FDG-PET/CT finding of high uptake in pulmonary alveolar microlithiasis

Pulmonary alveolar microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a fascinating rare lung disease that is associated with the accumulation of hydroxyapatite microliths within the lumen of the alveolar spaces. In most patients, PAM is discovered incidentally on radiographs performed for other purposes, and the typical disease course is characterised by slowly progressive respiratory insufficiency over decades. Recent genetic analyses that have revealed that the deficiency of the sodium-phosphate cotransporter NPT2B is the cause of PAM have enabled the development of powerful animal models that inform our approach to disease management and treatment. Here we review the epidemiology and molecular pathophysiology of PAM, as well as the diagnostic approach, clinical manifestations, radiographic and pathologic features, and clinical management of the disease. Although there are no proven treatments for PAM, progress in our understanding of disease pathogenesis is providing insights that suggest strategies for trials.

A review of the epidemiology and molecular pathophysiology of pulmonary alveolar microlithiasishttps://bit.ly/3lBgM7p

Pulmonary alveolar microlithiasis: no longer in the stone age

Pulmonary alveolar microlithiasis (PAM) is a rare parenchymal lung disease caused by variants in the SCL34A2 gene and characterised by the accumulation of intra-alveolar microliths. PAM has been reported in fewer than 1100 cases throughout the world. It is an autosomal recessive hereditary disease and often associated with consanguinity. Progress with respect to the genetic background and pathophysiology has resulted in an increased understanding of the disease in recent years. Until now, 30 genetic different SLC34A2 variants have been reported, which all are considered significant for disease development. There is no sex difference and the majority of cases are diagnosed at the age of 30–40 years. Many patients are asymptomatic and the diagnosis is made at random. When symptomatic, dyspnoea, cough, chest pain and fatigue are common complaints. The diagnosis of PAM can confidently be based on typical radiographic findings and genetic testing proving rare biallelic SCL34A2 gene variants. Bronchoalveolar lavage and histopathology may show microliths. There is no disease-specific treatment and management is supportive. Lung transplantation should be considered in advanced cases.

Pulmonary alveolar microlithiasis is a rare, autosomal recessive lung disease. Formation of alveolar microliths is caused by SCL34A2 variants. The prognosis is severe; respiratory failure is common. Lung transplantation is the only effective therapy.https://bit.ly/3dpkbRw

Pulmonary Alveolar Microlithiasis: a Case Report in King Hussein Medical Center (KHMC), Amman, Jordan

Introduction:

Pulmonary Alveolar Microlithiasis (PAM) is a rare disorder that can affect patients at any age, although it is more common to present in the third and fourth decades of life. Most patients are asymptomatic at the time of diagnosis. However, some may present with symptoms of dyspnea or cough. PAM can be sporadic, or it can be hereditary.

Aim:

To focus on the importance of using chest CT scans along with bone scintigraphy to aid in the diagnosis of PAM. The importance of screening all family members is also addressed.

Case report:

In our case, the patient was a 21-year-old male, coming for routine check-up to be recruited in the army. He was referred to our clinic after the examining doctor noticed that his chest X-Ray was not normal. Upon revising his chest X-ray, he was found to have bilateral fine reticular infiltrates. His physical examination was unremarkable. His spirometry and DLCO were normal. A high-resolution chest CT scan was done, and showed diffuse bilateral microcalcifications with bilateral interstitial and septal thickening. To confirm the diagnosis of PAM, a Technetium-99m methylene diphosphonate (Tc-99m MDP) whole body bone scintigraphy was done, and it showed diffusely increased radiotracer uptake in both lungs. His family members were screened for PAM. His father and sister, who were completely asymptomatic and with normal pulmonary function tests, were found to have PAM as well.

Conclusion:

The use of bone scintigraphy plays an integral role in diagnosing patients with radiological findings consistent with PAM, and it can diagnose PAM without the need for invasive procedures. Once diagnosed, screening of all family members for PAM should be done, even when they are asymptomatic, as more than one-third of the cases have a familial pattern.

[Alveolar microlithiasis: about a new case]

Alveolar microlithiasis (AM) is a rare disease, characterized by the accumulation of calcium concretions in the pulmonary alveolar lumen. We report a new case of AM suspected on chest X-ray and confirmed by chest CT scan, whose appearance was pathognomonic, and by transbronchial pulmonary biopsy. AM is often asymptomatic, contrasting with the importance of lesions on X-ray which are characteristics of this disease. The cause of this disease is unknown. However autosomal recessive inheritance with mutation in the SLC34A2 gene is suspected.

Diffuse pulmonary uptake of bone-seeking radiotracer in bone scintigraphy of a rare case of pulmonary alveolar microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a rare diffuse pulmonary disease representing microliths formed by deposition of calcium phosphonate in the alveolar airspaces. PAM is often diagnosed incidentally during chest X-ray imaging. Most of them are asymptomatic. We present a 39-year-old man referring for a bone scan due to a complaint of right leg pain. Bone scan showed diffuse uptake of bone-seeking radiotracer on both lung fields predominantly in basal regions. The bronchoalveolar lavage test confirmed the diagnosis of PAM.

Imaging calcific concretions of pulmonary alveolar microlithiasis with PET: insight into disease pathophysiology

A case of 18F-FDG PET in pulmonary alveolar microlithiasis with bilateral reticulonodular opacities in the middle and lower zones on routine chest roentgenogram and calcification in the peribronchovascular interstitium,peribronchovascular and subpleural intralobular septal regions, and visceral pleura on high-resolution chest CT is presented. 18F-fluoride PET demonstrated intense tracer uptake in the lower zone of both lungs corresponding to CT findings. Minimal FDG activity in areas of dense calcification suggests minimal or no inflammation. This could account for the absence of symptoms in most cases despite remarkable imaging findings.

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.