Micronodular Pneumocyte Hyperplasia Research Articles

Lung adenocarcinoma in a case of tuberous sclerosis complex with multifocal micronodular pneumocyte hyperplasia

Lung adenocarcinoma in a case of tuberous sclerosis complex with multifocal micronodular pneumocyte hyperplasia

Difficulties in Differentiating Osteosclerosis in Patients With Multifocal Micronodular Pneumocyte Hyperplasia and Cancer

A 52-year-old woman with multifocal micronodular pneumocyte hyperplasia in bilateral lungs and multiple sclerotic bone lesions (SBLs) visited our hospital. Tuberous sclerosis complex (TSC) was suspected but did not meet the diagnostic criteria. Ten years later, at age 62, the patient developed ureteral cancer. Cisplatin-containing chemotherapy ameliorated ureteral tumor, concomitant with exacerbation of SBLs. It was difficult to distinguish whether the exacerbation of SBLs was due to exacerbation of TSC or bone metastasis of cancer. The administration of cisplatin made the diagnosis even more difficult because its molecular biological effects can exacerbate the complications of TSC.

Multifocal Micronodular Pneumocyte Hyperplasia in Tuberous Sclerosis: an 8-Year CT Follow-Up

Although the most common pulmonary manifestation of tuberous sclerosis complex (TSC) is lymphangiomyomatosis, multifocal micronodular pneumocyte hyperplasia (MMPH) can also be seen in up to half of the patients with TSC. Computed tomography is the modality of choice for diagnosis and follow-up of MMPH which is typically appear as multiple, subcentimeter, randomly distributed solid and groundglass nodules. The awareness of this entity in patients with TSC will avoid unnecessary further work-up for underlying infectious or neoplastic causes.

Prevalence of thoracoabdominal imaging findings in tuberous sclerosis complex

BackgroundTuberous sclerosis complex (TSC) results in neurodevelopmental phenotypes, benign tumors, and cysts throughout the body. Recent studies show numerous rare findings in TSC. Guidelines suggest routine abdominal and chest imaging to monitor these thoracoabdominal findings, but imaging is not uniformly done across centers. Thus, the prevalence of many findings is unknown. To answer this, we categorized the clinical reads of 1398 thoracoabdominal scans from 649 patients of all ages in the Cincinnati Children’s Hospital TSC Repository Database.ResultsTypical TSC findings were present in many patients: kidney cysts (72%), kidney fat-containing angiomyolipomas (51%), kidney lipid-poor angiomyolipomas (27%), liver angiomyolipomas (19%), and lung nodules thought to represent multifocal micronodular pneumocyte hyperplasia (MMPH) (18%). While many features were more common in TSC2 patients, TSC1 patients had a higher prevalence of MMPH than TSC2 patients (24% versus 13%, p = 0.05). Many rare findings (e.g., lymphatic malformations and liver masses) are more common in TSC than in the general population. Additionally, most thoracoabdominal imaging findings increased with age except kidney cysts which decreased, with the 0–10 years age group having the highest percentage (69% 0–10 years, 49% 10–21 years, 48% 21 + years, p < 0.001). Finally, in our population, no patients had renal cell carcinoma found on abdominal imaging.ConclusionsThese results show that regular thoracoabdominal scans in TSC may show several findings that should not be ignored or, conversely, over-reacted to when found in patients with TSC. Female sex, TSC2 mutation, and age are risk factors for many thoracoabdominal findings. The data suggest novel interactions of genetic mutation with pulmonary nodules and age with renal cysts. Finally, in agreement with other works, these findings indicate that several rare thoracoabdominal imaging findings occur at higher rates in the TSC population than in the general population. This work supports obtaining detailed thoracoabdominal imaging in patients with TSC.

