肺淋巴管平滑肌瘤病的临床分析

目的探讨肺淋巴管平滑肌瘤病(LAM)的临床特征,治疗和预后。方法回顾性分析1例LAM病人并复习文献78例。结果全部79例患者中,女性占多数74例(93.7%)。发病年龄:69例(87.3%)为育龄期妇女,均经肺组织活检病理确诊。临床表现为呼吸困难(75例),咯血(40例),气胸(38例),乳糜胸(24例),行胸部高分辩CT(HRCT)扫描63例,均显示两肺弥漫性薄壁囊状阴影;行肺功能检查45例,阻塞性通气功能障碍32例,混合性通气功能障碍9例,行血气分析43例,其中低氧血症41例,型呼吸衰竭2例;给予安宫黄体酮及其他药物治疗32例,其中死亡或病情加重19例,其中11例从确诊到死亡时间为0.5-3.5年。结论LAM以呼吸困难,咯血、气胸和乳糜胸为主要临床特征,安宫黄体酮疗效不理想。     

淋巴管肌瘤病3例并文献复习

目的探讨淋巴管肌瘤病(LAM)的临床特征和诊断,提高对LAM的认识和诊疗水平。方法回顾性分析3例LAM患者的临床资料,并复习相关文献。结果本组中女2例(43岁和36岁)、男1例(31岁),均出现无明显诱因的呼吸困难、咳嗽,并不断加重。其中病例1肺功能检查存在混合型通气功能障碍,肺弥散功能障碍;胸部高分辨CT(HRCT)示两肺散在囊状透光影,具有特征性表现。病例2有咯血症状,肺组织活检术后引流出胸腔乳糜液。3例术后病理组织检查确诊,病例1免疫组化染色见淋巴管平滑肌呈SM-action、Desmin阳性。结论LAM主要发生于育龄期妇女,无诱因的呼吸困难是最常见的临床表现,肺功能多表现为阻塞性通气功能障碍和弥散功能障碍;特征性的胸部HRCT检查有较高的诊断价值,病理活检和免疫组化检查可确诊。     

肺淋巴管平滑肌瘤病

目的　提高对罕见病肺淋巴管平滑肌瘤病 (PL AM)的认识。方法　对我院诊治的患者进行分析 ,并结合文献复习。结果　 PL AM是一种罕见的弥漫性肺部疾病 ,临床反复发作自发性气胸或 /和乳糜胸、活动后呼吸困难和痰血等。肺功能呈阻塞性或混合性通气功能障碍 ,低氧血症。胸部 X线表现为两肺弥漫分布网格状阴影 ,高分辨 CT(HRCT)示弥漫分布囊状改变。病理学检查示 :肺组织淋巴管增生和扩张 ,管外平滑肌明显增生。结论　育龄期妇女如反复发生气胸及出现原因不明的呼吸困难、咯血或乳糜胸 ,应疑诊 PL AM,及时行 HRCT及肺功能检查 ,必要时肺活检 ,以明确病理诊断。     

肺淋巴管平滑肌瘤病二例―附文献分析

目的提高对肺淋巴管平滑肌瘤病(PLAM)的认识并引起对该病的重视.方法对2例PLAM患者的临床资料进行分析,并结合文献进行复习.结果PLAM是一种持续发展的弥漫性肺间质疾病.临床表现为反复发作的自发性气胸、活动后呼吸困难、咯血和乳糜胸等.肺功能呈阻塞性肺通气功能障碍和弥散功能障碍,动脉血气分析显示低氧血症.胸部X线表现两肺弥漫性网格状,晚期呈蜂窝样变化.高分辨CT(HRCT)两肺广泛弥漫性分布的薄壁小囊状病变.病理学特点为肺淋巴管、小气道、小血管的管壁及其周围的平滑肌细胞弥漫性异常增生.免疫组化HMB45阳性.结论对育龄期妇女发生渐进性呼吸困难不能缓解,类似肺气肿的临床表现及X线胸片阴影,并出现反复气胸或乳糜胸水时即应考虑为PLAM可能,最好能以肺组织活检明确诊断.该病预后差,目前无有效的预防和治疗方法.     

