How I diagnose and treat organizing pneumonia in hematopoietic cell transplant recipients.

ABSTRACT: Organizing pneumonia (OP) is a known noninfectious pulmonary complication following allogeneic hematopoietic cell transplant (HCT) and represents a significant risk factor for nonrelapse mortality in HCT recipients. Unlike bronchiolitis obliterans syndrome, it is not universally acknowledged as a distinctive pulmonary manifestation of chronic graft-versus-host disease (cGVHD) and, therefore, its diagnostic criteria and management approach are lacking. Given its shared similar clinical features and radiological and histologic findings to OP in the non-HCT population, the diagnostic approach and treatment strategy for OP in HCT recipients is largely adapted from the non-HCT population. In this article, we aim to enhance the understanding of OP within the context of cGVHD following HCT and distinguish its clinical features and treatment strategy from non-HCT counterparts, thereby reinforcing its recognition as a pulmonary manifestation of graft-versus-host disease. We will propose the diagnostic criteria and outline our approach in diagnosis and treatment strategy, highlighting the potential challenges that may arise in each process. Finally, we will discuss knowledge gaps in this field and identify the area of need for future research.

A Case of Organizing Pneumonia Resembling Lung Cancer.

BACKGROUND: Organizing pneumonia (OP) is a pathologic diagnosis with clinical and imaging manifestations that often resemble other diseases, such as infections and cancers, which can lead to delays in diagnosis and inappropriate management of the underlying disease. In this article, we present a case of organized pneumonia that resembles lung cancer. METHODS: We report a case of initial suspicion of pulmonary malignancy, treated with anti-inflammatory medication and then reviewed with CT suggesting no improvement, and finally confirmed to be OP by pathological biopsy taken via transbronchoscopy. A joint literature analysis was performed to raise clinicians' awareness of the diagnosis and treatment of OP. RESULTS: Initially, because of the atypical auxiliary findings, we thought that the disease turned out to be a lung tumor, which was eventually confirmed as OP by pathological diagnosis. CONCLUSIONS: The diagnosis and treatment of OP requires a combination of clinical information and radiological expertise, as well as biopsy to obtain histopathological evidence. That is, clinical-imaging-pathological tripartite cooperation and comprehensive analysis.

Organizing Pneumonia due to Secondary Invasive Pulmonary Mycosis and Cytomegalovirus Infection in a Patient with Lymphoma.

BACKGROUND: Reactivation of cytomegalovirus is more common in lymphoma patients undergoing hematopoietic stem cell transplantation, but reactivation of cytomegalovirus due to chemotherapy for lymphoma has rarely been reported. We report a case of a lymphoma patient with secondary pulmonary fungal infection and cytomegalovirus infection after chemotherapy, which ultimately led to organizing pneumonia. METHODS: Percutaneous lung biopsy, Next Generation Sequencing (NGS). RESULTS: NGS examination suggestive of cytomegalovirus infection, percutaneous lung biopsy suggests the presence of organizing pneumonia. The patient was discharged after a combination of antifungal and antiviral treatment with posaconazole, ganciclovir, and anti-inflammatory treatment with methylprednisolone. CONCLUSIONS: In patients with lymphoma, one should be alert for fungal and viral infections of the lungs when lung related clinical manifestations occur. Patients with persistent unrelieved symptoms after treatment should undergo lung biopsy or bronchoscopy to obtain pathologic tissue for definitive diagnosis.

Organizing pneumonia associated with Richter transformation in chronic lymphocytic leukemia: a case report and review of the literature.

Organizing pneumonia (OP) is defined histologically by the presence of granulation tissue within alveolar ducts and alveoli. Recently, several lymphoid neoplasms have been implicated as a risk factor for OP, however, OP as a primary manifestation of malignancy transformation has not been widely reported in the literature. Here, we report a case of a patient with a history of chronic lymphocytic leukemia (CLL) who presented with weight loss, low-grade fever, lymphadenopathy, and bilateral pulmonary infiltrates revealed in imaging studies. Video-assisted thoracoscopic lung biopsy showed CLL cells within the pulmonary vessels and areas of OP in the lung parenchyma. Subsequent lymph nodes biopsies were consistent with CLL transformation to diffuse large B-cell lymphoma (DLBCL). To our knowledge, this is the first reported case of OP associated with CLL transformation into DLBCL. This case suggests that OP could represent a form of immunological reaction to ongoing Richter transformation.

