pleura through pleural thickening for patients with pneumothorax and cystic lung diseases. However, it remains undetermined how ORC induces pleural thickening. METHODS: A histopathological examination was performed for lung specimens from patients who had recurrent pneumothoraces after pleural covering and re-operation (n = 5). To evaluate the influence of ORC on the pleura in vitro, we used MeT-5A cells (a human pleural mesothelial cell line). RESULTS: Pleural thickening was confirmed in all lung specimens examined. Three months after covering, the thickened pleura showed inflammatory cell infiltration, proliferation of myofibroblasts, and expression of fibronectin and TGF-ß. However, after 1 year, those findings virtually disappeared, and the thickened pleura was composed mainly of abundant collagen. When MeT-5A cells were cultured in ORC-immersed medium, their morphology changed from a cobblestone to spindle-shaped appearance. The expression of E-cadherin decreased, whereas that of N-cadherin, α-smooth muscle actin, and fibronectin increased, suggesting mesothelial-mesenchymal transition (Meso-MT). CONCLUSIONS: Our results suggest that Meso-MT may be involved as a mechanism of pleural thickening induced by pleural covering with ORC.

Isolation of individual cellular components from lung tissues of patients with lymphangioleiomyomatosis.

Lymphangioleiomyomatosis (LAM) is a rare neoplastic disease entailing cystic destruction of the lungs and progressive respiratory failure. LAM lungs are histologically characterized by the proliferation of smooth muscle-like cells (LAM cells) and an abundance of lymphatic vessels. To elucidate the pathophysiological processes of LAM, cell-type-specific analyses are required. However, no method exists for isolating the individual types of cells in LAM lesions. Therefore, we established a fluorescence-activated cell sorting (FACS)-based method for the direct isolation of LAM cells and other various cellular components from LAM-affected lung tissue. We obtained LAM-affected lung tissue from resections or transplant recipients and prepared single-cell suspensions. FACS, immunohistochemical, and molecular analysis were used cooperatively to isolate HMB45-positive LAM cells with tuberous sclerosis complex (TSC) 2 loss of heterozygosity (LOH). Using a combination of antibodies against an epithelial cell adhesion molecule (EpCAM) and podoplanin, we fractionated CD45-negative lung cells into three groups: lymphatic endothelial cells (LEC) (EpCAM(-)/podoplanin(hi) subset), alveolar type II cells (EpCAM(hi)/podoplanin(-) subset), and mesenchymal cells (EpCAM(-)/podoplanin(-/low) subset). During subsequent analysis of HMB45 expression, as a LAM-specific marker, we clearly identified LAM cells in the mesenchymal cell population. We then discovered that CD90(+)/CD34(-) cells in the mesenchymal cell population are not only positive for HBM45 but also had TSC2 LOH. These isolated cells were viable and subsequently amenable to cell culture. This method enables us to isolate LAM cells and other cellular components, including LAM-associated LEC, from LAM-affected lung tissues, providing new research opportunities in this field.

Clinical characteristics of catamenial and non-catamenial thoracic endometriosis-related pneumothorax.

BACKGROUND AND OBJECTIVE: A major pathogenic factor for catamenial pneumothorax is thoracic endometriosis. However, thoracic endometriosis-related pneumothorax (TERP) can develop as either catamenial or non-catamenial pneumothorax (CP). Therefore, the aim of this study was to elucidate the clinical differences between catamenial and non-catamenial TERP. METHODS: The clinical and pathological data in female patients who underwent video-assisted thoracoscopic surgery at the Pneumothorax Research Center during an 8-year period were retrospectively reviewed. This study included 150 female patients with surgico-pathologically confirmed TERP. The subjects were divided into two groups, those having all of the pneumothorax episodes in the catamenial period (CP group) and those who did not (non-CP group). We compared the clinical characteristics and surgico-pathological findings between these two groups. RESULTS: Of the 150 TERP patients, 55 (36.7%) were classified in the CP group, and 95 (63.3%) in the non-CP group. In regard to the locations of endometriosis, all TERP patients had diaphragmatic endometriosis, while pleural implantation was recognized in 34 of the 55 (61.8%) patients in the CP group and 42 of the 95 (44.2%) patients in the non-CP group (P < 0.05). CONCLUSIONS: A significant difference in the proportion of patients with pleural endometriosis was observed between catamenial and non-catamenial TERP. The ectopic sites of the endometriosis may be responsible for the timing of the pneumothorax episodes.