Multifocal micronodular pneumocyte hyperplasia lacking typical clinical features of the tuberous sclerosis complex: a case report and literature review

BackgroundMultifocal micronodular pneumocyte hyperplasia (MMPH) is a rare pulmonary manifestation of the tuberous sclerosis complex (TSC) with distinctive histological characteristics. Most case reports of MMPH associated with TSC usually have a history and typical clinical features (seizures, mental retardation, and skin lesions) of TSC. We present a peculiar asymptomatic MMPH case that lacked the history and typical clinical features of TSC.Case presentationA 56-year-old man was referred to our hospital with bilateral ground-glass opacities (GGOs) on chest computed tomography (CT) lasting 8 months, with no complaint of any discomfort. Because of the lack of clinical manifestations, the diagnosis of MMPH and TSC was confirmed by lung biopsy histopathology and gene sequencing of nonsense mutations in the TSC1 gene. Considering the relevant literature review and that the prognosis of most patients with MMPH is generally stable, no special treatment was given. We followed up with the patient for three years after discharge, and the clinical manifestations and imaging features of the patient were stable.ConclusionTo our best knowledge, this is the first case of MMPH lacking typical clinical manifestations of TSC confirmed by histopathology combined with gene sequencing. MMPH should be considered as one of the differential diagnoses of multiple GGOs in the lung even when the findings of TSC are not recognized.

February 2022 Medical Image of the Month: Multifocal Micronodular Pneumocyte Hyperplasia in the Setting of Tuberous Sclerosis

No abstract available. Article truncated at 150 words. A 22-year-old man with a known diagnosis of Tuberous Sclerosis Complex (TSC) presents for a follow-up unenhanced chest CT to re-evaluate pulmonary nodules seen in the lung bases on a prior abdominal CT. The patient also has a history of multiple renal lesions consistent with lipid-poor angiomyolipomas based on previous abdominal MRI findings. The chest CT demonstrated multiple scattered, randomly distributed sub-centimeter pulmonary nodules of solid or subsolid morphology [Figure 1A]. Those nodules visible in the lung bases on the prior abdominal CT had remined stable over the 12-month interval consistent with multifocal microscopic pneumocyte hyperplasia (MMPH)[Figure 1B,C]. Myocardial fatty foci (MFF) were visualized in the heart on soft tissue window display settings [Figure 2A] as were multiple scattered sclerotic bone lesions on bone window display settings [Figure 2B,C]. No pulmonary cysts were seen to suggest lymphangioleiomyomatosis (LAM) and there were no thoracic lymphangiomas. MMPH represents a benign hamartomatous proliferation …

Multifocal micronodular pneumocyte hyperplasia with a novel mutation in TSC1: a case report

We report on a 34-year-old woman diagnosed with tuberous sclerosis complex. The patient was admitted for respiratory manifestations, while multi-organ involvement made the diagnostic process challenging. Genetic testing revealed a novel mutation TSC1 c.2094_2110del (p.His699Ter), which expands the disease-causing variant spectrum. Our results may facilitate the disease diagnostics and help to devise genetic counseling and targeted gene therapy.

Tuberous Sclerosis: Current Update.

Tuberous sclerosis complex (TSC) is a relatively rare autosomal dominant neurocutaneous disorder secondary to mutations in the TSC1 or TSC2 tumor suppressor genes. Although manifestation of the classic triad of seizures, intellectual disability, and facial angiofibromas may facilitate timely diagnosis of TSC, the multisystem features that may indicate TSC in the absence of these manifestations remain highly variable. In addition, patients with TSC are at risk of developing multiple benign and malignant tumors in various organ systems, resulting in increased morbidity and mortality. Thus, imaging plays a critical role in diagnosis, surveillance, and management of patients with TSC. It is crucial that radiologists be familiar with TSC and the various associated imaging features to avoid a delayed or incorrect diagnosis. Key manifestations include cortical dysplasias, subependymal nodules, subependymal giant cell astrocytomas, cardiac rhabdomyomas, lymphangioleiomyomatosis, and angiomyolipomas. Renal angiomyolipomas in particular can manifest with imaging features that mimic renal malignancy and pose a diagnostic dilemma. Other manifestations include dermatologic and ophthalmic manifestations, renal cysts, renal cell carcinomas, multifocal micronodular pneumocyte hyperplasia, splenic hamartomas, and other rare tumors such as perivascular epithelioid tumors. In addition to using imaging and clinical features to confirm the diagnosis, genetic testing can be performed. In this article, the molecular pathogenesis, clinical manifestations, and imaging features of TSC are reviewed. Current recommendations for management and surveillance of TSC are discussed as well. ©RSNA, 2021.

