Adult exogenous lipoid pneumonia: A rare and underrecognized entity in cytology - A case series

Extrinsic lipoid pneumonia due to chronic polyethylene glycol consumption: A case report

Extrinsic lipoid pneumonia (ELP) results from the aspiration of lipid-containing substances. Tissue or cell histopathology after Oil-Red-O staining can confirm the diagnosis, which requires proper tissue handling and preparation during bronchoscopy. Here, we report a case of ELP in a quadriplegic patient with a long history of dysphagia and polyethylene glycol consumption. Computed tomography (CT) of the chest revealed multiple, progressively enlarging, fat-attenuated, nodular pulmonary lesions. Bronchoscopy with bronchoalveolar lavage (BAL) and a transbronchial forceps biopsy confirmed the diagnosis of lipoid pneumonia. We discuss the clinical, radiological, and pathological features of ELP and highlight the preparatory steps required for obtaining a successful diagnosis.

Oil Red O Staining of Pulmonary Macrophages in Bronchoalveolar Lavage Specimens Is Not Specific for Vaping-Associated Lung Injury

Objectives

Oil Red O (ORO) positivity in bronchoalveolar lavage (BAL) fluid macrophages in the setting of e-cigarette, or vaping, product use–associated acute lung injury (EVALI) has been frequently requested by clinicians based on rare reports and subsequent US Centers for Disease Control and Prevention guidelines. The aim of this study was to determine the specificity of ORO staining in BAL specimens with disease states other than EVALI.

Methods

Consecutive BAL specimens (October-December 2019) were stained with ORO. The lipid-laden macrophage index (LLMI) was calculated for each case.

Results

We studied BAL samples from 50 patients. Indications for BAL were surveillance bronchoscopy for lung transplantation (27/50), suspected infection (12/50), sarcoidosis/suspected sarcoidosis (3/50), nodules or ground-glass opacities (3/50), hemoptysis (2/50), asthma or eosinophilic pneumonia (2/50), and idiopathic pulmonary fibrosis (1/50). ORO staining was seen in BAL fluid macrophages in 45 of 50 cases (focal in 18, moderate in 23, diffuse in 4); LLMI ranged from 0 to 218. Using a threshold of LLMI of 85 or higher as positive, ORO was positive in 7 of 50 (14%) cases (range, 85-218).

Conclusions

ORO staining in BAL fluid macrophages is not specific for EVALI. Even when an LLMI of 85 or higher is used as a threshold for positivity, ORO positivity occurs in a significant subset of non–vaping-related cases.

A 66-Year-Old Man With Subacute Cough and Worsening Dyspnea Previously Diagnosed With COVID-19 Pneumonia

A 66-year-old man presented with subacute cough and worsening dyspnea. Labs were notable for moderate peripheral eosinophilia, and computed tomography (CT) scan demonstrated extensive crazy-paving throughout bilateral upper lung fields. Bronchoalveolar lavage (BAL) revealed macrophages with lipid-filled vacuoles and negative periodic acid-Schiff (PAS) stain. Further history obtained from the patient and family was notable for daily application of commercially available vapor rub to nares and intentional deep inhalation of nebulized fluids containing scented oils. The patient was diagnosed with exogenous lipoid pneumonia through an unusual route of lipid administration.

A 48-Year-Old Amateur Bodybuilder With History of Provoked DVT With Subacute Progressive Shortness of Breath

CASE PRESENTATION

A 48-year-old man presented with 6 months of progressive shortness of breath, intermittent exertional left-sided chest pain, and bilateral lower extremity edema. During the 2 days before admission, he experienced new onset confusion, fatigue, and malaise that prompted evaluation. He denied fever, chills, cough, or sputum production. He used anabolic steroids for 20 years as part of his bodybuilding hobby. Recently, he also began injecting mineral oil into his pectoral, bicep, and shoulder muscles for an improved muscular appearance. Additionally, he had a history of provoked DVT after traumatic fracture, schizophrenia, hypertension, and epilepsy. He was a former cigarette smoker with 2.5 pack-year history, having quit 10 years earlier. The patient's occupation was construction, installing aluminum gutters. He specifically denied exposures to sand-blasting, coal, beryllium, hard metals, silicone, and fine particles. He had no recent travel, sick contacts, or animal exposures.

Understanding potential mechanisms of harm: the drivers of electronic cigarette-induced changes in alveolar macrophages, neutrophils, and lung epithelial cells

Electronic (e-) cigarettes are growing in popularity despite uncertainties regarding their long-term health implications. The link between cigarette smoking and initiation of chronic lung disease took decades to unpick so in vitro studies mimicking e-cigarette exposure aim to detect early indicators of harm. In response to e-cigarette exposure, alveolar macrophages adopt a proinflammatory phenotype of increased secretion of proinflammatory cytokines, reduction in phagocytosis, and efferocytosis and reactive oxygen species generation. These effects are largely driven by free radical exposure, changes in PI3K/Akt signaling pathways, nicotine-induced reduction in phagocytosis receptors, and impaired lipid homeostasis leading to a foam-like lipid-laden phenotype. Neutrophils exhibit disrupted chemotaxis and transmigration to chemokines, reduced phagocytosis and bacterial killing, and an increase in protease secretion without corresponding antiproteases in response to e-cigarette exposure. This is driven by an altered ability to respond and to polarize toward chemoattractants, an activation of the p38 MAPK signaling pathway and inability to assemble NADPH oxidase. E-cigarettes induce lung epithelial cells to display decreased ciliary beat frequency and ion channel conductance as well as changes in chemokine secretion and surface protein expression. Changes in gene expression, mitochondrial function, and signaling pathways have been demonstrated in lung epithelial cells to explain these changes. Many functional outputs of alveolar macrophages, neutrophils, and lung epithelial cells have not been fully explored in the context of e-cigarette exposure and the underlying driving mechanisms are poorly understood. This review discusses current evidence surrounding the effects of e-cigarettes on alveolar macrophages, neutrophils, and lung epithelial cells with particular focus on the cellular mechanisms of change.