[Emergency Surgery and Treatments for Pneumothorax].

The primary care in terms of emergency for pneumothorax is chest drainage in almost cases. The following cases of pneumothorax and the complications need something of surgery and treatments. Pneumothorax with subcutaneous emphysema often needs small skin incisions around the drainage tube. Tension pneumothorax often needs urgent chest drainage. Pneumothorax with intractable air leakage often needs interventional treatments like endobroncheal occlusion (EBO) or thoracographic fibrin glue sealing method (TGF) as well as urgent thoracoscopic surgery. Pneumothorax with acute empyema also often needs urgent thoracoscopic surgery within 2 weeks if chest drainage or drug therapy are unsuccessful. It will probably become chronic empyema of thorax after then. Pneumothorax with bleeding needs urgent thoracoscopic surgery in case of continuous bleeding over 200 ml/2 hours. In any cases of emergency for pneumothorax, respiratory physicians should collaborate with respiratory surgeons at the 1st stage because it is important to timely judge conversion of surgical treatments from medical treatments.

Characterization of pulmonary cysts in Birt-Hogg-Dubé syndrome: histopathological and morphometric analysis of 229 pulmonary cysts from 50 unrelated patients.

AIMS: To characterize the pathological features of pulmonary cysts, and to elucidate the possible mechanism of cyst formation in the lungs of patients with Birt-Hogg-Dubé syndrome (BHDS), a tumour suppressor gene syndrome, using histological and morphometric analyses. METHODS AND RESULTS: We evaluated 229 lung cysts from 50 patients with BHDS and 117 from 34 patients with primary spontaneous pneumothorax (PSP) for their number, size, location and absence or presence of inflammation. The BHDS cysts abutted on interlobular septa (88.2%) and had intracystic septa (13.6%) or protruding venules (39.5%) without cell proliferation or inflammation. The frequencies of these histological characteristics differed significantly from those seen in the lungs of patients with PSP (P < 0.05). Although the intrapulmonary BHDS cysts were smaller than the subpleural BHDS cysts (P < 0.001), there was no difference in size between them when there was no inflammation. The number of cysts diminished logarithmically and the proportion of cysts with inflammation increased as their individual sizes became greater (P < 0.05). CONCLUSIONS: These results imply that the BHDS cysts are likely to develop in the periacinar region, an anatomically weak site in a primary lobule, where alveoli attach to connective tissue septa. We hypothesize that the BHDS cysts possibly expand in size as the alveolar walls disappear at the alveolar-septal junction, and grow even larger when several cysts fuse.

Thoracic endometriosis-related pneumothorax distinguished from primary spontaneous pneumothorax in females.

PURPOSE: Thoracic endometriosis-related pneumothorax (TERP) is a secondary condition specific for females, but in a clinical setting, TERP often is difficult to distinguish from primary spontaneous pneumothorax (PSP) based on a relationship between the dates of pneumothorax and menstruation. The purpose of this study was to clarify the clinical features of TERP compared with PSP. METHODS: We retrospectively reviewed the clinical and histopathological files of female patients with pneumothorax who underwent video-assisted thoracoscopic surgery in the Pneumothorax Research Center during the 6-year period from January 2005 to December 2010. We analyzed the clinical differences between TERP and PSP. RESULTS: The study included a total of 393 female patients with spontaneous pneumothorax, of whom 92 (23.4 %) were diagnosed as having TERP and 33.6 % (132/393) as having PSP. We identified four factors (right-sided pneumothorax, history of pelvic endometriosis, age ≥31 years, and no smoking history) that were statistically significant for predicting TERP and assigned 6, 5, 4, and 3 points, respectively, to establish a scoring system with a calculated score from 0 to 18. The cutoff values of a calculated score ≥12 yielded the highest positive predictive value (86 %; 95 % confidence interval (CI) 81.5-90.5 %) for TERP and negative predictive value (95.2 %; 95 % CI 92.3-98 %) for PSP. CONCLUSIONS: TERP has several distinct clinical features from PSP. Our scoring system consists of only four clinical variables that are easily obtainable and enables us to suspect TERP in female patients with pneumothorax.