Dual Antiviral Therapy for Persistent Coronavirus Disease 2019 and Associated Organizing Pneumonia in an Immunocompromised Host.

The management of patients with prolonged viral shedding and coronavirus disease 2019 symptoms remains unclear. Combining antivirals, as practiced in other infections, is theoretically advantageous. We present a case of persistent, symptomatic severe acute respiratory syndrome coronavirus 2 infection and associated organizing pneumonia that was successfully treated with an extended course of combination antiviral therapy.

Resolution of an insidious and migratory Mycobacterium tuberculosis-associated secondary organizing pneumonia: a case report and literature review.

BACKGROUND: Organizing pneumonia (OP) is a rare interstitial lung disease. Secondary organizing pneumonia (SOP) caused by Mycobacterium tuberculosis (MTB) is extremely rare. Migratory MTB-associated SOP is more deceptive and dangerous. When insidious tuberculosis (TB) is not recognized, SOP would be misdiagnosed as cryptogenic organizing pneumonia (COP). Use of steroid hormone alone leads to the progression of TB foci or even death. Clues of distinguishing atypical TB at the background of OP is urgently needed. CASE PRESENTATION: A 56-year-old female patient was hospitalized into the local hospital because of cough and expectoration for more than half a month. Her medical history and family history showed no relation to TB or other lung diseases. Community-acquired pneumonia was diagnosed and anti-infection therapy was initialized but invalid. The patient suffered from continuous weigh loss. More puzzling, the lesions were migratory based on the chest computed tomography (CT) images. The patient was then transferred to our hospital. The immunological indexes of infection in blood and pathogenic tests in sputum and the bronchoalveolar lavage fluid were negative. The percutaneous lung puncture biopsy and pathological observation confirmed OP, but without granulomatous lesions. Additionally, pathogen detection of the punctured lung tissues by metagenomics next generation sequencing test (mNGS) were all negative. COP was highly suspected. Fortunately, the targeted next-generation sequencing (tNGS) detected MTB in the punctured lung tissues and MTB-associated SOP was definitely diagnosed. The combined therapy of anti-TB and prednisone was administrated. After treatment for 10 days, the partial lesions were significantly resorbed and the patient was discharged. In the follow-up of half a year, the patient was healthy. CONCLUSIONS: It is difficult to distinguish SOP from COP in clinical practice. Diagnosis of COP must be very cautious. Transient small nodules and cavities in the early lung image are a clue to consider TB, even though all pathogen tests are negative. tNGS is also a powerful tool to detect pathogen, ensuring prompt diagnosis of TB-related SOP. For clinicians in TB high burden countries, we encourage them to keep TB in mind before making a final diagnosis of COP.

Organizing Pneumonia with NGS False-Positive Imaging Resembling Tuberculosis: a Case Report.

BACKGROUND: Organizing pneumonia (OP) is a pathologic concept characterized by the formation of granulation tissue from fibroblasts, myofibroblasts, collagen, and fibrotic exudate in the respiratory fine bronchi, alveolar ducts, and alveoli. The clinical imaging of mechanized pneumonia is variable, and histopathological examination is required to clarify the nature of the lesion when imaging is atypical. We report a case of OP with imaging resem-blance to pulmonary tuberculosis and false-positive next-generation sequencing (NGS), which was first misdiag-nosed as pulmonary tuberculosis. METHODS: Appropriate laboratory tests, alveolar lavage fluid NGS, chest CT, bronchoscopy, percutaneous lung puncture, pathology. RESULTS: Chest CT showed a nodular high-density shadow in the lower lobe of the right lung. According to the chest CT, bronchoalveolar lavage was performed in the dorsal segment of the right lower lobe of the lung. NGS of lavage fluid: the sequence number of Moraxella osseae was 1,423; the sequence number of Prevotella melanogaster was 1,129. Based on lung histopathology, fibrous emboli and necrotic material were seen in the alveolar lumen, and the final diagnosis of the OP was confirmed. CONCLUSIONS: It should be noted that physicians should not blindly believe the NGS result report. When the diagnosis is not clear and anti-infection treatment is ineffective, lung tissue should be obtained promptly for pathological examination to obtain pathological evidence to differentiate from misdiagnosed diseases.

