A curious case of exploding cannonball

Introduction: Mycobacterium malmoense is a slow-growing, non-tuberculous mycobacterium which primarily causes pulmonary disease. M. malmoense is acquired through environmental exposure to contaminated soil or water in individuals with impaired cell immunity. M. malmoense infection may cause extrapulmonary manifestations including cervical adenitis, tenosynovitis, and disseminated disease. Our literature search revealed extremely few cases reported on M. malmoense causing cavitary lesions. We present a case of a patient with hemoptysis and worsening bilateral lung cavitary lesions where sputum culture isolated M. malmoense. Case presentation: A 58-year-old male with a past medical history of hypertension, 80-pack-year smoking history, polysubstance abuse with methamphetamine, cannabis, benzodiazepines, hepatitis C, COPD, and chronic cavitary lung lesions was admitted to the hospital secondary to hemoptysis. He had an initial episode of hemoptysis approximately one year ago which self-resolved after six days. He was scheduled to receive outpatient bronchoscopy for his chronic cavitary lesions though missed follow-up. Two days before the current admission, the patient had worsening cough and bloody sputum. He denied chest pain, night sweats, weight loss, fever, or chills. Computerized tomography (CT) chest showed a new right lower lobe cavitary nodule measuring 3.4 cm x 2.8 cm and unchanged bilateral apical cavitary lung lesions. Our patient was started on IV piperacillin-tazobactam and vancomycin. He had approximately 150 ml of hemoptysis in 24 hours therefore received inhaled tranexamic acid. Sputum smear was positive for acid fast bacilli. Quantiferon TB and HIV testing were negative. Sputum cultures grew Mycobacterium malmoense. Unfortunately, the patient refused any further treatment. Discussion: Mycobacterium species are seen in patients with underlying lung disease or immunocompromised states. Infection is diagnosed by clinical, radiological, and microbiological workup. Microbiological workup includes two separate sputum samples or via transbronchial biopsy or bronchial wash. The most common radiological finding include thick-walled cavitary lung lesions in the upper lobes and underlying pulmonary fibrosis. This Mycobacterium species has high antimicrobial resistance. As per the current ATS and IDSA guidelines, multidrug treatment with macrolides, ethambutol, and rifamycin for a duration of 12 months is indicated. Conclusion: Non-TB Mycobacterium infrequently causes disease, though in susceptible or immunocompromised individuals, it can cause serious respiratory infections. M. malmoense infection still carries a high mortality risk, so careful and early diagnosis is important to improve outcomes. It is important to recognize patients with non-resolving radiographic imaging as well as atypical and persistent infections that do not improve with standard treatment.

Pulmonary cystic and cavitary lesions caused by diverse etiologies are commonly encountered in chest imaging. The terms "cyst" and "cavity" are used to describe air-filled regions in the center of a nodule or consolidation of the lung. To date, only radiologic aspects of these lesions have been addressed. The morphologies of pulmonary cystic and cavitary lesions exhibit a broad spectrum, ranging from benign to malignant pulmonary diseases of acquired or congenital origin, including variable infectious diseases. In this review, we summarized the differential diagnosis of pathological entities to provide pathologists and radiologists with an overview of the diseases most commonly associated with pulmonary cystic and cavitary lesions in adults and children. The results showed slightly different patterns in the distribution of the diseases in the two groups. The most common causes of cavitary lesions include malignancy and infection in adults, and congenital malformation in children. Therefore, identification of pathologic entities correlating with the radiologic findings, clinical course, and location of the lesion is important in the evaluation of cystic and cavitary lung lesions in order to avoid unnecessary surgical procedures or delayed treatment.

SINGLE CAVITARY LUNG LESION IN A HEALTHY YOUNG MALE

The present study investigates the diagnostic efficiency of apparent diffusion coefficient (ADC) values in differentiating between malignant and benign cavitary lesions on diffusion-weighted magnetic resonance imaging (DWI). This prospective study included 45 consecutive patients identified with a cavitary lung lesion with a wall thickness of ≥5mm on thoracic computed tomography in our clinic between 2020 and 2022, and who underwent thoracic DWI within 1 week of their original computed tomography. ADC measurements were made on DWI by drawing a region of interest manually from the cavity wall, away from the lung parenchyma in the axial section where the lesion was best demonstrated. The patients were then classified into benign and malignant groups based on the pathology or clinico-radiologic follow-up. The sample included 29 (64.4%) male and 16 (35.6%) female patients, with a mean age of 59.06±17.3 years. Included in the study were 1 patient with 3 and 3 patients with 2 cavitary lesions each, with a total for the sample of 50 cavitary lesions. There were 23 (46%) malignant and 27 (54%) benign cavitary lung lesions. The mean ADC value (×10 -3 mm 2 /s) of the malignant and benign cavitary lesions was 0.977±0.522 (0.511 to 2.872) and 1.383±0.370 (0.930 to 2.213), respectively. The findings were statistically significant using an independent samples t test ( P =0.002). The mean wall thickness of the malignant and benign lesions was 12.47±5.51mm (5 to 25mm) and 10.11±4.65mm (5 to 22mm), respectively. Although malignant cavities had a higher mean wall thickness than benign cavities, the difference was statistically insignificant ( P =0.104). A significant difference was identified between the ADC values measured in DWI of the malignant and benign cavitary lung lesions. DWI, a noninvasive and rapid imaging method, can provide useful information for the differential diagnosis of cavitary lesions and can minimize unnecessary biopsies.

Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), is a rare subtype of non-Hodgkin lymphoma that frequently presents with multiorgan involvement. We report a diagnostically challenging case of a female in her late 40s presenting with otomastoiditis, brain abscess and bilateral cavitary lung lesions. A positive serum galactomannan led to empiric antifungal therapy for presumed disseminated aspergillosis. However, tissue biopsies were negative for infection, and histopathology ultimately confirmed PTCL-NOS. This case highlights a rare presentation of PTCL-NOS, involving both the lungs and central nervous system, mimicking invasive fungal disease.

TO CAVITATE OR NOT TO CAVITATE: ATYPICAL PRESENTATION OF A COMMON PATHOGEN

To demonstrate clinical features and outcomes in patients with cavitary lung lesions and COVID-19 associated pneumonia. A retrospective analysis of electronic medical records of 8261 patients with COVID-19 was performed. We selected 40 patients meeting the inclusion criteria. Sex, age, hospital-stay, lung tissue lesion, comorbidities, treatment, methods of respiratory support, complications and outcomes were evaluated. Cavitary lung lesions were more common in men (67.5%). Age of patients ranged from 28 to 88 (mean 64.9±13.7) years. Hospital-stay in patients with cavitary lung lesions was 9-58 (median 27.5) days. There were 18 complications in 14 (35%) patients. Pneumothorax, isolated pneumomediastinum, pleural empyema, hemoptysis and sigmoid colon perforation were considered as complications of cavitary lung lesions. Nine (22.5%) patients died (5 of them with complications). Three patients died after surgical treatment. Long-term results were analyzed in 8 (25.8%) patients. Patients were followed-up for 3 months after discharge. Shrinkage of lesions occurred after 7-60 (mean 23) days, and complete obliteration of cavities came after 32 (range 14-90) days. Cavitary lung lesions are a rare complication of COVID-19 pneumonia. There was no significant correlation of complications with age, sex, therapy, volume of lung lesions and non-invasive ventilation (NIV). Despite more common fatal outcomes in older patients undergoing NIV, the last one was prescribed exclusively due to disease progression and respiratory failure. Further research on this problem is necessary to identify possible risk factors of cavitary lung lesions.

Pulmonary artery sarcoma (PAS) is a rare, poorly differentiated malignancy arising from the intimal layer of the pulmonary artery. Contrast-enhanced chest computed tomography (CT) is a good diagnostic modality that shows a low-attenuation filling defect of the pulmonary artery in PAS patients. An 18-year-old man was referred to our hospital for the evaluation and management of cavitary pulmonary lesions that did not respond to treatment. A contrast-enhanced CT of the chest was performed, which showed a filling defect within the right interlobar pulmonary artery. The patient underwent a curative right pneumonectomy after confirmation of PAS. Although lung parenchymal lesions of PAS are generally nonspecific, it can be presented as cavities indicate pulmonary infarcts. Clinicians must consider the possibility of PAS as well as pulmonary thromboembolism in patients with pulmonary infarcts. So, we report the case with PAS that was diagnosed during the evaluation of cavitary pulmonary lesions and reviewed the literatures.

Cavitary lung lesions pose a formidable diagnostic challenge due to their multifaceted etiologies. While tuberculosis and other prevalent pathogens typically dominate discussions, instances of community-acquired Pseudomonas aeruginosa (P. aeruginosa) pneumonia leading to cavitation in immunocompetent individuals remain exceptionally rare. Herein, we present a compelling case of such pneumonia in a 61-year-old man with a past medical history of hypertension and coronary artery disease who presented with cough, chest pain, and subjective fever. Chest imaging revealed cavitary lung lesions, which is atypical for community-acquired pneumonia (CAP). Initial workup excluded common CAP pathogens, following which bronchoscopy with bronchoalveolar lavage (BAL) definitively diagnosed P. aeruginosa, prompting targeted antibiotic therapy. Treatment led to clinical and radiographic improvement. P. aeruginosa rarely causes CAP, especially in immunocompetent patients, and cavitary lesions further complicate diagnosis. This case highlights the importance of considering P. aeruginosa in CAP with unusual features and emphasizes the utility of bronchoscopy with BAL for diagnosis and guiding management.

