CT-guided biopsy of the mediastinal masses. Can anatomical relationships predict complications?

Image-Guided Biopsies and Interventions of Mediastinal Lesions

Optimal assessment of the mediastinal masses is performed by a combination of clinical, radiological and often histological assessments. Image-guided transthoracic biopsy of mediastinal lesions is a minimally invasive and reliable procedure to obtain tissue samples, establish a diagnosis and provide a treatment plan. Biopsy can be performed under Computed Tomography, MRI, or ultrasound guidance, using a fine needle aspiration or a core-needle. In this paper, we review the image-guided strategies and techniques for histologic sampling of mediastinal lesions, along with the related clinical scenarios and possible procedural complications. In addition, image-guided mediastinal drainage and mediastinal ablations will be briefly discussed.

[General Overview of Mediastinal Tumours: Classification, Approaches, Biopsy]

Mediastinal tumours can be a real challenge in terms of diagnostic testing and therapy. One reason for this is that there is a wide range of different tumour types. Even when the tumour is large, many of the affected patients are completely asymptomatic at the time of diagnosis. As a rule, specific types of tumours can be assessed with regard to spatial allocation to a mediastinal compartment. However, if possible, diagnosis should be confirmed via puncture or a biopsy. Various methods are available. Choosing the optimal access route for surgical removal of a mediastinal tumour is an important issue. It must be planned on the basis of the tumour's spatial location, size and extent in imaging. This is the best possible option for low-risk and complete removal of any mediastinal tumour.

[Imaging of Mediastinal Tumors]

In computed tomography, the mediastinum is split into ventral prevascular, middle visceral and dorsal paravertebral compartments. Each compartment contains specific tumours which will be presented and discussed briefly. The focus is on image-based analysis of morphological signs to differentiate between entities using X-rays, ultrasound, CT and MRI. It is however difficult to differentiate between various types of lesions based on morphology and to estimate the grade of malignancy. For this reason, functional imaging techniques like PET and MRI are essential tools for detailed and non-invasive work-up. If a histological tissue examination is required, these tissue samples can be acquired using CT guided biopsies with high diagnostic yield and low complication rates.

Mediastinal sarcomas: experience using fine needle aspiration cytopathology

Fine needle aspiration (FNA) cytology is a sparsely used diagnostic method in the evaluation of mediastinal sarcomas in most medical centers worldwide with most literature citations regarding this category of malignancies consisting of small series and individual case reports. Most of these published studies highlight vascular sarcomas such as epithelioid hemangioendothelioma, and angiosarcoma, various subtypes of liposarcoma including well-differentiated liposarcoma, myxoid liposarcoma, and pleomorphic liposarcoma, malignant peripheral nerve sheath tumor, and sarcomas of uncertain differentiation, primary synovial sarcoma and the Ewing sarcoma family of tumors. This paucity of cytopathology reports regarding mediastinal sarcomas is in marked contrast to the almost daily application of endobronchial ultrasound (EBUS)-guided FNA biopsy for sampling mediastinal lymph nodes and mediastinal masses for primary and metastatic carcinomas which, of course, are considerably more common that any type of sarcoma in this location. EBUS, endoscopic ultrasound-guided (EUS) needle biopsy, and percutaneous image-guided biopsy using either core needle, fine-needle, or both can serve a potentially useful role for diagnostic sampling of mediastinal sarcomas, be they primary or metastatic. This review catalogues much of the published data regarding FNA cytopathology and its application to mediastinal sarcomas. An attempt is made to primarily highlight case series rather than individual case reports; however, due to the paucity of these, case reports are cited and discussed where appropriate.