Pulmonary Alveolar Microlithiasis

Successful bilateral lung transplantation in pulmonary alveolar microlithiasis: A case report and review of literature

BACKGROUND

Pulmonary alveolar microlithiasis (PAM) is a rare autosomal recessive genetic disorder with approximately 1000 known cases worldwide, in which calcium phosphate microliths deposit in the alveolar air spaces. As of writing this report, no definitive conventional therapy exists, and many PAM cases may progress to severe respiratory failure and potential death. Bilateral lung transplantation (BLx) seems to be the most optimal solution; however, this procedure is challenging along with limited reports regarding the outcome in PAM. We report a case of PAM successfully treated with BLx for the first time in Iran.

METHOD

We present the case of a 42-year-old female with a longstanding history of cough, not responding to conventional antitussive medication, who was diagnosed as a case of PAM following a hospitalization due to coughing, dyspnea on exertion, and hemoptysis. Despite treatment with corticosteroid and medical treatment, no improvement was achieved and she subsequently developed respiratory and right ventricular failure, with oxygen ventilation dependence. Eventually, she was scheduled for BLx. The operation was successful and during her 2-year follow-up, no recurrence or significant postoperative complications has been reported.

CONCLUSION

This case presentation and literature review confirm the effectiveness of BLx as a promising treatment for PAM-diagnosed patients, improving both life expectancy and quality of life.

Severe pulmonary hypertension in pulmonary alveolar microlithiasis: A comprehensive literature review

This review focuses on Pulmonary Alveolar Microlithiasis (PAM), an autosomal recessive genetic disorder characterized by calcium crystal deposits (microliths) resulting from loss of function of the SLC34A2 gene. PAM is a rare disease with approximately 1100 reported cases globally. The historical context of its discovery and the genetic, epidemiological, and pathophysiological aspects are discussed. PAM falls under interstitial lung diseases and is associated with pulmonary hypertension (PH), primarily categorized as Group 3 PH. The clinical manifestations, diagnostic approaches, and challenging aspects of treatment are explored. A clinical case of PAM with severe pulmonary hypertension is presented, emphasizing the importance of comprehensive evaluation and the potential benefits of phosphodiesterase-5 inhibitors (PDE5i) therapy. Despite limited therapeutic options and challenging diagnosis, this review sheds light on recent developments and emerging treatments for PAM and associated pulmonary hypertension.

Outcome of lung transplantation in patients with pulmonary alveolar microlithiasis in the era of COVID-19 infection

Lung transplant recipients are at higher risk of developing COVID-19 infection compared to other solid organ transplants. The risk further increases in the unvaccinated patients. We present a case of a 43-year-old male who underwent bilateral sequential lung transplantation for pulmonary alveolar microlithiasis (PAM) and had an uneventful recovery. However, two years post-transplantation, the patient developed chronic lung allograft dysfunction (CLAD) with bronchiolitis obliterans syndrome and two episodes of COVID-19 infection. During the second episode of COVID-19 infection, the patient developed sepsis and multi-organ dysfunction ultimately resulting in death. Our case report highlights the increased susceptibility of PAM patients' post-lung transplant to COVID-19 infection. Continuous follow-up of PAM patients' post-lung transplantation is necessary to prevent unfavorable outcomes.

Pulmonary Alveolar Microlithiasis in Children Less than 5 Years of Age

OBJECTIVE

To collect all published cases up to January 2019 of pulmonary alveolar microlithiasis (PAM) in patients age 5 years and under and to compare their characteristics with those of the 1022 cases in the most recent all-age cohort published in 2015.

STUDY DESIGN

We identified 28 cases of PAM worldwide in children age 5 years and under, accounting for only 2%-3% of all cases.

RESULTS

Children seem more frequently symptomatic, notably with more cough and severe acute respiratory failure, but had no reported extrapulmonary manifestation. Children with PAM evidenced less typical radiologic findings, with frequent ground glass opacities not reported in adult cases and milder calcifications as less frequent, smaller, and mainly restricted to the lower lobes.

CONCLUSIONS

PAM remains an uncommon diagnosis in young children, as symptoms and radiologic findings are less specific. Physicians should be aware to look for calcifications in chest computed tomography at mediastinal window and avoid elution of the bronchoalveolar lavage to find microliths. Collecting longitudinal data through an international registry would help in characterizing PAM to predict disease progression and plan lung transplantation.

