The pathology of mesenchymal tumors of the mediastinum

Soft tissue tumors of the mediastinum (MST) are rare, but can pose considerable diagnostic and differential diagnostic problems due to morphological overlap with non-mesenchymal tumors. Many MST occur in quite typical mediastinal compartments, in typical age groups or with a specific gender predilection, or show important clinical clues. Consideration of clinical, epidemiological and anatomic background information is therefore essential to reach a correct diagnosis. With very few exceptions, the morphology and molecular features of MST are identical to their respective counterparts elsewhere in the body, although their prognosis may be different due to, e.g., late diagnosis, anatomic restrictions and the possible extent of surgical interventions. In the era of personalized medicine, many MST require both an extended panel of immunohistochemical antibodies and molecular tests for their diagnosis. In this brief review, we will outline a practical pathohistological approach to MST that tries to incorporate morphological and clinical features that aid in the diagnosis.