Organizing Pneumonia Secondary to Infection with Coxiella Burnetii: a Case Report.

BACKGROUND: Organizing pneumonia is a non-specific inflammatory response to various types of damage to the lungs. It is usually considered bacterial pneumonia that has not been absorbed for more than 4 weeks, accompanied by granulomas and fibrosis. Lung lesions in patients with organizing pneumonia are usually irreversible and the prognosis is relatively poor. Coxiella burnetii can cause Q fever. Acute Q fever usually presents as a self-limiting febrile illness with a good prognosis, but there are few cases of coexisting organizing pneumonia. We report a case of organizing pneumonia secondary to Coxiella burnetii infection. METHODS: Percutaneous lung biopsy, Next-generation sequencing (NGS). RESULTS: Percutaneous lung biopsy showed the existence of organizing pneumonia, and external examination of NGS showed the existence of Coxiella burnetii infection. After symptomatic treatment with azithromycin and glucocorticoids, the patient improved and was discharged from the hospital. CONCLUSIONS: For lesions with obvious heterogeneous enhancement on chest CT imaging, percutaneous lung biopsy or bronchoscopy should be performed promptly to obtain pathological tissue, and NGS should be used for definite diagnosis if necessary.

A case of drug-induced organizing pneumonia caused by amikacin liposome inhalation suspension.

Inhaled liposomal antimicrobials are known to cause hypersensitivity pneumonitis. Amikacin liposome inhalation suspension (ALIS) is a promising novel antimicrobial agent against refractory Mycobacterium avium complex infections. The frequency of drug-induced lung injury caused by ALIS is relatively high. To date, no reports of ALIS-induced organizing pneumonia diagnosed by bronchoscopy are available. We report a case of a 74-year-old female patient presenting with non-tuberculous mycobacterial pulmonary disease (NTM-PD). She was treated with ALIS for refractory NTM-PD. Fifty-nine days after starting ALIS, the patient developed a cough, and her chest radiographs indicated deterioration. She was diagnosed with organizing pneumonia based on pathological findings of the lung tissues obtained by bronchoscopy. After switching from ALIS to amikacin infusion, her organizing pneumonia improved. It is difficult to distinguish between organizing pneumonia and an exacerbation of NTM-PD based on chest radiography alone. Therefore, it is essential to perform an active bronchoscopy for diagnosis.

The relationship between organising pneumonia and invasive mould disease in patients with haematologic malignancy.

BACKGROUND: Organising pneumonia (OP) is reported in patients with haematologic malignancy suspected of having invasive mould disease, yet little is known about this relationship. OBJECTIVE: To investigate molecular evidence of invasive mould pneumonia in paraffin-embedded lung tissues from histologically diagnosed OP patients with suspected invasive mould pneumonia. PATIENTS/METHODS: Patients with haematologic malignancy suspected to have invasive pulmonary mould disease who underwent lung biopsy at a tertiary hospital, Seoul, South Korea, between 2008 and 2020, were retrospectively reviewed. To find molecular evidence of fungal infection, PCR assay was used to detect Aspergillus- and Mucorales-specific DNA within OP lung tissue sections. RESULTS: Forty-seven patients with suspected invasive mould pneumonia underwent lung biopsy and 15 (32%) were histologically diagnosed as OP without any evidence of fungal hyphae. Of these 15 patients, 3 (20%) received allogenic haematopoietic stem cell transplantation prior to developing OP. Before biopsy, 2 and 13 patients had probably and possible invasive mould disease, respectively. The median antifungal treatment length was 81 [8-114] days, and the median steroid treatment dosage was 0.35 mg/kg/day for 36 days (methylprednisolone equivalent doses), respectively. After biopsy, three patients with possible invasive mould infection revealed probable invasive pulmonary aspergillosis. From the 15 paraffin-embedded lung tissues, 6 (40%) exhibited positive PCR assay results for detecting Aspergillus- and Mucorales-specific DNA. CONCLUSIONS: More than one third of OP cases in patients with suspected invasive mould pneumonia exhibited molecular evidence of invasive mould infection by fungus-specific PCR in lung tissues, likely associated with concurrent or prior fungal infection.