Pulmonary alveolar microlithiasis: Incidental finding - should we Ignore?

Pulmonary alveolar microlithiasis (PAM) is a rare entity, presenting mostly as an incidental finding. This disease has an autosomal recessive inheritance with inactivating mutations in the gene “solute carrier family 34 member 2”. The present study was conducted to bring attention to this rare though preventable disease. The study was a cross-sectional descriptive study, conducted at the Department of Pathology, of a tertiary care hospital in New Dehli-India. PAMs were incidentally seen in two patients diagnosed with micronodular hepatic cirrhosis leading to reanalysis of 212 autopsies, retrospectively. Statistical analysis was done using Stata 14.0. We observed three forms (Type A, B and C) of round hyaline bodies measuring in diameter with thin delicate, radiating fibrils. These bodies were PAS positive, showed black discolouration of the pigment with von Kossa stain and birefringence on polarized microscopy using Congo red stain, however the refringence was light green as compared to apple green birefringence seen with amyloid deposition. PAM has a slow progressive course leading to a high rate of incidental detection. Drugs known to inhibit the micro-crystal growth of hydroxyapatite may slow the disease progression. The family members of patients with PAM may also be kept on follow up with regular imaging. Key messages: It is important to bring out the incidental finding as, seemingly innocuous observations may provide valuable insight into incurable diseases, especially rare diseases.

Pulmonary Alveolar Microlithiasis: AIRP Best Cases in Radiologic-Pathologic Correlation

Editor's Note.-RadioGraphics continues to publish radiologic-pathologic case material selected from the American Institute for Radiologic Pathology (AIRP) "best case" presentations. The AIRP conducts a 4-week Radiologic Pathology Correlation Course, which is offered five times per year. On the penultimate day of the course, the best case presentation is held at the American Film Institute Silver Theater and Cultural Center in Silver Spring, Md. The AIRP faculty identifies the best cases, from each organ system, brought by the resident attendees. One or more of the best cases from each of the five courses are then solicited for publication in RadioGraphics. These cases emphasize the importance of radiologic-pathologic correlation in the imaging evaluation and diagnosis of diseases encountered at the institute and its predecessor, the Armed Forces Institute of Pathology (AFIP).

A Case of Pulmonary Alveolar Microlithiasis Diagnosed by Transbronchial Biopsy

Pulmonary alveolar microlithiasis is a rare infiltrative pulmonary disease, in which intraalveolar accumulation of small stones (microliths) consisting of calcium phosphatite occurs. It is an autosomal recessive disorder. The disease occurs as a result of the disruption of type IIb sodium phosphate cotransporter in type II alveolar cells after the mutation of SLC34A2. Majority of patients are diagnosed between age 20 and 40. Here, we present a case of alveolar microlithiasis that was diagnosed with transbronchial biopsy.

Modeling pulmonary alveolar microlithiasis by epithelial deletion of the Npt2b sodium phosphate cotransporter reveals putative biomarkers and strategies for treatment

Pulmonary alveolar microlithiasis (PAM) is a rare, autosomal recessive lung disorder associated with progressive accumulation of calcium phosphate microliths. Inactivating mutations in SLC34A2, which encodes the NPT2b sodium-dependent phosphate cotransporter, has been proposed as a cause of PAM. We show that epithelial deletion of Npt2b in mice results in a progressive pulmonary process characterized by diffuse alveolar microlith accumulation, radiographic opacification, restrictive physiology, inflammation, fibrosis, and an unexpected alveolar phospholipidosis. Cytokine and surfactant protein elevations in the alveolar lavage and serum of PAM mice and confirmed in serum from PAM patients identify serum MCP-1 (monocyte chemotactic protein 1) and SP-D (surfactant protein D) as potential biomarkers. Microliths introduced by adoptive transfer into the lungs of wild-type mice produce marked macrophage-rich inflammation and elevation of serum MCP-1 that peaks at 1 week and resolves at 1 month, concomitant with clearance of stones. Microliths isolated by bronchoalveolar lavage readily dissolve in EDTA, and therapeutic whole-lung EDTA lavage reduces the burden of stones in the lungs. A low-phosphate diet prevents microlith formation in young animals and reduces lung injury on the basis of reduction in serum SP-D. The burden of pulmonary calcium deposits in established PAM is also diminished within 4 weeks by a low-phosphate diet challenge. These data support a causative role for Npt2b in the pathogenesis of PAM and the use of the PAM mouse model as a preclinical platform for the development of biomarkers and therapeutic strategies.