肺淋巴管平滑肌瘤病九例临床和病理分析

目的 探讨肺淋巴管平滑肌瘤病(pulmonary lymphangionleiomyomatosis,PLAM)的临床和病理特征,提高临床诊治水平.方法 对广州呼吸疾病研究所确诊的9例PLAM患者的临床特点、影像学表现、肺功能及病理学检查进行分析并结合文献复习.结果 9例PLAM患者均为育龄期妇女(20～50岁),临床症状表现为呼吸困难(8/9)、咳嗽(6/9)、咯痰(2/9)、咯血(2/9)、胸痛(3/9)、自发性气胸(6/9)、乳糜胸(3/9)、乳糜性腹腔积液(2/9).胸部X线检查4例表现为双肺弥漫性网状结节影,2例表现为液气胸,2例表现为胸腔积液,1例表现为多发肺小囊状透光区及肺大疱,1例无异常.高分辨率CT具有特征性变化,9例双肺均可见多发小囊状影,直径2～20 mm,壁较薄.2例腹部CT于腹主动脉前可见多个肿大的淋巴结.6例患者进行了肺功能检查,3例通气功能正常,1例呈中度阻塞性通气功能障碍,1例呈重度混合性通气功能障碍,1例呈极重度混合性通气功能障碍,其中1例支气管舒张试验阳性.4例肺弥散功能下降.4例(4/9)经纤维支气管镜肺活检,5例(5/9)经胸腔镜活检,全部经病理确诊.病理学检查显示不同成熟度平滑肌细胞在细支气管壁、肺泡壁、淋巴管壁和血管壁周围增生,肺实质呈囊性变.结论 PLAM表现不典型,易被漏诊、误诊,应提高对本病的认识.     

肺淋巴管平滑肌瘤病二例一附文献分析

目的 提高对肺淋巴管平滑肌瘤病(PLAM)的认识并引起对该病的重视。方法 对2例PLAM患者的临床资料进行分析，并结合文献进行复习。结果 PLAM是一种持续发展的弥漫性肺间质疾病。临床表现为反复发作的自发性气胸、活动后呼吸困难、咯血和乳糜胸等。肺功能呈阻塞性肺通气功能障碍和弥散功能障碍，动脉血气分析显示低氧血症。胸部x线表现两肺弥漫性网格状，晚期呈蜂窝样变化。高分辨CT(HRCT)两肺广泛弥漫性分布的薄壁小囊状病变。病理学特点为肺淋巴管、小气道、小血管的管壁及其周围的平滑肌细胞弥漫性异常增生。免疫组化HMB45阳性。结论 对育龄期妇女发生渐进性呼吸困难不能缓解，类似肺气肿的临床表现及x线胸片阴影，并出现反复气胸或乳糜胸水时即应考虑为PLAM可能，最好能以肺组织活检明确诊断。该病预后差，目前无有效的预防和治疗方法。     

肺淋巴管肌瘤病的胸部影像学表现

目的探讨肺淋巴管肌瘤病（PLAM）的影像学表现。方法报告3例PLAM病例,结合文献资料对该病病因、临床特点及影像学表现进行讨论。结果 3例患者均为育龄期女性,首发症状均为活动后呼吸困难,其中1例合并气胸,1例合并气胸及乳糜胸,1例合并肺外淋巴管肌瘤。结合文献资料,本病常发于育龄期女性,临床表现依次为呼吸困难、咯血、气胸、乳糜胸等。本病X线片常呈非特异改变,CT较具特异性,主要表现为多发均匀分布囊状影,伴有间隔线,呈网格状改变,同时出现液气胸和淋巴结肿大,肺外也可有多发相关改变。肺功能测定常伴有阻塞性通气功能障碍。结论 CT检查对PLAM具有诊断价值。对育龄期妇女发生的渐进性呼吸困难、咯血、自发性气胸应及时进行胸部CT检查,并应常规进行腹部和盆腔影像学检查以了解患者是否合并肺外淋巴管平滑肌瘤。     

肺淋巴管肌瘤病11例报告并文献复习

目的 探讨肺淋巴管肌瘤病( PLAM)的临床和预后.方法 分析经治的11例PLAM病人的资料,并复习文献.结果 11例均为女性;年龄31 ～55岁,平均(44±9)岁;均经肺组织活检明确病理;主要临床表现为进行性呼吸困难10例(发生率91％),咳嗽6例(55％),咯血2例(18％),乳糜胸3例(27％),气胸3例(27％)等;11例患者均进行肺功能检测,均有弥散功能下降,9例行动脉血气分析,其中7例表现为低氧血症,4例合并呼吸衰竭;11例行胸部高分辨率CT (HRCT),均显示两肺弥漫性薄壁囊状阴影.结论 PLAM以呼吸困难,咳嗽,气胸和乳糜胸为主要临床表现;双肺弥漫性薄壁囊状阴影为影像学特征表现;肺组织活检是确诊的主要依据.     

