Vascular tumors of the mediastinum

Abstract

Vascular tumors represent only a sliver of all tumors affecting the mediastinum, but they pose diagnostic challenges due to significant overlap among entities, ever-evolving classification schemes, and the exquisite rarity of some of the entities not only in the mediastinum but in pathology practice as a whole. Most of the vascular tumors are better known to the practice of soft tissue pathology, from which some of the knowledge of clinical behavior can be extrapolated. For example, the stratification of epithelioid hemangioendothelioma (EHE) into two biologically separate categories has effectively translated from the somatic soft tissues to the thorax. For other entities, the effective validation of soft tissue parameters is hindered by the small numbers of reported mediastinal cases. Many of the treatment modalities have also transferred over, with the key differences resting on the difficulty in achieving complete surgical resection for mediastinal tumors as opposed to those in the somatic soft tissues. Accordingly, systemic drug therapies have emerged as attractive options for some of the mediastinal vascular tumors, such as kaposiform hemangioendothelioma (KHE) and Kaposi sarcoma (KS). The categories presented herein mirror the classification scheme set forth by the 5th Edition WHO Classification of Soft Tissue and Bone Tumors. This review focuses on the biologically aggressive vascular neoplasms while limiting discussion of the benign entities to relevant comparisons in the differential diagnoses. While distinguishing among the benign entities has academic importance, in practice, the stakes are far higher for diagnosing the biologically aggressive tumors given their marked heterogeneity in clinical outcomes. Practical advice for problem areas in pathology will be reviewed alongside tumor pathobiology, including the latest in molecular diagnostics.

The surgical treatment of locally advanced angiosarcoma of the anterior mediastinum. A clinical case

“…Все ангиосаркомы возникают из эндотелиальных клеток [2,4]. Опухоль характеризуется агрессивным течением, частым рецидивированием, гематогенным метастазированием (чаще всего в легкие или печень), плохой чувствительностью к химио-и лучевой терапии и неблагоприятным прогнозом [5,6]. Ангиосаркомы подразделяются на 2 группы: веретеноклеточная гемангиоэндотелиома и эпителиоидная гемангиоэндотелиома [2].…”

“…Пятилетняя выживаемость составляет 24% [2,5]. Более 1/2 пациентов умирают в течение 1 года после постановки диагноза [3,6]. Для некоторых нерезектабельных случаев медиана выживаемости составляет всего 7,3 мес [5,4].…”

Benign lesions of the mediastinum

“…It is important to note that especially anastomosing hemangiomas can sometimes resemble well‐differentiated angiosarcomas. However, anastomosing hemangiomas often exhibit distinctive features such as intralesional mature adipose tissue, small thrombi, extramedullary haematopoiesis, and the presence of GNAQ mutations 41 …”

“…However, anastomosing hemangiomas often exhibit distinctive features such as intralesional mature adipose tissue, small thrombi, extramedullary haematopoiesis, and the presence of GNAQ mutations. 41…”

Neurogenic tumours of the posterior mediastinum and differential diagnosis considerations

“…A detailed inventory of soft‐tissue tumours that may be encountered in the mediastinum based on the WHO 2013 classification was published in 2015 1,2,3 . In addition, several comprehensive reviews on mediastinal soft‐tissue pathology are available, including reviews focusing specifically on a single tumour type 4,5,6,7,8 . The spectrum of STTs in the posterior mediastinum is skewed towards those with neurogenic/ganglionic differentiation, given the topological location of elements of the autonomic nervous system and spinal nerve structures in the posterior aspect of the mediastinum.…”