Pulmonary alveolar microlithiasis: review of the 1022 cases reported worldwide

Pulmonary alveolar microlithiasis (PAM) is a rare disease characterised by the widespread intra-alveolar accumulation of minute calculi called microliths. It is caused by mutation of the SLC34A2 gene encoding the type IIb sodium phosphate cotransporter in alveolar type II cells. The present study explores the epidemiological, familial, genetic, clinical, diagnostic, radiological and therapeutic aspects with the aim of contributing to a better understanding of this uncommon disease.

We searched articles on PAM published up to December 2014 and 544 papers were found, accounting for 1022 cases.

PAM is present in all continents and in many nations, in particular in Turkey, China, Japan, India, Italy and the USA. Familiality is frequent. The clinical course is not uniform and the causes of this clinical variability seem to be largely nongenetic. The optimal diagnostic procedure is the association of chest high-resolution computed tomography (HRCT) with bronchoalveolar lavage, but a chest radiograph may suffice in families in which a case has already been diagnosed. Moreover, chest radiography and HRCT allow the classification of the evolutionary phase of the disease and its severity. At present lung transplantation is the only effective therapy. However, better knowledge of the gene responsible offers hope for new therapies.

Familial, genetic, clinical, radiological and therapeutic aspects of pulmonary alveolarmicrolithiasis epidemiologyhttp://ow.ly/St3Mw

Pulmonary microlithiasis - A case report

Pulmonary alveolar microlithiasis is a rare diffuse lung disease characterized by widespread sand-like intra-alveolar calcifications (calcospherites composed of calcium and phosphorus). Around 800 cases have been reported in the literature to date. We report here a case of a 35 years old female with prolonged h/o of exertional dyspnoea and mild cough. Clinical examination was mostly normal. Her Chest X-Ray revealed bilateral multiple nodular opacities (sand storm appearance). CT Scan chest showed diffuse micronodular calcifications with septal thickening, compatible with alveolar microlithiasis. Pulmonary function tests showed moderately restrictive lung disease. Bronchoscopic alveolar lavage revealed calcospherites in the alveloli and bronchi confirming the diagnosis of pulmonary alveolar microlithiasis.

Diagnosis and treatment of pulmonary alveolar microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a rare genetic disease caused by mutations in sodium-phosphate co-transporter (SLC34A2), which encodes a type 2b sodium phosphate co-transporter. Disease is characterized by intra-alveolar microlith formation of phosphate. Turkey has a high prevalence of PAM. Herein, we report the clinical and radiological findings of three patients diagnosed with PAM and treated with disodium etidronate.

Pulmonary Alveolar Microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a rare autosomal recessive condition that is often asymptomatic despite significant changes in chest imaging. Diagnosis is often made when patients become symptomatic in adulthood. There are still no proven treatments, but earlier diagnosis may allow for evaluation of preventative strategies that could improve outcome. It is an important diagnosis to consider in children who have marked radiographic findings with no or very mild symptoms or physical findings. Diagnosis can be made with imaging alone but may necessitate lung biopsy for definitive diagnosis.

A rare indication for lung transplantation - pulmonary alveolar microlithiasis: institutional experience of five consecutive cases

BACKGROUND

Pulmonary alveolar microlithiasis (PAM) is a rare lung disease caused by calcifications within the alveolar space. The only known effective treatment for an end-stage PAM is lung transplantation (LuTX).

METHODS

We performed a retrospective chart review of all individuals that underwent lung transplantation at our center between 1989 and 2013. Five consecutive patients with PAM were identified.

RESULTS

Four females and one male with a mean age of 46.3 yr were identified. Extracorporeal membrane oxygenation (ECMO) support was required intraoperatively in four cases and post-operatively in one case. Mean post-operative intubation time was 3.3 (range, 2-5) d and mean intensive care unit (ICU) stay was 8.3 (range, 4-12) d. No intraoperative complications were observed. One early patient (operated in 1995) underwent acute re-transplantation on the second post-operative day (POD) and died from sepsis on the 11 POD. In one patient reperfusion edema was observed requiring a prolonged weaning process. No other severe perioperative complications were observed. Four of five patients are currently still alive with normal follow-up parameters. No recurrence of PAM was observed.

CONCLUSIONS

Lung transplantation is a feasible therapy option in patients with end-stage PAM showing good post-operative results comparable to other indications for LuTX.