Pulmonary syphilis with a cicatricial variant of organizing pneumonia: a case report.

BACKGROUND: Syphilis is a chronic disease that progresses in the primary, secondary, latent, and tertiary stages. Pulmonary manifestations of syphilis are rare, and their histological features have not been well-described. CASE PRESENTATION: A 78-year-old man was referred to our hospital because of a solitary nodular shadow in the right middle lung field on a chest radiograph. Five years prior, a rash appeared on both legs. He was tested for syphilis at a public health center, and the non-treponemal test result was negative. When he was approximately 35 years old, he had unspecified sexual intercourse. Chest computed tomography showed a 13-mm nodule with a cavity in S6 of the right lower lobe of the lung. Robot-assisted resection of the right lower lobe was performed because of suspected localized right lower lobe lung cancer. A cicatricial variant of organizing pneumonia (CiOP) was observed, and immunohistochemistry identified Treponema pallidum inside the macrophages in the nodule cavity. The rapid plasma regain (RPR) value was negative, and the Treponema pallidum hemagglutination assay was positive. The patient was diagnosed as having secondary syphilis with pulmonary involvement. Insidious progression of secondary syphilis may result in CiOP and a negative RPR test result. CONCLUSIONS: We report the first case of pulmonary syphilis with a histological pattern of CiOP. It may be asymptomatic and difficult to diagnose because the RPR test may be negative for a long period of time. When either non-treponemal or treponemal test results are positive, the possibility of pulmonary syphilis should be considered along with appropriate medical treatment.

Properties of Pleural Mesothelial Cells in Idiopathic Pulmonary Fibrosis and Cryptogenic Organizing Pneumonia.

BACKGROUND: Profibrotic properties of pleural mesothelial cells may play an important role in the fibrosis activity in idiopathic pulmonary fibrosis (IPF). The purpose of this study was to compare the expression of pleural mesothelial cell markers in IPF and cryptogenic organizing pneumonia (COP), with an assumption that increased expression implies increase in fibrosis. METHODS: Twenty IPF lung samples were stained by immunohistochemistry for the pleural mesothelial cell markers: leucine rich repeat neuronal 4 (LRRN4), uroplakin 3B, CC-chemokine ligand 18, and laminin-5. Nine COP lung samples were used as controls. A semi-quantitative analysis was performed to compare markers expression in IPF and COP. RESULTS: LRRN4 expression was found in epithelial lining cells along the honeycombing and fibroblastic foci in IPF, but not in the fibrotic interstitial lesion and airspace filling fibrous tufts in COP. We found a significant decrease in baseline forced vital capacity when LRRN4 expression was increased in honeycombing epithelial cells and fibroblastic foci. CONCLUSION: LRRN4 expression patterns in IPF are distinct from those in COP. Our findings suggest that mesothelial cell profibrotic property may be an important player in IPF pathogenesis and may be a clue in the irreversibility of fibrosis in IPF.

Bronchiolitis obliterans organising pneumonia secondary to tacrolimus toxicity in a pediatric cardiac transplant recipient.

