Histology-Driven Therapy: The Importance of Diagnostic Accuracy in Guiding Systemic Therapy of Soft Tissue Tumors.

Soft tissue tumors (STTs) are rare mesenchymal neoplasms accounting for less than 1% of adult cancers. More than 50 different subtypes of STTs have been identified, with this number expected to grow as our understanding of the complex genetic landscape of these diseases improves. As the classification of soft tissue neoplasms continues to diversify, so does the approach to therapy. Accurate histopathologic diagnosis, utilizing the appropriate ancillary immunohistochemical and molecular diagnostic platforms, underpins the oncologic management of soft tissue sarcomas. As increasing numbers of reproducible genetic abnormalities in soft tissue neoplasms are defined, molecular genetic and molecular cytogenetic investigations have become a standard part of the ancillary diagnostic repertoire. However, other soft tissue neoplasms lack reproducible genetic abnormalities, and for these, traditional histology and immunohistochemistry remain the cornerstones for diagnosis. Here, we give an overview of histology-driven therapy in STTs, highlighting the critical role of accurate surgical pathology in guiding the systemic treatment of patients with these neoplasms, and the importance of close collaboration between the surgical pathologist and the oncologist. We also summarize what is considered standard practice in nonhistology- and histology-driven therapy.