Pulmonary Alveolar Microlithiasis - Clinico-Radiological dissociation - A case report with Radiological review

Pulmonary alveolar microlithiasis (PAM) is a rare chronic lung disease characterized by deposition of intra alveolar calcium and phosphate in bilateral lung parenchyma with predominance in lower and mid zones. Etiology and pathogenesis is not fully understood. However, mutation in SLC34A2 gene that encodes a sodium phosphate co-transporter in alveolar type-II cells resulting in formation and accumulation of microliths rich in calcium phosphate due to impaired clearance is considered the cause of disease. Patients with PAM are asymptomatic till development of hypoxemia and cor pulmonale. It remains static, while in some it progresses to pulmonary fibrosis, respiratory failure and cor pulmonale. We report a case of 44 year old male patient presenting with progressive shortness of breath on exertion for one year in duration with dry cough, more since last six months. Chest radiograph showed dense micronodular opacities giving classical sandstorm appearance. High resolution computed tomography (HRCT) showed microcalcification, subpleural cystic changes and calcified pleura. Lung biopsy showed calcospherites within alveolar spaces.

A pedigree with pulmonary alveolar microlithiasis: a clinical case report and literature review

Pulmonary alveolar microlithiasis (PAM) is a rare autosomal recessive disease characterized by the presence of innumerable calcium phosphate microliths in the alveoli. Clinical-radiological dissociation is an important hallmark of this disease. Most PAM patients are asymptomatic and pulmonary tissue changes are discovered incidentally. PAM is pathologically attributable to the formation and aggregation of calcium phosphate microliths in the alveoli after mutations in the SLC34A2 gene (the type IIb sodium-phosphate cotransporter gene) coding NaPi-IIb. In the clinical work, we discovered an inbred pedigree with PAM, which include four PAM siblings. We performed a sequence analysis of the SLC34A2 gene in all members of this PAM pedigree and found that a homozygous mutation c.575C > A (p.T192 K) in exon 6 was involved. To the best of our knowledge, this study was the first to discover nucleotide mutations in exon 6 in Asians.

The sodium-phosphate co-transporter SLC34A2, and pulmonary alveolar microlithiasis: Presentation of an inbred family and a novel truncating mutation in exon 3

Pulmonary alveolar microlithiasis is a disorder in which many tiny fragments (microliths) of calcium phosphate gradually accumulate in alveoli. Loss of function mutations in the gene SLC34A2 coding for the sodium phosphate co-transporter (NaPi-IIb) are responsible for genetic forms of alveolar microlithiasis. We now report a consanguineous Italian family from Calabria with two affected members segregating alveolar microlithiasis in a recessive fashion. We describe, for the first time, a novel loss of function mutation in the gene coding for NaPi-IIb. A careful description of the clinical phenotype is provided together with technical details for direct sequencing of the gene.

AS, Zanetti G, Marchiori E. Can chest high-resolution computed tomography findings diagnose pulmonary alveolar microlithiasis?

OBJECTIVE

The present study was aimed at retrospectively reviewing high-resolution computed tomography (HRCT) findings in patients with pulmonary alveolar microlithiasis in order to evaluate the frequency of tomographic findings and their distribution in the lung parenchyma.

MATERIALS AND METHODS

Thirteen patients (9 females and 4 males; age, 9 to 59 years; mean age, 34.5 years) were included in the present study. The HRCT images were independently evaluated by two observers whose decisions were made by consensus. The inclusion criterion was the presence of abnormalities typical of pulmonary alveolar microlithiasis at HRCT, which precludes lung biopsy. However, in 6 cases lung biopsy was performed.

RESULTS

Ground-glass opacities and small parenchymal nodules were the predominant tomographic findings, present in 100% of cases, followed by small subpleural nodules (92.3%), subpleural cysts (84.6%), subpleural linear calcifications (69.2%), crazy-paving pattern (69.2%), fissure nodularity (53.8%), calcification along interlobular septa (46.2%) and dense consolidation (46.2%).

CONCLUSION

As regards distribution of the lesions, there was preferential involvement of the lower third of the lungs. No predominance of distribution in axial and anteroposterior directions was observed.