Risk for re-expansion pulmonary edema following spontaneous pneumothorax.

PURPOSE: Re-expansion pulmonary edema is an uncommon condition that occurs when a collapsed lung is expanded. The aim of the present study was to investigate the incidence and risk factors associated with re-expansion pulmonary edema which may occur as a complication when carrying out treatment for spontaneous pneumothorax. METHODS: A total of 462 patients with spontaneous pneumothorax treated with chest tube drainage in inpatient settings at the Nissan Tamagawa Hospital during the 6-year period between January 2007 and December 2012 were retrospectively evaluated. The data were analyzed to identify any clinical differences between the patients with and without re-expansion pulmonary edema. RESULTS: Re-expansion pulmonary edema occurred on 30 (6.5 %) of the 462 patients. The duration of lung collapse in the patients with re-expansion pulmonary edema was longer than that observed in the patients without re-expansion pulmonary edema. (7.7 ± 9.1 and 2.4 ± 4.6 days). This difference was statistically significant (P < 0.0001). The extent of lung collapse in the patients with re-expansion pulmonary edema was more severe than that observed in the patients without re-expansion pulmonary edema. This difference was also statistically significant (P = 0.004). CONCLUSIONS: The results suggest that treating spontaneous pneumothorax using chest tube drainage requires careful consideration in view of the relatively high incidence of re-expansion pulmonary edema, especially in cases associated with long periods of lung collapse or large spontaneous pneumothoraxes.

Immunohistochemical analysis of thoracic endometriosis.

Thoracic endometriosis is a rare disease responsible for catamenial pneumothorax. The immunohistochemical features of thoracic endometriosis are not well understood. An immunohistochemical examination of 84 diaphragmatic specimens of catamenial pneumothorax using antibodies against estrogen receptor (ER), progesterone receptor (PgR), CD10 and smooth muscle actin (SMA) was conducted. The endometrial tissue was small, and focally located around the chasm of the tendon on the side of the thoracic cavity. Endometrial stroma were detected in 84/84 (100%) of the specimens, endometrial glands were detected in 21/84 (25%) and smooth muscle was detected in 1/84 (1.2%). The endometrial stroma exhibited positive staining for ER in 74/84 (88.1%) of the specimens, PgR in 84/84 (100%), CD10 in 74/84 (88.1%) and SMA in 46/84 (54.8%). Because thoracic endometriosis is small in size, and only 25% of the resected tissue specimens were accompanied with the endometrial gland, an immunohistochemical analysis can be useful for their detection. The fact that over half of the thoracic endometrial stroma showed positive staining for SMA, and the existence of thoracic endometriosis accompanied by smooth muscle, indicated that some part of the thoracic endometriosis may have the ability to differentiate into smooth muscle, although further studies are needed to confirm this hypothesis.

Postoperative hormonal therapies reduce the recurrence of thoracic endometriosis-related pneumothorax.