安徽省淋巴管肌瘤病22例临床分析

目的总结安徽省淋巴管肌瘤病(LAM)患者临床特征,提高诊治水平。方法回顾分析2009年1月1日至2019年12月31日中科大附属第一医院LAM患者临床资料。结果本研究纳入22例女性LAM患者,平均诊断年龄(37±11)岁。近5年LAM诊断病例较前增加超三倍。所有患者胸部高分辨CT显示肺弥漫薄壁囊性病变。长期误诊20例(91%),平均误诊58月,误诊诊断为多发性肺大泡9例(41%)、肾癌6例(27%)和慢阻肺6例(23%)。最终病理确诊11例,临床诊断11例,其中VEGF-D≥800ng/L协助临床诊断5例(23%),TSC 2例,肾AML 2例,乳糜胸1例和肺外淋巴管肌瘤1例。临床表现以呼吸困难17例(77%)最常见,肺外症状10例(45%),并发气胸9例,复发率67%。西罗莫司有效率88%,气胸患者胸膜固定术后复发率25%。结论近5年LAM诊断数显著增加。育龄期女性出现呼吸困难、反复气胸,甚至肺外症状,应行胸部高分辨CT寻找特征性囊性病变,完善血清VEGF-D协助诊断LAM。西罗莫司能有效改善病情,并发气胸尽早行胸膜固定术,减少复发。     

西罗莫司治疗肺淋巴管肌瘤病伴巨大腹膜后淋巴管肌瘤1例及文献复习

<正>淋巴管肌瘤病 (lymphangioleiomyomatosis, LAM)是一种以育龄期女性出现肺部弥漫性囊性病变为主要特征的罕见疾病，常见临床表现为进行性呼吸困难、反复发作的气胸及乳糜胸，肺外表现以肾血管平滑肌脂肪瘤(angiomyolipoma, AML) 多见，目前国内报道LAM合并巨大腹膜后淋巴管平滑肌瘤罕见。本文总结1例西罗莫司成功治疗肺淋巴管肌瘤病伴巨大腹膜后淋巴管肌瘤，并结合文献进行复习，提高临床医生对该疾病的认识。     

Difficulties in the diagnosis of rare immunological diseases manifesting with cystic lung disease and spontaneous pneumothorax: Case reports

Pulmonary lymphangioleiomyomatosis (LAM) is a rare disease of an unknown cause affecting women of reproductive age and characterised by smooth muscle proliferation along lung lymphatic channels. Pneumothorax develops in up to 80% of patients with LAM and may be the presenting manifestation of the disease. Pneumothorax also precedes or complicates the clinical course of 25% of patients with Langerhans'-cell histiocytosis (LCH, histiocytosis X) pathologically characterised by involved tissue infiltration with large numbers of unusual Langerhans' cells, often organised as granulomas. A 41-year-old female patient was treated twice by simple tube drainage due to left pneumothorax in 1996. She was then diagnosed with chronic obstructive lung disease demonstrating with dyspnea, cough and wheeze. Abnormalities found in the high-resolution computed tomography (HRCT) scanning were characteristic of LAM with thin-walled parenchymal cysts distributed homogeneously in both lungs and with thickening of interlobular septa. A 38-year-old man was hospitalised due to chronic lung failure in the course of LCH characterised by small, poorly limited nodular lesions and thin-walled cysts revealed in HRCT scans. For two years of observation, he has suffered five episodes of right pneumothorax. When diagnosing pneumothorax in the middle-age patients, the possible cause of the disease is LAM or LCH. The use of HRCT scanning may enable good determination of the nature and distribution of parenchymal abnormalities found in the diseases.     