Pulmonary alveolar microlithiasis: an interesting case report with systematic review of Indian literature

Pulmonary alveolar microlithiasis is a rare disease characterized by intra-alveolar presence of microliths. This study reports an interesting case of pulmonary alveolar microlithiasis and provides a systematic review of cases reported from India. A 23-year-old female presented with a history of cough, wheeze, chest pain, and episodic wheeze for five months. Pulmonary function tests demonstrated an obstructive pattern, and chest Xray showed fine micronodular opacities predominantly involving the middle and lower zones of both lungs. Transbronchial lung biopsy revealed the diagnosis. She responded well to inhaled steroid therapy. A systematic review of literature was performed and identified 73 cases of pulmonary alveolar microlithiasis reported from India. The mean (SD) age of the patients was 28.8 (14.9) years, with an almost equal male:female ratio. Many patients were asymptomatic at presentation. Breathlessness and cough were the most common symptoms, and the disease progressed into respiratory failure associated with cor pulmonale. About one-third of the cases were initially misdiagnosed and treated as pulmonary tuberculosis. Extra-pulmonary manifestations and comorbidities were also evident in our series. This systematic review helps to determine epidemiological and clinical characteristics of pulmonary alveolar microlithiasis. Further research is needed to elucidate the etiopathogenesis, diagnosis, and therapeutic options, which are beneficial in developing and identifying cost-effective treatment for pulmonary alveolar microlithiasis.

Microlithiasis of Seminal Vesicles and Severe Oligoasthenospermia in Pulmonary Alveolar Microlithiasis (PAM): Report of An Unusual Sporadic Case

Pulmonary alveolar microlithiasis (PAM) is classified as an elective dysmetabolic thesaurotic pneumoalveolitis and characterized by the presence within the alveoli of the lungs of myriad of tiny calculi. The classic presentation of the chest radiography is unmistakable with multiple small "sand-like" opacities diffusely involving both lung fields. We present a case of male infertility for hypoposia and severe oligoasthenospermia in a young patient with recurrent haematuria and small calcifications in the seminal vesicles similar to pulmonary microliths. PAM was diagnosed on routine chest radiography, com- puter tomography (CT), transbronchial biopsy and bronchoalveolar lavage (BAL).

Extensive pulmonary alveolar microlithiasis

Pulmonary alveolar microlithiasis is a rare pulmonary disorder that is caused by abnormal sodium-dependent phosphate co-transporter from the mutation of SLC34A2 gene, leading to accumulation of microliths in the alveoli. We report the extensive pulmonary alveolar microlithiasis in an elderly woman who presented with progressive dyspnea for 2 months. Chest radiograph revealed diffuse pulmonary calcification. Tissue histopathology from open lung biopsy demonstrated widespread intra-alveolar laminated calcium deposits compatible with pulmonary alveolar microlithiasis.

First presentation of a case of pulmonary alveolar microlithiasis with spontaneous pneumothorax

Pulmonary Alveolar Microlithiasis (PAM) is a rare disease of unknown origin. It is characterized by the presence of small calculi within the alveolar spaces, and has various clinical manifestations. Some patients may be asymptomatic for a long period of time with subsequent occurrence of dyspnea, dry cough, chest pain, and eventually, respiratory failure. Recurrent spontaneous pneumothorax episodes are a late complication of the disease. We report the case of an alveolar microlithiasis episode in a 42-year-old male, admitted to Tohid Hospital, Iran, whose first clinical presentation was symptoms of pneumothorax. He was admitted with sudden onset dyspnea and right-sided pleuretic chest pain. Following treatment of pneumothorax after chest tube placement, the pulmonary function revealed normal indices, and chest radiograph demonstrated diffuse confluence of dense micronodular infiltrate. High-resolution computerized tomography scan showed diffuse ground glass attenuation and calcifications along the interlobular septa and subpleural regions. Transbronchial lung biopsy confirmed the diagnosis of PAM.

Lung transplantation in an intensive care patient with pulmonary alveolar microlithiasis - a case report

INTRODUCTION

Pulmonary alveolar microlithiasis (PAM) is an autosomal recessive disease characterized by the deposition of phosphate and calcium in the alveoli. The disease progresses asymptomatically until later stages. When it becomes symptomatic, lung transplantations performed before the onset of right heart failure may improve life expectancy and quality. Here we present a case report concerning the very first Turkish PAM patient to have undergone lung transplantation surgery. Patient information: A 52 year-old female, Caucasian patient, already diagnosed with PAM in infancy, was admitted to the intensive care unit, diagnosed with pneumonia and hospitalized for 20 days. We decided to refer the patient to a specialized center for lung transplantation. Bilateral lung transplantation was performed in Vienna 14 months later and no recurrence was observed during the first postoperative year.

