Fig. 2

Histologic images of lipomatous tumors. A The image shows the characteristic histology of lipoma: a homogeneous proliferation of mature adipocytes without cellular atypia. B The adipocytic (lipoma-like) type of atypical lipomatous tumor (ALT) consists of adipocytes with variation in size and shape and a typical component of stromal spindle cells with hyperchromatic atypical nuclei. C Liposarcomas with low-grade dedifferentiation are rare but recognized increasingly. The tumor frequently shows dense proliferation of uniform spindle cells with mild nuclear atypia arranged in a fascicular pattern. D The dedifferentiated areas of high-grade dedifferentiated liposarcoma usually resemble undifferentiated pleomorphic sarcoma or myxofibrosarcoma. However, any type of high-grade sarcoma can be present. The actual image shows high-grade spindle cell sarcoma with features of fibrosarcoma. All images are in hematoxylin and eosin stain. The black bar indicates 100 μm