Shine like gold and sparkle like glitter: Three cases of lipoid pneumonia

Lipoid pneumonia (LP) is an unwonted, mostly asymptomatic entity which has no classical radiological appearance. It can be endogenous or exogenous depending upon the type of exposure or underlying milieu. It simulates a number of infective and malignant respiratory conditions and can go undiagnosed or delayed leading to morbidity and mortality. We put forward three cases that initially presented as classical pneumonia, but on further assessment and investigations were diagnosed to be LP. All the three cases manifested with symptoms of fever, productive cough and breathlessness. Chest Xray and CT scan were indicative of consolidation. Bronchoalveolar lavage (BAL) evinced lipid laden macrophages that stained positive with fat stains (Sudan IV and Oil Red O). Two cases were endogenous and one was exogenous type. LP, owing to its nonspecific clinical presentation and radiographic signs, needs a high index of suspicion, and a detailed clinical history for accurate diagnosis. Corroboration of lipid laden alveolar macrophages in BAL is the crux to the diagnosis. Hence, clinicians should be cognizant of this condition and rule out LP in cases of non-resolving pneumonia in an appropriate clinical context.

E-Cigarette or Vaping Product Use-Associated Lung Injury: A Review for Pathologists

CONTEXT.—

Vaping is the inhalation of heated aerosol from a small battery-powered device as a method to deliver nicotine or other substances. A recent outbreak of severe respiratory illness primarily in the United States has put a spotlight on vaping and its potential risks.

OBJECTIVE.—

To familiarize pathologists with vaping, the cytologic and histopathologic features of vaping-associated acute lung injury, and the role of pathology in this diagnosis.

DATA SOURCES.—

A targeted literature review was performed.

CONCLUSIONS.—

Most cases of vaping-associated lung injury have been linked to vaping products containing tetrahydrocannabinol or other cannabinoids. Lung biopsies show a spectrum of nonspecific acute lung injury patterns (organizing pneumonia, diffuse alveolar damage, acute fibrinous, and organizing pneumonia, or combinations of the above), accompanied by prominent, foamy macrophage accumulation. Injury is usually accentuated around small airways. Lipid-laden macrophages can be identified in bronchioloalveolar lavage fluid in most patients and these can be highlighted using lipid stains, such as oil red O, but the clinical utility of this finding remains unclear, as lipid-laden macrophages can be seen in a wide variety of processes and should not be relied upon to make the diagnosis. Classic histologic features of exogenous lipoid pneumonia have not been identified in tissue samples. Lightly pigmented macrophages, similar to those seen with traditional cigarette smoking, are present in some cases but are usually a minor feature. To date, no specific pathologic features for vaping-related injury have been identified, and it remains a diagnosis of exclusion that requires clinicopathologic correlation.

Dose-Dependent Pulmonary Toxicity of Aerosolized Vitamin E Acetate

Electronic-cigarette, or vaping, product use-associated lung injury (EVALI) is a syndrome of acute respiratory failure characterized by monocytic and neutrophilic alveolar inflammation. Epidemiological and clinical evidence suggests a role of vitamin E acetate (VEA) in the development of EVALI, yet it remains unclear whether VEA has direct pulmonary toxicity. To test the hypotheses that aerosolized VEA causes lung injury in mice and directly injures human alveolar epithelial cells, we exposed adult mice and primary human alveolar epithelial type II (AT II) cells to an aerosol of VEA generated by a device designed for vaping oils. Outcome measures in mice included lung edema, BAL analysis, histology, and inflammatory cytokines; in vitro outcomes included cell death, cytokine release, cellular uptake of VEA, and gene-expression analysis. Comparison exposures in both models included the popular nicotine-containing JUUL aerosol. We discovered that VEA caused dose-dependent increases in lung water and BAL protein compared with control and JUUL-exposed mice in association with increased BAL neutrophils, oil-laden macrophages, multinucleated giant cells, and inflammatory cytokines. VEA aerosol was also toxic to AT II cells, causing increased cell death and the release of monocyte and neutrophil chemokines. VEA was directly absorbed by AT II cells, resulting in the differential gene expression of several inflammatory biological pathways. Given the epidemiological and clinical characteristics of the EVALI outbreak, these results suggest that VEA plays an important causal role.

Vaping-Induced Lung Injury: A Case of Lipoid Pneumonia Associated with E-Cigarettes Containing Cannabis

Electronic cigarette, or vaping product use-associated lung injury (EVALI), is a group of lung disorders associated with vaping and e-cigarette products that has previously been categorized as a diagnosis of exclusion and best described as an exogenous lipoid pneumonia or chemical pneumonitis. Here, we describe the onset of an exogenous cause of lipoid pneumonia in an otherwise healthy patient using cannabis-containing electronic cigarettes. We explore similarities in the clinical case, define a common clinical presentation with progression of disease, characteristic radiographic findings along with pathological diagnosis and management.