CONCLUSION

Bilateral lung transplantation may improve both the life expectancy and the quality of life of PAM diagnosed patients with severe respiratory failure who do not suffer from right heart failure. The risk of recurrence should not be considered as a justifying reason to avoid transplantation as a treatment method.

A silent storm

Pulmonary alveolar microlithiasis is a rare, inherited pulmonary disorder affecting young adults. Diagnosis and monitoring is important as it may progress to pulmonary fibrosis and respiratory failure. No effective treatment has been found to date.

Pulmonary alveolar microlithiasis with concurrent pleural mesothelioma in a dog

Pulmonary alveolar microlithiasis (PAM) is a rare pulmonary disorder characterized by the accumulation of calcium phosphate microliths within the alveoli, with only a few cases described in animals. A 10-year-old female Bulldog was euthanized due to history of dyspnea and recurrent pleural and pericardial effusions. At necropsy, numerous multifocal to coalescent protruding nodules of 1-5 mm in diameter were scattered throughout the thoracic serosal surfaces. Moreover, lungs showed a diffuse pale gray color and had a generalized fine grainy consistency. Histological investigations revealed abundant intra-alveolar laminated microliths that stained positive with periodic acid-Schiff and von Kossa stains. The pulmonary interstitium showed multifocal, mild to moderate thickening, due to collagen deposition and mild hyperplasia of type 2 pneumocytes. The pulmonary lesion was not associated with any inflammatory response, and mineral deposition was not observed in any other organ or tissue. In addition, pulmonary, pericardial, and pleural surfaces were extensively infiltrated by an epithelioid mesothelioma. Immunohistochemical staining revealed neoplastic cells that strongly coexpressed vimentin and cytokeratin, supporting the diagnosis of mesothelioma. An overview of PAM, including pathogenesis and histological characteristics, are discussed in relation to the concurrent pleural mesothelioma. The potential cause and effect relationship between the 2 conditions could neither be established nor ruled out.

Pulmonary alveolar microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a rare, chronic lung disease with bilateral intra-alveolar calcium and phosphate deposition throughout the lung parenchyma with predominance to lower and midzone. Although, etiology and pathogenesis of PAM is not fully understood, the mutation in SLC34A2 gene that encodes a sodium-phosphate co-transporter in alveolar type II cells resulting in the accumulation and forming of microliths rich in calcium phosphate (due to impaired clearance) are considered to be the cause of the disease. Chest radiograph and high-resolution CT of thorax are nearly pathognomonic for diagnosing PAM. HRCT demonstrates diffuse micronodules showing slight perilobular predominance resulting in calcification of interlobular septa. Patients with PAM are asymptomatic till development of hypoxemia and cor-pulmonale. No therapy has been proven to be beneficial except lung transplantation.

Pulmonary alveolar microlithiasis in an alpaca (Vicugna pacos)

Pulmonary alveolar microlithiasis (PAM) is a rare, familial disease of unknown aetiology characterised by intra-alveolar formation and accumulation of microliths. Multiple formalin-fixed tissues were submitted from a 5-month-old female alpaca that died suddenly without significant clinical signs. No gross abnormalities were observed on postmortem examination. Histological findings included PAM and severe centrilobular hepatic necrosis. Although the hepatic lesion was the likely cause of death, PAM was an incidental finding that has not been reported previously in alpacas. An overview of PAM, including pathogenesis and histopathological characteristics, are discussed in relation to the concurrent hepatic disease in the present case.

Pulmonary alveolar microlithiasis with low fluorodeoxyglucose accumulation in PET/computed tomography

Pulmonary alveolar microlithiasis (PAM) is an uncommon lung disease characterized by accumulation of intraalveolar calcifications. The disease can be diagnosed based on the radiological findings. We present a 27-year-old women with five-year history of shortness of breath. She was diagnosed with PAM due to the presence of the characteristic chest X-ray and thorax computed tomography (CT) findings. We performed ¹⁸F-fluorodeoxyglucose (FDG)-PET/CT imaging in order to detect any evidence of inflamation in the lung before deciding an anti-inflammatory treatment. The lung regions with dense calcifications revealed low FDG uptakes (SUVmax: 2.7) and the lung regions without calcifications showed lower FDG uptakes. No further treatment modality was planned besides inhaler salbutamol. Herein, we discuss this rare entity with literature search.