Tuberous sclerosis complex for the pulmonologist.

Tuberous sclerosis complex (TSC) is a rare multisystem genetic disorder affecting almost all organs with no sex predominance. TSC has an autosomal-dominant inheritance and is caused by a heterozygous mutation in either the TSC1 or TSC2 gene leading to hyperactivation of the mammalian target of rapamycin (mTOR). TSC is associated with several pulmonary manifestations including lymphangioleiomyomatosis (LAM), multifocal micronodular pneumocyte hyperplasia (MMPH) and chylous effusions. LAM is a multisystem disorder characterised by cystic destruction of lung parenchyma, and may occur in either the setting of TSC (TSC-LAM) or sporadically (S-LAM). LAM occurs in 30-40% of adult females with TSC at childbearing age and is considered a nonmalignant metastatic neoplasm of unknown origin. TSC-LAM is generally milder and, unlike S-LAM, may occur in males. It manifests as multiple, bilateral, diffuse and thin-walled cysts with normal intervening lung parenchyma on chest computed tomography. LAM is complicated by spontaneous pneumothoraces in up to 70% of patients, with a high recurrence rate. mTOR inhibitors are the treatment of choice for LAM with moderately impaired lung function or chylous effusion. MMPH, manifesting as multiple solid and ground-glass nodules on high-resolution computed tomography, is usually harmless with no need for treatment.

A Case of Tuberous Sclerosis with Multifocal Micronodular Pneumocyte Hyperplasia Diagnosed by Bronchoscopy

A Case of Tuberous Sclerosis with Multifocal Micronodular Pneumocyte Hyperplasia Diagnosed by Bronchoscopy

Lymphangioleiomyomatosis Association with Underlying Genotype in Patients with Tuberous Sclerosis Complex.

Rationale: Lymphangioleiomyomatosis (LAM) is a female-predominant lung disease caused by mutations in the tuberous sclerosis complex (TSC) genes TSC1 and TSC2.Objectives: To examine the association between TSC mutation subtypes and the prevalence of LAM in women with TSC.Methods: Adult women seen at the Cincinnati Children's Hospital Medical Center's TSC clinic were stratified into the following three groups: those with TSC1 mutation, those with TSC2 mutation, and those with no mutation identified (NMI). Individual TSC manifestations were ascertained by blinded review of chest computed tomographic scans (LAM, multifocal micronodular pneumocyte hyperplasia, and sclerotic bone lesions) and chart review (all other manifestations). The association between mutation status and TSC manifestations was assessed by the Wilcoxon rank-sum test.Results: Our cohort consisted of 55 TSC women, including 30/55 (55%) with TSC2, 12/55 (22%) with TSC1, and 13/55 (23%) with NMI. Twenty-three women (42%) had characteristic cysts consistent with LAM, of whom 16 had TSC2 mutations and seven had NMI. The prevalence of LAM was higher in women with TSC2 mutations compared with women with TSC1 mutations (16/29 [55%] vs. 0/12; P = 0.003). Similarly, renal angiomyolipomas were more common in women with TSC2 mutations compared with women with TSC1 mutations (29/30 [97%] vs. 6/12 [50%]; P = 0.01). There was no association between TSC mutation subtype and the presence of multifocal micronodular pneumocyte hyperplasia, sclerotic bone lesions, and skin or brain involvement. Serum VEGF-D (vascular endothelial growth factor-D) concentrations (median [95% confidence interval]) tended to be higher in patients harboring TSC2 mutations compared with patients with TSC1 mutations (725 pg/ml [612-1,317] vs. 331 pg/ml [284-406]; P = 0.03) and in patients with LAM compared with patients without LAM (725 pg/ml [563-1,609] vs. 429 pg/ml [357-773]; P = 0.02).Conclusions: LAM and angiomyolipomas are more common in women with TSC harboring TSC2 mutations compared with women with TSC1 mutations. Serum VEGF-D is a useful biomarker to suggest the presence of LAM in women with TSC.

