Atypical lipomatous tumor, which may also be designated as well-differentiated liposarcoma(WDL), depending on the tumor location, is a low-grade liposarcoma that may arise in the head and neck region. Liposarcomas are classified into 4 histologic types: well differentiated, myxoid, round cell, and pleomorphic. Well-differentiated liposarcomas are further classified into the following 4 subtypes based on microscopic features: adipocytic, sclerosing, inflammatory, and spindle cell.1Use of the terms ALTand WDLis determined primarily by tumor location and resectability. Considerable debate and confusion exist within the pathology and surgical literature as to the exact distinction between these 2 terms. Typically, tumors of the retroperitoneum, mediastinum, cervical muscles, pharynx, or larynx, sites in which it is commonly impossible to achieve clean wide surgical excision margins, are called WDLs, while ALTis used for tumors that arise in oral cavity, salivary glands, and other superficial, surgically accessible areas.2Although there are differences in the naming of these tumors, ALTs are histologically identical to WDLs, but ALTs generally have a better prognosis because they are more amenable to complete surgical resection.
Pathology Quiz Case 2: Diagnosis. Arch Otolaryngol Head Neck Surg. 2008;134(9):1014-1015. doi:10.1001/archotol.134.9.1014-b