Lymphangiomyomatosis with a large retroperitoneal tumor]

A case of lymphangiomyomatosis (LAM) in a 35-year-old woman is reported. Because she was already severely dyspneic when she was admitted to our hospital, neither TBLB nor open lung biopsy was performed, and no accurate diagnosis was made. She died of respiratory failure three years after the development of exertional dyspnea, and autopsy revealed LAM. Pneumothorax, a well-known and frequent complication of LAM, did not occur until one month prior to her death. Although pneumothorax frequently complicates LAM, there are a few reports of cases in which pneumothorax did not occur during the course of the disease. We emphasize that LAM should be considered in the differential diagnosis of diffuse interstitial lung disease, even when the patient has no pneumothorax. The retroperitoneal tumor (15 x 10 x 10 cm), which was evident clinically, was later shown to be intra-abdominal involvement of LAM. Although only a few cases of LAM with a large retroperitoneal tumor have been reported, minor intra-abdominal involvement is relatively common. This case also suggested that the finding of a retroperitoneal tumor may be a diagnostic clue in LAM.     

Comprehensive evaluation of 35 patients with lymphangioleiomyomatosis

OBJECTIVES: To evaluate comprehensively the characteristics of lymphangioleiomyomatosis (LAM), with emphasis on the application of imaging and immunohistochemical methods. DESIGN: Prospective study. PATIENTS: Thirty-five female subjects with LAM. SETTING: Clinical Center, National Institutes of Health. INTERVENTIONS: BAL, pulmonary function test, ventilation/perfusion lung scans, CT of the chest and abdomen, ultrasonography of abdomen, and immunohistochemical study of lung biopsy specimens. RESULTS: Most patients had exertional dyspnea (83%) and pneumothorax (69%). BAL did not show diagnostic changes. The most common abnormalities on pulmonary function tests were decreased diffusing capacity of carbon monoxide (83%), hypoxemia (57%), and airway obstruction (51%). Bronchodilator response was found in 26% of patients. CT, which is almost pathognomonic, showed numerous thin-walled cysts throughout both lungs in all patients. Thirty-four patients (97%) had abnormal ventilation and/or perfusion lung scans. An unusual "speckling" pattern was observed on ventilation scans of 74% of patients. Common extrapulmonary features were retroperitoneal adenopathy (77%) and renal angiomyolipomas (60%). The percentage of abnormal smooth muscle cells (LAM cells), reactive with HMB45, varied from 17 to 67% in 10 lung biopsy specimens. CONCLUSIONS: Improved diagnostic methods have defined the abnormalities in patients with pulmonary LAM and increased the potential for early recognition and treatment of this disorder. Patients with LAM should be evaluated for bronchodilator responsiveness and may benefit from a trial of bronchodilators.     

Lymphangioleiomyomatosis: a clinical update

Lymphangioleiomyomatosis (LAM) is a rare, cystic lung disease that is associated with mutations in tuberous sclerosis genes, renal angiomyolipomas, lymphatic spread, and remarkable female gender restriction. The clinical course of LAM is characterized by progressive dyspnea on exertion, recurrent pneumothorax, and chylous fluid collections. Lung function declines at approximately twofold to threefold times the rate of healthy subjects, based on an annual drop in FEV1 of 75 to 120 mL in reported series. The diagnosis of pulmonary LAM can be made on high-resolution CT (HRCT) scan with reasonable certainty by expert radiologists, but generally requires a lung biopsy in cases in which tuberous sclerosis complex, angiomyolipomata, or chylous effusions are absent. The currently available treatment strategies are based on the antagonism of estrogen action, and are empiric and unproven. A trial of bronchodilators is warranted in patients with reversible airflow obstruction seen on pulmonary function testing. Pleurodesis should be performed with the initial pneumothorax, because the rate of recurrence is high. Angiomyolipomas that exceed 4 cm in size are more likely to bleed and should be evaluated for embolization. Air travel is well-tolerated by most patients with LAM. Lung transplantation is an important option for LAM patients, and can be safely performed by experienced surgeons despite prior unilateral or bilateral pleurodesis in most patients. Women with unexplained recurrent pneumothorax, tuberous sclerosis, or a diagnosis of primary spontaneous pneumothorax or emphysema in the setting of limited or absent tobacco use should undergo HRCT scan screening for LAM. Multicenter clinical trials based on several well-defined molecular targets are currently underway in the United States and Europe.     