Tuberous sclerosis related-lesions detected by postmortem computed tomography

Abstract Tuberous sclerosis (TS) is an autosomal-dominant inherited neurocutaneous syndrome characterized by the presence of hamartomatous lesions in organs such as the skin, eye, brain, lung, heart, kidney and bone. Since evaluation of this disorder has been revolutionized by computed tomography (CT) and magnetic resonance imaging (MRI), the radiologic manifestations of TS have become clinically important for diagnosis. However, it has remained unclear whether postmortem computed tomography (PMCT) is available for recognition of the various organ manifestations of TS in deceased individuals. We present two autopsy cases in which PMCT indicated subependymal calcified tuberous lesions in the brain, cysts or multiple tiny nodules associated with lymphangiomyomatosis or multifocal micronodular pneumocyte hyperplasia in the lungs, respectively, angiomyolipoma in the kidneys, lipoma in the liver, multiple sclerotic lesions in the pelvis and vertebrae, and scoliosis. Such lesions are characteristic of TS. In this way we were able to confirm the validity of PMCT for demonstrating lesions associated with TS in these two cases, and its usefulness for complementing the findings of autopsy in patients with TS.

Lymphangioleiomyomatosis and Micronodular Pneumocyte Hyperplasia in a Patient With Tuberous Sclerosis Complex

Abstract Lymphangioleiomyomatosis (LAM) is a rare progressive disease characterized by proliferation of smooth muscle–like cells in the lung, mediastinum, and abdomen. In the lung, it is seen with cystic destruction of the lung parenchyma, which occurs almost exclusively in premenopausal women. It occurs in about 1% of patients with tuberous sclerosis complex (TSC). MNPH is an extremely rare pulmonary manifestation of TSC, comprising type 2 pneumocytes in a pattern resembling bronchioloalveolar adenocarcinoma. We report a case of both pulmonary LAM and MNPH associated with TSC. A 35-year-old female with a past medical history of TSC with multiple complications was admitted with iatrogenic pneumothorax following nasopharyngeal intubation during a dental procedure. A blebectomy with wedge resection and mechanical pleurodesis was performed. On gross examination, the wedge specimens revealed multiple cysts in a random distribution. Microscopic examination of the lung parenchyma revealed prominent smooth muscle cells with focal nodule formation. Immunohistochemical stains for SMA and HMB-45 were found to be positive and corroborated these findings. Areas of localized nodular proliferation of benign cuboidal type II pneumocytes lining alveolar walls were also identified. These findings are consistent with LAM and MNPH. Clinicopathological correlation with surgical investigation is indispensable in diagnosing LAM and MNPH, especially when radiologic findings are not definitive in these entities.

Pulmonary manifestations in tuberous sclerosis complex.

Tuberous sclerosis complex has manifestations in many organ systems, including brain, heart, kidney, skin, and lung. The primary manifestations in the lung are lymphangioleiomyomatosis (LAM) and multifocal micronodular pneumocyte hyperplasia (MMPH). LAM affects almost exclusively women, and causes cystic lung destruction, pneumothorax, and chylous pleural effusions. LAM can lead to dyspnea, oxygen dependence, and respiratory failure, with more rapid disease progression during the premenopausal years. In contrast, MMPH affects men and women equally, causing small nodular pulmonary deposits of type II pneumocytes that rarely progress to symptomatic disease. Here, we review the clinical features and pathogenesis of LAM and MMPH.

Clinical Course of Histologically Proven Multifocal Micronodular Pneumocyte Hyperplasia in Tuberous Sclerosis Complex: A Case Series and Comparison with Lymphangiomyomatosis

