Pulmonary nodules and masses in lung transplant recipients: clinical and CT findings

The role of radiology in addressing the challenge of lung cancer after lung transplantation

The importance of lung cancer as a complication of lung transplantation is increasingly recognised. It may become an important survival-limiting factor in lung transplant patients as management of other complications continues to improve and utilisation of extended criteria donors grows. Radiology can play a key role in tackling this issue at multiple stages in the transplantation pathway and follow-up process. Routine chest CT as part of pre-transplant recipient assessment (and donor assessment if available) can identify suspicious lung lesions with high sensitivity and detect chronic structural lung diseases such as pulmonary fibrosis associated with an increased risk of malignancy post-transplant. Pre-transplant CT also provides a comparison for later CT studies in the assessment of nodules or masses. The potential role of regular chest CT for lung cancer screening after transplantation is less certain due to limited available evidence on its efficacy. Radiologists should be cognisant of how the causes of pulmonary nodules in lung transplant patients may differ from the general population, vary with time since transplantation and require specific recommendations for further investigation/follow-up as general guidelines are not applicable. As part of the multidisciplinary team, radiology is involved in an aggressive diagnostic and therapeutic management approach for nodular lung lesions after transplant both through follow-up imaging and image-guided tissue sampling. This review provides a comprehensive overview of available clinical data and evidence on lung cancer in lung transplant recipients, and in particular an assessment of the current and potential roles of pre- and post-transplant imaging. KEY POINTS: • Lung cancer after lung transplantation may become an increasingly important survival-limiting factor as mortality from other complications declines. • There are a number of important roles for radiology in tackling the issue which include pre-transplant CT and supporting an aggressive multidisciplinary management strategy where lung nodules are detected in transplant patients. • The introduction of routine surveillance chest CT after transplant in addition to standard clinical follow-up as a means of lung cancer screening should be considered.

Diagnosis and treatment of cryptococcal osteomyelitis in a pediatric lung transplant patient

BACKGROUND

Asymptomatic pulmonary nodules may appear at any point after lung transplantation. The differential diagnosis is broad and includes serious life-threatening disease entities.

METHODS

A retrospective case report of a single patient who developed a pulmonary nodule after lung transplantation.

RESULTS

At 2 years post-transplant, an 11-year-old with cystic fibrosis was asymptomatic and had normal lung function. A single nodule was noted on surveillance chest CT scan. Initial evaluation was negative, but subsequently, he was diagnosed with cryptococcal osteomyelitis in a thoracic rib. He responded well to an extended course of antifungal therapy without loss of allograft function or infectious complications.

CONCLUSION

Pulmonary nodules after lung transplantation may be a harbinger of serious complications. A systematic approach to evaluation and follow-up is recommended.

The pulmonary nodule following lung transplantation

The clinical scenario of a pulmonary nodule following lung transplantation is one with limited experience and no supporting guidelines for the approach to diagnosis and management. Given the broad differential diagnosis for pulmonary nodules in this setting, most of which are life-threatening without appropriate treatment, aggressive evaluation is required. Here we present a case of a 70-year-old female with the development of a large pulmonary nodule in the native lung four years following a single lung transplant. She underwent bronchoscopy with endobronchial ultrasound to achieve a tissue diagnosis which showed small cell lung carcinoma. The patient was started on chemotherapy and has shown clinical and radiographic improvement at most recent follow up seven months after the initial diagnosis. In this report we discuss the differential diagnosis and corresponding imaging findings for the pulmonary nodule following lung transplantation to aid in guiding clinicians navigate this challenging clinical situation.

New opacities in lung allograft after transbronchial cryobiopsy

BACKGROUND

The occurrence of radiological opacities post-transbronchial cryobiopsy may pose serious difficulties in differential diagnosis and management of lung allografts. This prospective study evaluated the frequency, characteristics, and evolution of new lung opacities after performing transbronchial cryobiopsy.

METHODS

From February 2018 to June 2018, 22 of 51 consecutive patients with an indication for transbronchial cryobiopsy underwent computed tomography (CT) of the thorax before and at 1, 4, and 8 weeks post-cryobiopsy. New CT images, required by the transplant team, were also evaluated during the next 6 months. Histological findings of transbronchial cryobiopsy and microbiological studies on bronchoalveolar lavage were evaluated as risk factors for opacities.

RESULTS

After obtaining 112 cryobiopsy samples, 46 opacities >10 mm, including ground-glass, solid, cavitated, or a combination of these lesions were observed in 20 (91%) patients on post-cryobiopsy CT. All ground-glasses opacities on CT disappeared at 4 weeks. A single cavitated opacity persisted at 6 months. The remaining opacities disappeared or were decreased to <10 mm by 8 weeks. No correlations of the number, type, or evolution of opacities with the number or volume of cryobiopsy samples obtained, or with the histological diagnosis, type of transplant, or microbiologic culture results were observed.

CONCLUSION

New pulmonary opacities >10 mm occur frequently after transbronchial cryobiopsy; a few may persist beyond 6 months. CT studies are recommended before implementing transbronchial cryobiopsy, whenever possible.

Utility of transthoracic needle biopsy after lung transplantation

The purpose of this study was to assess the diagnostic yield and complications of CT-guided transthoracic needle biopsy (TTNB) after lung transplantation. A database search identified all TTNB performed in lung transplant patients over a 14-year period. Forty-two biopsies in transplant patients (transplant group) were identified and matched to the next biopsy performed in native lungs by the same operator (nontransplant group) as a control. Primary outcomes recorded were diagnosis, diagnostic yield, pneumothorax requiring intervention, and symptomatic pulmonary hemorrhage. Biopsy outcomes were classified as diagnostic, not specifically diagnostic, and nondiagnostic. Patients in the transplant group were younger (P < .002). Emphysema along the biopsy trajectory was more commonly seen in the nontransplant group (P < .0006). Needle gauge, size of lesion, pleural punctures, lesion depth, and number of passes were not significantly different. Diagnostic yield was 71% in the transplant group and 91% in the nontransplant group. There were 20 of 42 (48%) malignant nodules in the transplant group compared to 31 of 44 (70%) nodules in the nontransplant group (P = .05). There were no complications in the transplant group. The nontransplant group had two pneumothoraces requiring intervention. TTNB after lung transplant is safe with a moderate diagnostic yield. Nonmalignant lesions are more common after lung transplantation.