Mediastinal tumours and pseudo-tumours: a comprehensive review with emphasis on multidisciplinary approach

Abstract

The diagnosis of a mediastinal mass may be challenging for clinicians, since lesions arising within the mediastinum include a variety of disease entities, frequently requiring a multidisciplinary approach. Age and sex represent important information, which need to be integrated with imaging and laboratory findings. In addition, the location of the mediastinal lesion is fundamental; indeed, we propose to illustrate mediastinal diseases based on the compartment of origin. We consider that this structured approach may serve as hint to the diagnostic modalities and management of mediastinal diseases. In this review, we present primary mediastinal tumours in the evolving context of new diagnostic and therapeutic tools, with recently described entities, based on our own experience with >900 cases encountered in the past 10 years.

FIGURE 1

Radiological and pathological appearance of a SMARCA4-deficient tumour. a) Initial chest radiograph and computed tomographic (CT) scan showing a mediastino-pulmonary tumour (*) with positivity on positron emission tomography; b) histology of the initial biopsy at medium magnification showing an undifferentiated tumour infiltrating fat, with mitoses and necrosis (*; top right); c) post-chemotherapy chest radiograph and CT scan showing tumour regression and macroscopic appearance of the surgical specimen showing a necrotic tumour infiltrating the left pulmonary upper lobe lung and pericardium (*).

FIGURE 2

Radiological and pathological typical features of a multilocular thymic cyst. a) Computed tomographic (CT) scan showing the lesion in the anterior mediastinum; b) positron emission tomography showing a moderate hypermetabolism (standardised uptake value 3.7); c) gross appearance of the multilocular cystic lesion; d) histological appearance at low magnification showing several cavities with thick fibroinflammatory walls.

FIGURE 3

Radiological and histological typical features of Müllerian cysts of the mediastinum. a, b) Magnetic resonance imaging showing a paravertebral cystic lesion; c) histological features at low magnification showing a cystic lesion resembling a fallopian tube; d) histological appearance of the ciliated epithelium of the cyst at high magnification; e) immunohistochemistry showing strong oestrogen receptor nuclear expression.