When to suspect and how to diagnose pulmonary lymphangioleiomyomatosis

Abstract The objective of this study was to present clinical and radiological data of eight women with histologically proven lymphangioleiomyomatosis (LAM) diagnosed between 1984 and 1994, and to suggest a diagnostic strategy when LAM is suspected. A review of case reports, including results of biopsies, lung function and radiological procedures was undertaken. The mean age of the women at start of symptoms was 36 years, and the mean age at time of diagnosis 42 years. The most frequent presenting complaint was dyspnea, either in conjunction with pneumothorax (3), chylothorax (2) or on exertion (2). All patients had airflow limitation and markedly reduced gas transfer. Five patients had 16 episodes of pneumothorax. In seven patients multiple cysts were observed on the surface of the lung during thoracotomy while computerized tomography (CT) scans revealed numerous cysts evenly distributed throughout the lung parenchyma. The procedures that confirmed the diagnosis included transbronchial lung biopsy (4), open lung biopsy (2), thoracoscopy (1), thoracotomy (3) and autopsy (1). Three specimens had to be revised before the histological diagnosis was confirmed. It was concluded that the important clues to a diagnosis of LAM are recurrent episodes of pneumothoraces in fertile women, progressive air-flow limitation, markedly reduced gas transfer and characteristic findings on thoracic CT scans. A specific request to the pathologist to stain lung tissue specimens for smooth muscle cells is mandatory.     

肺郎格罕细胞组织细胞增多症7例临床分析

目的探讨肺郎格罕(Langerhans)细胞组织细胞增多症的临床表现,以提高对本病的认识。方法回顾性分析1997—2006年北京协和医院确诊的7例肺郎格罕细胞组织细胞增多症的临床资料。结果7例患者均为男性,平均年龄26.7岁,其中4例吸烟,主要症状为咳嗽、活动后气短,5例在疾病过程中发生气胸。肺功能示阻塞性通气功能障碍3例、限制性通气功能障碍2例、混合性通气功能障碍2例,4例有不同程度的弥散功能障碍。胸部高分辨CT(HRCT)示6例表现为双上中肺野网格状改变及囊性变,仅有1例可见小结节影。外科肺活检标本病理学检查结果示7例光镜下均可见病理性郎格罕细胞浸润,6例可见囊样及气腔样结构。免疫组化阳性检出情况为7例S-100均为阳性;5例行CD1a检查者中4例阳性;6例行CD68检查者中5例阳性。结论肺郎格罕细胞组织细胞增多症常见于年轻吸烟男性,主要临床表现为咳嗽、活动后气短、反复气胸,胸部HTCT表现为双上中肺野为主的网结节或囊性变,肺功能无特异性改变,可伴有弥散功能异常,病理学检查可见病理性郎格罕细胞或免疫组化CD1a、S-100阳性可以明确诊断。     

Pulmonary lymphangioleiomyomatosis. A study of 69 patients. Groupe d'Etudes et de Recherche sur les Maladies "Orphelines" Pulmonaires (GERM"O"P).

Pulmonary lymphangioleiomyomatosis (LAM) is a rare disorder of unknown cause characterized by peribronchial, perivascular, and perilymphatic proliferation of abnormal smooth muscle cells leading to cystic lesions. The hypothesis of hormonal dependence and the effectiveness of hormonal therapy have not yet been demonstrated conclusively, and the prevalence of extrathoracic manifestations and the survival of patients with LAM are somewhat contradictory. A multicentric retrospective study was conducted in an attempt to describe better the initial features, the diagnostic procedures, the associated lesions, and, above all, the management and course of LAM in a large homogeneous series of 69 stringently selected patients, with a majority of cases diagnosed since 1990. The aim of the study, based on a review of the literature, also was to provide a comprehensive view of this uncommon disease. The clinical features were in keeping with previous studies, but we found that exertional dyspnea and pneumothorax were the most common features, and chylous involvement was less frequent. LAM was diagnosed after menopause in about 10% of cases. The onset of LAM occurred during pregnancy in 20% of cases, and a clear exacerbation of LAM was observed in 14% of cases during pregnancy. Pulmonary LAM was diagnosed on lung histopathology in 83% of cases, but renal angiomyolipoma, observed in 32% of our patients, may be a useful diagnostic criterion when associated with typical multiple cysts on chest CT scan or with chylous effusion. Chest CT scan was more informative than chest X-ray (normal in 9% of cases), and may be indicated in spontaneous pneumothorax or renal angiomyolipoma in women of childbearing age. About 40% of the patients had a normal initial spirometry, while an obstructive ventilatory defect (44%), a restrictive ventilatory defect (23%), was observed in other patients. Initial diffusing capacity for carbon monoxide was frequently decreased (82%). Hormonal therapy was administered in 57 patients, but a clear > or = 15% improvement of FEV1 was observed in only 4 evaluable patients, treated with tamoxifen and progestogens (n = 2), progestogen (n = 1), and oophorectomy (n = 1). Probably 1 of the most urgent needs for clinical research in LAM is to test the currently available hormonal treatments in the context of international multicenter prospective controlled studies. Pleurodesis was performed in 40 patients. Lung transplantation was performed in 13 patients, 7.8 +/- 5.2 years after onset of LAM, in whom the mean FEV1 was 0.57 +/- 0.15 L. After a follow-up of 2.3 +/- 2.2 years, 9 patients were alive. Mean follow-up from onset of disease to either death or closing date was 8.2 +/- 6.3 years. Overall survival was better than usually reported in LAM, and Kaplan-Meier plot showed survival probabilities of 91% after 5 years, 79% after 10 years, and 71% after 15 years of disease duration.     