OBJECTIVES: Thoracic endometriosis-related pneumothorax (TERP) frequently recurs even after surgery. Meanwhile, postoperative hormonal therapies (HTx) are believed to be effective for pelvic endometriosis. Therefore, we evaluated the relationship between postoperative TERP recurrence and postoperative HTx in a retrospective observational study. METHODS: We retrospectively reviewed the data of patients with TERP who underwent the first video-assisted thoracoscopic surgery between January 2011 and February 2022. RESULTS: Of the 248 patients eligible for this study, 67 (27.0%) experienced postoperative TERP recurrence. Postoperative HTx were administered to 70 patients (28.2%). Dienogest was the most frequently administered drug, given to 56.7% of patients. Following univariable analysis, postoperative hormonal therapies was closely related to reduce postoperative recurrence (P = 0.003). Likewise, the multivariable analysis revealed postoperative hormonal therapies were significantly associated with the risk reduction of recurrence (hazard ratio 0.28, P < 0.001). CONCLUSIONS: Postoperative HTx reduced TERP recurrence. We hypothesize that HTx may control residual endometrial tissues to avoid TERP if pleural endometrial tissues are resected as much as possible.

Clinical and genetic features of 334 Asian patients with Birt-Hogg-Dubé syndrome (BHDS) who presented with pulmonary cysts with or without a history of pneumothorax, with special reference to BHDS-associated pneumothorax.

BACKGROUND: The clinical pulmonary manifestations and genetic features of Birt-Hogg-Dubé syndrome (BHDS) in Asian patients remained unclear. We aimed to clarify the clinical features of BHDS-associated pneumothorax (PTX) and retrospectively investigate potential contributing factors in the largest Asian cohort to date. METHODS: We reviewed the clinical and genetic data collected in 2006-2017, from the BHDS patients who were Asian and presented with pulmonary cysts with or without a history of PTX. RESULTS: Data from 334 (41.3% males; 58.7% females) patients from 297 unrelated families were reviewed. Among them, 314 (94.0%) patients developed PTX. The median age at the first occurrence of PTX was 32 years, which was significantly lower in males (P = 0.003) and patients without notable skin manifestations (P < 0.001). Seventy-six (24.2%) patients experienced their first PTX episode before the age of 25 years. PTX simultaneously occurred in the bilateral lungs of 37 (11.8%) patients. Among 149 patients who had their first PTX episode at least 10 years before BHDS diagnosis, PTX occurred more frequently in males (P = 0.030) and light smokers than in nonsmokers (P = 0.014). The occurrence of PTX peaked in the early 30s and gradually decreased with age but remained high in females (P = 0.001). We identified 70 unique FLCN germline variants, including duplications (46.4%), substitutions (7.1%), insertions/deletions (30.0%), and variants affecting splicing (12.5%). Approximately 80% of Asian patients suspected of having BHDS could be genetically diagnosed by examining FLCN exons 7, 9, 11, 12, and 13. No apparent genotype-phenotype correlation regarding pulmonary manifestations was identified. CONCLUSIONS: Our findings indicate that sex, smoking history, and skin manifestations at BHDS diagnosis significantly influence the clinical features of BHDS-associated PTX. These findings may contribute to the appropriate management and treatment of BHDS-associated PTX.

Clinicopathological Impacts of Expression of Neuronal Markers in Lymphangioleiomyomatosis.

Lymphangioleiomyomatosis (LAM) is a tuberous sclerosis complex (TSC)-associated tumor, characterized by the expression of neural crest lineages including neuronal markers. Neural crest cells can differentiate into multiple cell types that contribute to tissues associated with TSC-related tumors, and TSC-related tumors could be specifically associated with distinct neural crest subtypes. This study aimed to clarify the clinicopathological effects of expression of neuronal markers in LAM. Lung tissues from 40 patients with LAM (of whom 13, 1, and 26 had undergone lung transplantation, lobectomy, and partial lung resection, respectively) were immunohistochemically analyzed. All patients were women, and their median age was 36 years (range: 24-62 y). All patients who underwent lung transplantation or lobectomy were classified as LAM histologic score (LHS)-3, whereas those who underwent partial lung resection were classified as LHS-1. LAM cells expressed peripherin (65%), and neuron-specific ßIII-tubulin (43%). A comparison of the early (LHS-1) and advanced (LHS-3) stages of LAM revealed that neuron-specific ßIII-tubulin was significantly expressed in the early stage of LAM ( P = 0.0009). Neuron-specific ßIII-tubulin-positive LAM was associated with younger age ( P < 0.0001), the coexistence of renal angiomyolipoma ( P = 0.027), and the absence of retroperitoneal LAM ( P = 0.045). Furthermore, based on the expression levels of immunohistochemical markers in LAM, 2 distinct clusters with different expression levels of neuronal markers were observed. Approximately 40% to 60% of patients with LAM expressed neuron-specific ßIII-tubulin and peripherin. Neuronal expression may be associated with disease severity.