Cavitary lung lesion as sequelae of mild COVID-19 in a patient with HIV.

Anaplastic Thyroid Carcinoma (ATC) is a relatively uncommon highly malignant tumour originating from the follicular cells of thyroid gland having poor prognosis. It accounts for 2% to 5% of all thyroid carcinomas and patients typically present with a rapidly growing anterior neck mass with aggressive symptoms. A 53-year-old male presented with diffuse neck swelling measuring 8x6 cm and right cervical lymph node measuring 2x2 cm since one month which was associated with dyspepsia and dyspnoea. Ultrasound and Contrast Enhanced Computed Tomography (CECT) neck revealed enlarged right lobe of thyroid and multiple enlarged cervical lymph nodes with soft tissue density nodules in bilateral lungs. Fine Needle Aspiration (FNA) from the swelling revealed giant cell, spindle cell and squamoid pattern. Focal areas showed follicular epithelial cells arranged in repeated microfollicular pattern suggesting an underlying follicular neoplasm. FNAC smears from the lymph node also revealed similar findings. Based on the cytomorphological and radiological findings, final diagnosis of ATC probably arising from underlying follicular carcinoma with cervical lymph node and lung metastasis was given. FNAC leads to prompt and definitive diagnosis, so that therapy can be initiated as soon as possible for better outcome. Multimodality therapy (surgery, external beam radiation, and chemotherapy) is the mainstay of treatment.

Cavitation and Confusion: A Puzzling Presentation of Granulomatous Disease

AN UNUSUAL PRESENTATION OF MALIGNANCY

Background : In contrast to tuberculous pleurisy, tuberculous empyema is a chronic active infectious disease of the pleural cavity that is frequently accompanied by cavitary or advanced pulmonary lesions. The condition requires long-term anti-tuberculous medication with external drainage. The clinical features and treatment outcome of tuberculous empyema are unclear despite the high prevalence of tuberculosis in Korea. Methods : From January 1991 through April 2004, 17 patients diagnosed with tuberculous empyema in Kyungpook National University Hospital were enrolled in this study. Their medical records and chest radiographs were reviewed. Results : Twelve patients(71%) had a history of tuberculosis and six of the 12 patients were under current anti-tuberculous medication. Productive cough, fever, and dyspnea were the main complaints. There was no predominance between the right and left lungs. Nine patients(53%) had far-advanced pulmonary tuberculosis, two(12%) had a cavitary lesion, and seven(41%) had a pyopneumothorax on the chest radiograph. All eight cases in whom the data of pleural fluid WBC differential count was available showed polymorphonuclear leukocyte predominance. Eight patients(47%) had other bacterial infections as well. The overall rates of a positive sputum AFB smear and culture for M. tuberculosis were 71% and 64%, respectively. The positive AFB smear and culture rates for M. tuberculosis from the pleural fluid were 33% and 36%, respectively. Twelve of the 16 patients(75%) were treated successfully. Three underwent additional surgical intervention. Two patients (12%) died during treatment. Conclusion : Tuberculous empyema is frequently accompanied by advanced pulmonary lesions, and polymorphonuclear leukocytes are predominant in the pleural fluid. Other accompanying bacterial infections in the pleural cavity are also common in tuberculous empyema patients. Therefore, tuberculous empyema should be considered in differential diagnosis of patients with polymorphonuclear leukocyte-predominant pleural effusion. In addition, more active effort will be needed to achieve a bacteriological diagnosis in the pleural fluid.

A 43-year-old female patient is being followed up with a diagnosis of rheumatoid arthritis. She presented with ulcerated lesions on the lower extremity, diffuse subcutaneous nodules, dyspnea, hemoptysis, and fever. Cavitary lesions were detected on the chest X-ray and thoracic computed tomography (Figure 1). The biopsy sample taken from the lesion in the lung was interpreted as “tumor necrosis”. The biopsy sample from subcutaneous nodules was interpreted as ”T-cell/histiocyte-rich large B-cell lymphoma”. There may be some similarities between various lung cavitary lesions, knowledge of the possible causes and a systematic approach will help to narrow down the huge list of differential diagnoses. CAVITY mnemonics can be used for diseases that may cause cavitary lesions in the lung (Table 1) (1). Pulmonary cysts are mimics of emphysema, cystic bronchiectasis, and bullous lung cavitary lesions, and before diagnosing a cavitary lesion, it should be ensured that it is not one of these mimics.