Efficacy and safety of transbronchial lung biopsy for the diagnosis of lymphangioleiomyomatosis: A report of 24 consecutive patients

Background and objective

Lymphangioleiomyomatosis (LAM) is a diffuse cystic lung disease that occurs in women of childbearing age. LAM can be diagnosed on a clinical basis in patients with typical high‐resolution computed tomography (HRCT) patterns and at least one other corroborating disease feature, such as chylothorax, angiomyolipoma, tuberous sclerosis complex or elevated serum vascular endothelial growth factor (VEGF)‐D. However, patients who do not meet these criteria require tissue confirmation for a definitive diagnosis, and the utility of methods that are less invasive than surgical lung biopsy, such as transbronchial lung biopsy (TBLB), are not well studied. We retrospectively studied the efficacy and safety of TBLB for the diagnosis of LAM.

Methods

From January 1991 to August 2015, 131 consecutive LAM patients were prospectively registered in our study, and a TBLB was conducted for 24 patients. We retrospectively studied the yield and safety of TBLB in this cohort.

Results

All 24 patients were women; the median age was 42 years. HRCT showed multiple round thin‐walled cysts diffusely scattered throughout the lungs. The median level of serum VEGF‐D was 2109 pg/mL. Characteristic pathological findings for LAM were identified in 17 patients (70.8%) by two expert pathologists. The %predicted value for diffusing capacity of carbon monoxide was significantly lower in the 17 TBLB‐positive LAM patients compared to the seven TBLB‐negative LAM patients (P = 0.046). There were no serious adverse events such as pneumothorax or uncontrollable bleeding due to TBLB.

Conclusion

TBLB is a safe and effective method for the pathological diagnosis of LAM.

     

Do high-resolution CT findings of usual interstitial pneumonitis obviate lung biopsy? Views of pulmonologists

BACKGROUND: High-resolution CT (HRCT) of the lungs has become an essential component to evaluate patients with diffuse lung disease. Little is known, however, about the current practices of pulmonologists caring for patients with these complex conditions, and, in particular, whether HRCT can obviate the need for surgical lung biopsy. OBJECTIVES: To investigate the practices of pulmonologists concerning the acceptability of a HRCT diagnosis in lieu of lung biopsy in diffuse lung disease. METHODS: We asked practicing pulmonologists among membership of the American College of Chest Physicians whether HRCT results could replace lung biopsy in 16 diffuse lung diseases. Responses were examined in light of published evidence, practice guidelines, and certain practice parameters. RESULTS: Two hundred and thirty (52.6%) of 437 eligible physicians responded. Sixty-seven percent (67%) of respondents accepted HRCT diagnosis for idiopathic pulmonary fibrosis/usual interstitial pneumonia (IPF/UIP) despite their awareness of guidelines recommending histological diagnosis. Most would not accept a radiologic diagnosis for lymphangioleiomyomatosis (LAM; 37%) or eosinophilic granuloma (Langerhans' cell histiocytosis, LCH; 19%), even though CT findings are frequently characteristic. Responses were similar by type of clinical practice and recency of fellowship training. Chest physicians who referred patients for HRCT more frequently were more likely to accept HRCT diagnosis (p=0.008) and those who had higher self-ratings of proficiency in reading HRCT (p = 0.004) were more likely to believe HRCT often suggests specific diagnosis. CONCLUSIONS: Most US pulmonologists will accept an HRCT diagnosis of IPF/UIP without lung biopsy, but are reluctant to do so for most other diffuse lung conditions including LAM and LCH.