Pulmonary alveolar microlithiasis: a case report and review of the literature

A 12-year-old girl of Turkish descent was referred 6 weeks after an influenza A infection because of persistent chest X-ray abnormalities compatible with interstitial lung disease. The clinically suspected diagnosis of pulmonary alveolar microlithiasis (PAM) supported by pathognomonic radiological abnormalities was confirmed by genetic analysis. The clinical presentation of PAM is illustrated by a case and review of the current literature on this subject: you only see what you know.

Genetic interstitial lung disease

The interstitial lung diseases (ILDs), or diffuse parenchymal lung diseases, are a heterogeneous collection of more than 100 different pulmonary disorders that affect the tissue and spaces surrounding the alveoli. Patients affected by ILD usually present with shortness of breath or cough; for many, there is evidence of pulmonary restriction, decreased diffusion capacity, and radiographic appearance of alveolar and/or reticulonodular infiltrates. This article reviews the inherited ILDs, with a focus on the diseases that may be seen by pulmonologists caring for adult patients. The authors conclude by briefly discussing the utility of genetic testing in this population.

A case of pulmonary alveolar microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a rare disease with unknown etiology and pathogenesis. It is characterized by diffuse, innumerable, and minute calculi, called microlithiasis in the alveoli. More than half of reported cases are asymptomatic at the time of diagnosis. We describe the first case of PAM in Korea. A 19-yr-old man without respiratory symptoms presented with interstitial thickening on the chest radiograph. His chest high resolution CT scan showed diffusely scattered, ill defined tiny micronodules and interstitial thickening. Open lung biopsy confirmed the diagnosis of PAM. He was followed up for 6 months without treatment, and no progression was noticed.

Pulmonary alveolar microlithiasis with calcified pleural plaques

Pulmonary alveolar microlithiasis (PAM) is a rare disease. Herein we report a case of pulmonary alveolar microlithiasis who was suspected to have the disease on chest X-ray and was confirmed on high resolution CT and transbronchial lung biopsy. These investigations showed characteristic features of pulmonary alveolar microlithiasis with diffuse interstitial pulmonary fibrosis.

Long-term results of disodium etidronate treatment in pulmonary alveolar microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a rare disease with alveolar microliths mainly composed of calcium phosphate. The gene responsible for the disease is SLC34A2, which encodes a type-IIb sodium phosphate cotransporter, has been described recently. Treatment of this disease is not clearly defined. Disodium etidronate is a member of bisphonates and it has been administered in these patients due to its inhibitory effect on the precipitation of hydroxyapatite microcrystals. Here, clinical and radiological improvement of two patients with PAM who were treated with disodium etidronate for 9 and 11 years, respectively, are presented. The pathogenetic mechanism of this treatment on the genetic basis of disease is discussed.

Mutation analysis and serum FGF23 level in a patient with pulmonary alveolar microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a rare, hereditary disorder characterized by ectopic formation of calcium-phosphate microliths in the alveolar space. PAM has been reported to arise from inactivating mutations in SLC34A2, encoding a sodium-dependent phosphate co-transporter essential for phosphate transport in the lungs and small intestine. Serum levels of the phosphaturic hormone fibroblast growth factor-23 (FGF23) in PAM have not been determined. Our objectives were to investigate the genetic etiology and circulating level of FGF23 in a 50-year-old male with clinical characteristics of PAM and extra-pulmonary calcifications. The SLC34A2 and FGF23 genes were sequenced for mutations and serum FGF23 analyzed by ELISA. We found no disease-causing mutations or single nucleotide polymorphisms in the genes investigated. Importantly, repeated measurements revealed undetectable or markedly low serum FGF23 (<3-11 RU/ml). Surprisingly, in the face of low serum FGF23, 1,25-dihydroxy vitamin D₃ level was low-normal and parathyroid hormone mildly elevated. Total 24-h urinary excretion of phosphate and calcium were low, as was fractional urinary excretion of calcium. In contrast, fractional excretion of phosphate was above normal, likely due to elevated PTH. Collectively, PAM may be a polygenic disorder that arises from mutations other than in SLC34A2. The low FGF23 level in our PAM patient supports an intestinal-bone axis, leading to decreased FGF23 expression when intestinal phosphate absorption is compromised.