Background: Multifocal micronodular pneumocyte hyperplasia (MMPH) is a rare pulmonary manifestation of tuberous sclerosis complex (TSC). Because of its rarity, no previous study has described the detailed clinical course of this disease. Objectives: This study aimed to clarify the longitudinal clinical characteristics of subjects with MMPH. Methods: Nine patients with MMPH diagnosed at Hokkaido University Hospital were retrospectively analyzed. Changes in computed tomography findings and pulmonary function were compared during the follow-up period. Serum levels of KL-6, surfactant protein (SP)-A, and SP-D were measured to clarify their potentials as blood biomarkers of the disease. Fourteen cases of lymphangiomyomatosis (LAM) were also included to compare their clinical characteristics with those of subjects with MMPH. Results: Of the 9 patients, 7 were female and 2 were male. The median age at diagnosis was 43 years (range, 19–56), and all cases were diagnosed following incidental abnormal radiographic findings. During the follow-up, 1 patient died of lung cancer, but others were radiographically stable and had stable pulmonary function. Serum levels of SP-A in 5 patients (mean, 146.4 ng/mL) and SP-D in 6 patients (mean, 337.3 ng/mL) were elevated in subjects with MMPH, whereas KL-6 levels were within the reference range (mean, 230 U/mL) in all patients. Levels of SP-A and SP-D were significantly higher in subjects with MMPH than those with LAM (p < 0.05). Conclusions: Radiographic findings and pulmonary function were stable in all cases of MMPH. Serum SP-A and SP-D, but not KL-6, may be useful markers for suspicion of the presence of MMPH in patients with TSC.

Lymphangioleiomyomatosis, multifocal micronodular pneumocyte hyperplasia, and sarcoidosis: more pathological findings in the same chest CT, or a single pathological pathway?

BackgroundAutoimmune hepatitis/primary biliary cirrhosis overlap syndrome, lymphangioleiomyomatosis/tuberous sclerosis complex (LAM-TSC), and sarcoidosis are three rare diseases. Here we present, to the best of our knowledge, the first description of a patient with the coexistence of these three diseases.Case presentationA 47-year-old woman affected by LAM-TSC and primary biliary cirrosis/autoimmune hepatitis overlap syndrome. During her follow up a high resolution chest CT scan (HRTC) confirmed the presence of both multiple cysts and micronodular opacities consistent with multifocal micronodular pneumocytes hyperlasia (MMPH), and revealed multiple hilar-mediastinal symmetrical lymphadenopathies suggestive of sarcoidosis. Simultaneously, subcutaneous nodules appeared on her forearm bilaterally. Cutaneous biopsy showed granulomatous dermatitis with sarcoid-like granulomas. A diagnosis of stage I pulmonary sarcoidosis was made. No treatment for sarcoidosis was initiated since the patient had neither systemic involvement, nor respiratory impairment.ConclusionsThe presence of more than one rare disease should challenge the concept of a potential common underlying mechanism, since the a priori probability of the concomitant presence of different conditions with different pathogenic mechanisms - especially if rare diseases - is low.We speculate that the dysregulation of the pathway involving mTOR and MAPK and their interaction might play a role in the pathogenesis of other diseases, including sarcoidosis.

Women with TSC: Relationship between Clinical, Lung Function and Radiological Features in a Genotyped Population Investigated for Lymphangioleiomyomatosis.

The advent of pharmacological therapies for lymphangioleiomyomatosis (LAM) has made early diagnosis important in women with tuberous sclerosis complex (TSC), although the lifelong cumulative radiation exposure caused by chest computer tomography (CT) should not be underestimated. We retrospectively investigated, in a cohort of TSC outpatients of San Paolo Hospital (Milan, Italy) 1) the role of pulmonary function tests (PFTs) for LAM diagnosis, 2) the association between LAM and other features of TSC (e.g. demography, extrapulmonary manifestations, genetic mutations, etc.), and 3) the characteristics of patients with multifocal micronodular pneumocyte hyperplasia (MMPH). Eighty-six women underwent chest CT scan; pulmonary involvement was found in 66 patients (77%; 49% LAM with or without MMPH, and 28% MMPH alone). LAM patients were older, with a higher rate of pneumothorax, presented more frequently with renal and hepatic angiomyolipomas, and tended to have a TSC2 mutation profile. PFTs, assessed in 64% of women unaffected by cognitive impairments, revealed a lower lung diffusion capacity in LAM patients. In multivariate analysis, age, but not PFTs, resulted independently associated with LAM diagnosis. Patients with MMPH alone did not show specific clinical, functional or genetic features. A mild respiratory impairment was most common in LAM-TSC patients: In conclusions, PFTs, even if indicated to assess impairment in lung function, are feasible in a limited number of patients, and are not significantly useful for LAM diagnosis in women with TSC.

