Surgical resection is sufficient for incidentally discovered solitary pulmonary nodule caused by nontuberculous mycobacteria in asymptomatic patients

Beyond Symptoms: Radiologic identification of asymptomatic Mycobacterium avium complex pulmonary infections

BACKGROUND

Although international nontuberculous mycobacterial pulmonary disease (NTM-PD) guidelines highlight symptom presence at diagnosis, the clinical characteristics of asymptomatic Mycobacterium avium complex pulmonary infection (MAC-PI) patients remain understudied. We clarified the clinical characteristics and course of asymptomatic MAC-PI patients.

METHODS

We retrospectively analyzed 200 consecutive patients with MAC-PIs and adequate available data who newly met the microbiological and radiological criteria for NTM-PD at Fukujuji Hospital from January 2018 to June 2020. We compared the clinical characteristics and course of asymptomatic patients with symptomatic patients and evaluated factors influencing treatment initiation through multivariate analysis.

RESULTS

111 patients were symptomatic and 89 were asymptomatic at diagnosis. While the proportion was significantly lower than that in the symptomatic group (28.8 %), 15.7 % of asymptomatic group patients had cavitary lesions (P = 0.042). In the asymptomatic group, treatments were initiated in 38 (42.7 %) patients, and cavitary lesions, a positive acid-fast bacilli smear, and younger age were independent risk factors for treatment initiation. Among 22 (57.9 %) patients who experienced disease progression necessitating treatment during follow-up, 13 (34.2 %) displayed radiological progression without any worsening of symptoms. Agents used for treatment were consistent across the groups, with no significant differences in culture conversion, microbiological recurrence rates, or spontaneous culture conversion rates.

CONCLUSION

Routine health checkups and radiological examinations can detect clinically important MAC-PIs even in the absence of symptoms. Considering that the clinical course of asymptomatic MAC-PI patients is largely similar to that of symptomatic patients, timely and appropriate management and intervention are essential for all MAC-PI patients.

Lobectomy for Suspected Lung Cancer Without Prior Diagnosis

BACKGROUND

We describe use, patients, and outcome of diagnostic lobectomy for suspected lung cancer without pathologic confirmation.

METHODS

A retrospective review of consecutive lobectomy or bilobectomy for suspected or confirmed primary pulmonary malignancy was conducted using our participant's sample of The Society of Thoracic Surgeons database. Surgeons performed lobectomy based on clinical diagnosis or confirmation on a biopsy specimen. Lung cancer confirmed by biopsy specimen was compared with cases clinically suspected. Univariate and multivariate analyses identified variables associated with lobectomy without biopsy specimen confirmation.

RESULTS

Among 2651 lobectomies performed between 2006 and 2019 in 2617 patients, lung cancer was confirmed by preoperative biopsy specimen in 51.6% (1368 of 2651) or was clinically suspected before the operation in 48.4% (1283 of 2651). The intraoperative biopsy specimen in 585 of 1283 cases (45.6%) proved lung cancer before lobectomy, whereas lobectomy proceeded in 698 cases (54.4%) without a diagnosis. Final pathology proved lung cancer in 90% (628 of 698) without a diagnosis before lobectomy and nonmalignant disease in 10% (70 of 698). Nonneoplastic pathology included granulomas (30 of 70 [43%]), pneumonia (12 of 70 [17%]), bronchiectasis (7 of 70 [10%]), and other lesions (21 of 70 [30%]). Operative mortality was 0.94% (25 of 2651) for the cohort and 1.0% (7 of 698) for diagnostic lobectomy only. Multivariate analysis identified patient age, type of lobectomy (right middle lobe), and the intermediate study tercile as associated with diagnostic lobectomy.

CONCLUSIONS

Lobectomy for suspected lung cancer without diagnosis is common, represents practice variation, and infrequently (10% diagnostic, 2.6% all lobectomies) removes nonmalignant disease. Tissue confirmation before lobectomy is preferred, particularly when operative risk is increased. Diagnostic lobectomy is acceptable in carefully selected patients and lesions.

Undiagnosed solitary caseating granulomas: Is lung resection surgery a feasible method for diagnosis and treatment?

BACKGROUND

In many patients, low-dose computed tomography (CT) screening for lung cancer reveals asymptomatic pulmonary nodules. Lung resection surgery may be indicated in these patients; however, distinguishing malignancies from benign lesions preoperatively can be challenging.

METHODS

From 2013 to 2018, 4181 patients undergoing surgery for pulmonary nodules were reviewed at National Taiwan University Hospital, and 837 were diagnosed with benign pathologies. Only patients with pathological diagnosis as caseating granulomatous inflammation were included, sixty-nine patients were then analyzed for preoperative clinical and imaging characteristics, surgical methods and complications, pathogens, medical treatment and outcomes. Mycobacterial evidence was obtained from the culture of respiratory or surgical specimen.

RESULTS

Overall, 68% of the patients were asymptomatic before surgery. More than half of the nodules were in the upper lobes, and all patients underwent video-assisted thoracoscopic surgery (VATS). Some patients (14.5%) developed grade I complications, and the mean postoperative hospital stay was 4 days. The final pathology reports of 20% benign entities postoperatively, and caseating granulomatous inflammation accounted for a significant part. MTB and NTM were cultured from one-fourth of the patients respectively. All patients with confirmed MTB infection received antimycobacterial treatment, while the medical treatment in NTM-infected patients was decided by the infectious disease specialists. The mean follow-up period was 736 days, and no recurrence was found.

CONCLUSION

Lung resection surgery is an aggressive but safe and feasible method for diagnosing MTB- or NTM-associated pulmonary nodules, and, potentially, an effective therapeutic tool for patients with undiagnosed MTB- or NTM-associated pulmonary nodules.

Analysis of pulmonary nodules caused by nontuberculous mycobacteriosis in 101 resected cases: multi-center retrospective study

Background

Solitary pulmonary nodules caused by nontuberculous mycobacteriosis are included as a category of pulmonary nontuberculous mycobacterium disease. Clinical characteristics, treatments and prognosis are not fully known because there are a few related reports.

Methods

This was a multi-center retrospective study of 101 cases diagnosed as solitary nodular type of nontuberculous mycobacteriosis from January 2000 to March 2017 that underwent resection at 9 related facilities belonging to the Thoracic Surgery Study Group of Osaka.

Results

The most common pathogen was Mycobacterium avium complex (n=77, 87.5%), followed by Mycobacterium kansasii (n=8, 9.1%). Chest computed tomography results showed subpleural locations that were difficult to distinguish from lung cancer. Fluorodeoxyglucose positron emission tomography/computed tomography was performed in 58 cases and positive results were obtained in 35 (60.3%), with an average maximum standardized uptake value of 3.87. The purpose of resection in most cases was for diagnosis. The surgical procedure was wedge resection in 87, segmentectomy in 3, and lobectomy in 11, while 77 underwent thoracoscopic surgery. Postoperative complications occurred in 7 cases, though no infections caused by nontuberculous mycobacteriosis were noted. The median observation period was 27 months. A worsened condition occurred in 10 (9.9%) with Mycobacterium avium complex, though none had local recurrence.

Conclusions

Solitary pulmonary nodules due to nontuberculous mycobacteriosis is difficult to diagnose based on preoperative examination results or distinguish from lung cancer. Among the present cases, none had local complications or recurrence, even in those that underwent a wedge resection, thus postoperative chemotherapy was not considered necessary if a complete resection was performed. On the other hand, some cases showed reinfection after a long period following resection, thus patients should be informed of that future possibility.