BACKGROUND: Bronchiolitis obliterans organising pneumonia is a rare complication associated with calcineurin inhibitors and mammalian target of rapamycin inhibitors. While bronchiolitis obliterans organising pneumonia in adult transplant patients has been reported, it has not been well described in pediatric transplant patients. CASE DESCRIPTION: We present a case of a 19-month-old male patient with dilated cardiomyopathy who underwent orthotropic heart transplantation at 14 months of life for heart failure refractory to medical therapy. Approximately 4 months post-transplant, he presented with diarrhea and vomiting with acute kidney injury secondary to dehydration. His tacrolimus level on admission and first week of hospitalisation was within target range of 10-12 ng/ml. He was diagnosed with esophagitis and prescribed proton pump inhibitors. Our patient subsequently developed significant respiratory distress with initial chest radiograph showing right lower lobe opacities. Repeat tacrolimus at the time of worsening respiratory status was 84.2 ng/dL and his tacrolimus was held. He required intubation due to significant hypoxia with progression of lung to disease and development of diffuse bilateral opacities consistent with acute respiratory distress syndrome. Despite initiation of steroids and aggressive ventilator management, he continued to be hypoxic on maximal respiratory support. After 28 days post admission, support was withdrawn. On autopsy, his lung biopsy findings were consistent with bronchiolitis obliterans organising pneumonia. CONCLUSION: Life-threatening bronchiolitis obliterans organising pneumonia can be seen in pediatric transplant patients on tacrolimus or when transitioning from tacrolimus to sirolimus, highlighting the need for close monitoring of heart transplant patients on immunosuppressive medications presenting with hypoxia.

Organizing Pneumonia in A Patient Double-Positive for ANCA and Anti-GBM Antibodies: A Case Report.

Both anti-glomerular basement membrane (GBM) disease and the anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) are common causes of pulmonary-renal syndrome. Organizing pneumonia (OP), a special pattern of interstitial lung disease, is extremely rare either in AAV or anti-GBM disease. We report an old woman presented with OP on a background of co-presentation with both ANCA and anti-GBM antibodies.

Clinical and radiological outcomes of SARS-CoV-2 related organising pneumonia in COVID-19 survivors.

INTRODUCTION: COVID-19 patients frequently demonstrate radiological organising pneumonia (OP) pattern. The longterm outcome and treatment options for this group of patients remain uncertain. We aim to describe the clinical and radiological outcomes of patients with COVID-19-related OP and identify possible clinical factors associated with inferior radiological outcome. MATERIALS AND METHODS: Post-COVID-19 clinic attendees, consisting of post-COVID-19 patients discharged from major hospitals in the state of Selangor during the third pandemic wave of COVID-19 in Malaysia, were enrolled in this retrospective study for 6 months. Physician-scored Modified Medical Research Council (mMRC), patient self-reported quality of life (EQ-VAS) score and follow-up CT scan were evaluated. RESULTS: Our cohort comprised 131 patients, with a median age of 52 (IQR 39-60) years and median BMI of 29.40 (IQR 25.59-34.72). Majority (72.5%) had co-morbidities, and 97.7% had severe disease requiring supplementary oxygen support during the acute COVID-19 episode. 56.5% required intensive care; among which one-third were invasively ventilated. Median equivalent dose of methylprednisolone prescribed was 2.60 (IQR 1.29-5.18) mg/kg during admission, while the median prednisolone dose upon discharge was 0.64 (IQR 0.51-0.78) mg/kg. It was tapered over a median of 8.0 (IQR 5.8-9.0) weeks. Upon follow-up at 11 (IQR 8-15) weeks, one-third of patients remained symptomatic, with cough, fatigue and dyspnoea being the most reported symptoms. mMRC and EQ-VAS scores improved significantly (p<0.001) during follow-up. Repeat CT scans were done in 59.5% of patients, with 94.8% of them demonstrating improvement. In fact, 51.7% had complete radiological resolution. Intensive care admission and mechanical ventilation are among the factors which were associated with poorer radiological outcomes, p<0.05. CONCLUSION: Approximately one-third of patients with SARSCoV- 2-related OP remained symptomatic at 3 months of follow-up. Majority demonstrated favourable radiological outcomes at 5-month reassessment, except those who required intensive care unit admission and mechanical ventilation.