Pulmonary Neoplasms in Patients with Birt-Hogg-Dubé Syndrome: Histopathological Features and Genetic and Somatic Events.

Birt-Hogg-Dubé syndrome (BHD) is an inherited disorder caused by genetic mutations in the folliculin (FLCN) gene. Individuals with BHD have multiple pulmonary cysts and are at a high risk for developing renal cell carcinomas (RCCs). Currently, little information is available about whether pulmonary cysts are absolutely benign or if the lungs are at an increased risk for developing neoplasms. Herein, we describe 14 pulmonary neoplastic lesions in 7 patients with BHD. All patients were confirmed to have germline FLCN mutations. Neoplasm histologies included adenocarcinoma in situ (n = 2), minimally invasive adenocarcinoma (n = 1), papillary adenocarcinoma (n = 1), micropapillary adenocarcinoma (n = 1), atypical adenomatous hyperplasia (n = 8), and micronodular pneumocyte hyperplasia (MPH)-like lesion (n = 1). Five of the six adenocarcinoma/MPH-like lesions (83.3%) demonstrated a loss of heterozygosity (LOH) of FLCN. All of these lesions lacked mutant alleles and preserved wild-type alleles. Three invasive adenocarcinomas possessed additional somatic events: 2 had a somatic mutation in the epidermal growth factor receptor gene (EGFR) and another had a somatic mutation in KRAS. Immunohistochemical analysis revealed that most of the lesions were immunostained for phospho-mammalian target of rapamycin (p-mTOR) and phospho-S6. Collective data indicated that pulmonary neoplasms of peripheral adenocarcinomatous lineage in BHD patients frequently exhibit LOH of FLCN with mTOR pathway signaling. Additional driver gene mutations were detected only in invasive cases, suggesting that FLCN LOH may be an underlying abnormality that cooperates with major driver gene mutations in the progression of pulmonary adenocarcinomas in BHD patients.

Rare Lung Manifestation of Multifocal Micronodular Pneumocyte Hyperplasia in a Teenage Girl with Tuberous Sclerosis Complex

Rare Lung Manifestation of Multifocal Micronodular Pneumocyte Hyperplasia in a Teenage Girl with Tuberous Sclerosis Complex

Lymphangioleiomyomatosis and multifocal micronodular pneumocyte hyperplasia in Japanese patients with tuberous sclerosis complex.

Pulmonary involvement in tuberous sclerosis complex (TSC) includes lymphangioleiomyomatosis (LAM) and multifocal micronodular pneumocyte hyperplasia (MMPH). This retrospective study investigated pulmonary involvement in Japanese TSC patients and pulmonary function testing in TSC-LAM. The study subjects included 59 TSC patients (age range: 13-66, 15 males and 44 females). Female patients were divided into 3 groups (Group 1: symptomatic LAM, Group 2: asymptomatic LAM, Group 3: without LAM) and 3 cystic grades according to increasing cyst numbers on computed tomography images (patients without LAM, Grade 1 patients, and Grade 2+Grade 3 patients). The results of pulmonary function tests were compared among the groups and the grades. One male (6.7%) patient and 19 female (43.2%) patients were diagnosed with LAM and 7 male (43.2%) and 23 female (52.3%) patients were diagnosed with MMPH. Patients with multiple pulmonary nodules had higher rates of renal angiomyolipoma and history of seizures than patients without nodules. Although all 6 adolescent patients displayed no pulmonary symptoms, MMPH was found in 3 patients and LAM was found in a 13-year-old girl. Carbon monoxide diffusing capacity (DLco) differed significantly among the 3 groups and DLco and carbon monoxide diffusing capacity divided by the alveolar volume (DLco/VA) differed significantly among the 3 cystic grades. There was no difference in the prevalence of pulmonary involvement in TSC patients among countries. LAM and MMPH occur even during adolescence in TSC patients. DLco and the number of cysts are useful predictors of onset and progression of TSC-LAM.