Current opinion and comparison of surgical procedures for the treatment of primary spontaneous pneumothorax.

INTRODUCTION: Although three-port video-assisted thoracoscopic surgery (VATS) is the standard radical treatment for primary spontaneous pneumothorax (PSP), several issues need to be addressed as the postoperative recurrence rate remains relatively high. Although bullectomy is effective in preventing the postoperative recurrence of PSP, recurrent pneumothorax often occurs, requiring additional methods such as pleural covering with absorbable mesh sheets, surgical chemical pleurodesis, pleural abrasion, or pleurectomy. In addition, minimally invasive approaches that exceed three-port VATS are required according to the social demand. These approaches, such as uniportal VATS, reduced port surgery, and needlescopic surgery, have cosmetic merits, lower postoperative pain, and similar surgical results as three-port VATS. AREAS COVERED: We focused on conventional and novel treatments for PSP in this article. EXPERT OPINION: Effective methods that prevent postoperative recurrence and minimally invasive approaches will become popular in the near future.

Dynamics of thoracic endometriosis in the pleural cavity.

BACKGROUND: Thoracic endometriosis-related pneumothorax is a secondary spontaneous pneumothorax caused by thoracic endometriosis. Diaphragmatic endometriosis is well-studied, but visceral and/or parietal pleural lesions are not. Although surgery is an effective treatment, postoperative recurrence rates are unsatisfactory probably due to inadequate understanding of underlying pathophysiology. We aimed to clarify the clinicopathological features of thoracic endometriosis. METHODS: In total, 160 patients who underwent thoracoscopic surgery from a single institution with histopathologically proven thoracic endometriosis from January 2015 to December 2019 were included. Clinicopathological characteristics and surgical outcomes were assessed retrospectively. RESULTS: The cohort median age was 41 (range 22-53) years. Pneumothorax was right-sided in 159 (99.4%) and left-sided in only 1 (0.6%) case. Visceral and parietal pleural lesions were diagnosed in 79 (49.4%) and 71 (44.4%) patients, respectively. In total, 104 visceral pleural lesions and 101 parietal pleural lesions were detected. The S4 region and the dorsal 6th intercostal space contained the largest number of visceral pleural (66 lesions) and parietal pleural lesions (25 lesions), respectively. Histopathological evaluation revealed endometriotic tissues, existing in the outer external elastic layer in all lesions, were localized or invaded deeply. The median follow-up period was 370 (range, 6-1824) days. The Kaplan-Meier method revealed that the 1- and 2-year postoperative recurrence rates were 13.8% and 19.3%, respectively. CONCLUSIONS: Visceral pleural endometriotic lesions may be disseminated from the visceral pleural surface and infiltrate into the pleura. Intraoperatively, careful observation of the specific sites, such as the visceral pleura of S4 and the parietal pleura of 6th intercostal space, is important to reduce postoperative recurrence.

Seventh BHD international symposium: recent scientific and clinical advancement.

The 7th Birt-Hogg-Dubé (BHD) International Symposium convened virtually in October 2021. The meeting attracted more than 200 participants internationally and highlighted recent findings in a variety of areas, including genetic insight and molecular understanding of BHD syndrome, structure and function of the tumor suppressor Folliculin (FLCN), therapeutic and clinical advances as well as patients' experiences living with this malady.

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.