(BQ) Part 2 book "Practical soft tissue pathology - A diagnostic approach" presentation of content: Biphasic tumors and tumors with mixed patterns, adipocytic tumors, vascular tumors, cartilaginous and osseous soft tissue tumors, cutaneous mesenchymal tumors, mesenchymal tumors of the gastrointestinal tract, lower genital soft tissue tumors, applications of molecular testing to differential diagnosis,. | 9 Biphasic Tumors and Tumors with Mixed Patterns Alessandra F. Nascimento, MD, and Jason L. Hornick, MD, PhD Biphasic Synovial Sarcoma 235 Mixed Tumor/Myoepithelioma/Myoepithelial Carcinoma 238 Malignant Peripheral Nerve Sheath Tumor with Divergent (Heterologous) Differentiation (Including Glandular Type) 239 Ectopic Hamartomatous Thymoma 241 Gastrointestinal Stromal Tumor, Mixed Type 243 Dedifferentiated Liposarcoma 244 Melanotic Neuroectodermal Tumor of Infancy 246 Nonmesenchymal Tumors with Biphasic and Mixed Patterns 248 Soft tissue tumors with biphasic histologic features are uncommon. The “biphasic” designation is often applied to tumors with mixed spindle cell and overtly epithelial (often glandular) components, but can also be applied to tumors with mixed spindle cell and epithelioid morphologic features without epithelial differentiation. The classic example of a soft tissue tumor with such a pattern is biphasic synovial sarcoma, which when arising at typical anatomic sites, is sufficiently histologically distinctive to allow for straightforward recognition in most cases. However, a small group of other soft tissue tumors may include similar combinations of morphologic cell types and may therefore be confused with biphasic synovial sarcoma (Box 9-1). In addition, some soft tissue tumors characteristically show marked intratumoral heterogeneity in terms of both cell types and growth patterns (see Box 9-1). Awareness of the tumors that most often show such mixed patterns can facilitate proper diagnosis. A relatively common example is dedifferentiated liposarcoma, which, in addition to the obvious combination of well-differentiated liposarcoma and a non lipogenic component (see Chapters 7 and 12), often shows striking heterogeneity when sampled thoroughly. Such heterogeneity in a retroperitoneal or intra-abdominal tumor (for example) can be a helpful clue to the diagnosis. Finally, some soft tissue sarcomas typically contain heterologous elements .