[Myelodysplastic syndrome with der (1;7)(q10;p10) complicated with eosinophilia and organizing pneumonia].

The unbalanced translocation der (1;7)(q10;p10) is a characteristic cytogenetic abnormality observed in myelodysplastic syndrome (MDS). A 63-year-old man presented to our hospital with fever and lung disease. The chromosomal analysis of bone marrow cells showed 46, XY, +1, der (1;7)(q10;p10) in all four metaphases. The patient was diagnosed with MDS. Bronchoscope examination revealed organizing pneumonia. The patient's eosinophil count rose to 39% after 30 days. His fever and dyspnea worsened, and a skin rash (systemic erythema) appeared simultaneously. Therefore, the patient was commenced on azacitidine and corticosteroids. Although treatment with both drugs could control disease progression transiently, the WT-1 value and the percentage of myeloblasts in the patient's bone marrow increased. Therefore, the patient received hematopoietic stem cell transplantation from his haplo-identical donor daughter. Some reports have demonstrated that patients with MDS with der (1;7)(q10;p10) have better prognosis than those with other abnormalities, such as -7/7q-. However, reported cases with severe complications show very poor prognosis. MDS with der (1;7)(q10;p10) complicated by eosinophilia and organizing pneumonia have not been reported, and its prognosis is expected to be very poor. Our case suggests that such cases might quickly require hematopoietic stem cell transplantation before the disease worsens.

[Organizing Pneumonia with Difficult Differentiation from Lung Cancer:Report of a Case].

A 72-year-old woman underwent a close examination because of chest computed tomography (CT) scan revealed a nodule in the left lower lobe of the lung. Positron emission tomography( PET) showed strong accumulation of fluorodeoxyglucose (FDG) in the lesion. Since lung cancer was strongly suspected, video-assisted thoracoscopic lung biopsy was performed. The lesion was diagnosed as organizing pneumonia by pathology. PET is widely used to distinguish between benign and malignant lung nodules, but FDG accumulation can also be seen in benign diseases such as inflammatory lesions. Abnormal accumulation can also be seen in organizing pneumonia, but strong FDG accumulation such as in this case is relatively rare, and it was difficult to distinguish it from lung cancer.

[HUMIDIFIER LUNG WITH ORGANIZING PNEUMONIA DETECTED BY BRONCHOSCOPY: A CASE REPORT].

A 58-year-old man presented with dyspnea on exertion and diffuse ground-glass opacities with mosaicism on chest computed tomography in April 201X. A transbronchial lung biopsy revealed organizing pneumonia and lymphocytic infiltration, and steroids were administered. During steroid tapering, the shortness of breath and ground-glass opacities recurred, and a transbronchial lung re-biopsy revealed organizing pneumonia without a granuloma again. Based on the clinical history, imaging features, and amount of humidifier usage, hypersensitivity pneumonitis caused by a humidifier was suspected. The inhalation challenge test was considered positive, and the diagnosis was confirmed. There have been some reports of unidentified granuloma in patients with humidifier lungs. Therefore, this case suggests that humidifier lung should be considered as a possibility even if pathological examination does not reveal granulomas and inflammatory changes such as organizing pneumonia are the only findings.

A review of organizing pneumonia.

ABSTRACT: Organizing pneumonia is a clinical and pathological syndrome that describes a lung injury caused by an inflammatory reaction in the alveolar connective tissue. Classified as an interstitial lung disease, it can be secondary to infection, drug toxicity, connective tissue disorders, inhalation injuries (cocaine), organ transplant, or radiotherapy, and also can be idiopathic. Although organizing pneumonia is not a new phenomenon, it has been noted to be a complication of COVID-19, and should be considered in patients who have had COVID-19 and have atypical chest imaging, because treatment includes corticosteroids instead of antimicrobials.