A frame-shift mutation in the SLC34A2 gene in three patients with pulmonary alveolar microlithiasis in an inbred family

Pulmonary alveolar microlithiasis (PAM) is a rare disease characterized by the presence of small calculi in the alveolar space. The SLC34A2 is thought to be responsible for the disease. We encountered three siblings of an inbred family who have PAM. We examined the family of the proband who was admitted with dyspnea on exertion and cough, and eventually was diagnosed with PAM. Genetic analysis revealed that both parents (a consanguineous marriage) of the proband were carriers with heterozygous mutation of SLC34A2 gene, and three of their children were diagnosed with PAM with homozygous mutation in the SLC34A2 gene. These findings suggest that impaired activity of the SLC34A2 gene may be responsible for familial PAM.

Pulmonary alveolar microlithiasis in a textile worker

Pulmonary alveolar microlithiasis is a rare lung disease characterized by small calculi, called calsispheritis, in the alveoli. The disease usually presents at age 20 to 30 years and is mostly diagnosed incidentally or detected on routine pulmonary roentgenograms. The radiologic findings are pathognomonic for the disease. Pulmonary alveolar microlithiasis most frequently appears in Turkey, followed by Italy. We present the case of a 29-year-old female textile worker found to have widespread micronodules after a routine pulmonary roentgenogram.

[Alveolar microlithiasis with severe interstitial fibrosis leading to lung transplantation]

Pulmonary alveolar microlithiasis is a rare disease, characterized by extensive phosphocalcic concretions within the alveolar spaces. Pulmonary alveolar microlithiasis is usually asymptomatic and is incidentally found because radiologic findings are characteristic. In about half of the cases, it is an autosomal recessive disorder due to mutations in the SLC34A2 gene. Pulmonary alveolar microlithiasis can easily be diagnosed by bronchioloalveolar lavage or transbronchial biopsy. The clinical course is usually stable during several years and lung transplantation is the only effective treatment when a respiratory failure occurs. A 49-year-old woman was referred with a restrictive respiratory failure due to a pulmonary alveolar microlithiasis incidentally discovered on a chest radiography when she was 11 and was confirmed by surgical lung biopsy. She was asymptomatic until she was 43 when she presented a progressive dyspnea leading to continuous oxygen administration 4 years later. Laboratory findings only showed a polyglobulia related to hypoxemia. Chest radiography and computed tomography chest scan revealed a bilateral symmetric micronodular pattern. She underwent a lung transplantation when she was 49. Pathological examination confirmed the diagnosis of diffuse pulmonary alveolar microlithiasis with interstitial fibrosis. The patient died 3 months after surgery in an infectious context.

Pulmonary alveolar microlithiasis with cor pulmonale: an autopsy case demonstrating a marked decrease in pulmonary vascular beds

Pulmonary alveolar microlithiasis (PAM) is a very rare autosomal recessive disorder in which microliths are formed in the alveolar space. PAM is infrequently complicated by pulmonary hypertension, the cause of which is unclear. The author in this paper found that the pulmonary hypertension was caused by a marked decrease in pulmonary vascular beds. Here, an autopsy case of PAM with a marked cor pulmonale is reported. A 14-year-old woman was found to have an abnormal pulmonary shadow, but the cause was unclear. At 24 years, she was diagnosed with a diffuse pulmonary abnormal shadow. At 42 years, she was diagnosed with PAM by imaging techniques. Her condition gradually worsened and she had to be treated with oxygen. She died of respiratory failure at 54 years. An autopsy revealed severe PAM and marked cor pulmonale. The heart weighed 360 g and right ventricular thickness was 10 mm (normal, 2-3 mm). Microscopically, the alveolar space was diffusely filled with microliths, and heart failure cells were recognized. Bone formations were scattered. The alveolar walls showed fibrous thickening, and pulmonary arteries showed atherosclerosis. The right ventricle showed marked cardiac hypertrophy. Chronic severe liver congestion was noted. A morphometric analysis using CD34-stained specimens showed a marked decrease (one tenth) in pulmonary capillary beds (capillary number: 8.6 +/- 3.1 per image), compared with normal lungs obtained from two other autopsies (85.3 +/- 9.4 and 96.2 +/- 10,3). It was concluded that the cor pulmonale and pulmonary hypertension in the present case were caused by the marked decrease of the pulmonary arterial vascular beds. More research is required regarding the etiology and treatment of PAM.