Overview of Lipoblasts and Mimics

Overview of Lipoblasts and Mimics

David R. Lucas, MD

Lipoblasts come in a variety of sizes and shapes. The cytoplasm is filled with lipid that appears as 1 or multiple clean, punched-out vacuoles that indent and scallop the nucleus.

Malignant lipoblasts are required to diagnose pleomorphic liposarcoma. This lipoblast has a large hyperchromatic nucleus image sharply indented by multiple lipid-filled vacuoles image.



  • Lipoblasts are embryonic mesenchymal cells that develop into fat cells

    • Wide spectrum of cell morphology

      • Primitive spindle cells with small cytoplasmic vacuoles

      • Univacuolated or multivacuolated round cells

      • Signet ring cells

  • Neoplastic lipoblasts morphologically recapitulate developmental stages of lipogenesis

    • Malignant lipoblasts characterized by nuclear hyperchromasia and atypia

      • Peripheral crescentic nuclei

      • Multilobated nuclei

      • Multinucleated giant lipoblasts


  • Lipoblasts are not required for diagnosing all types of liposarcomas

    • Atypical lipomatous tumor/well-differentiated liposarcoma

      • Lipoblast often present but not required for diagnosis

      • Defined by presence of atypical stromal cells

    • Myxoid/round cell liposarcoma

      • Highly variable numbers of lipoblasts present in a given tumor

      • Wide spectrum in appearance of lipoblasts

      • Univacuolated round cells, multivacuolated cells, signet ring cells

    • Pleomorphic liposarcoma

      • Identification of lipoblasts is required for diagnosis

      • Often contain very large pleomorphic and multinucleated lipoblasts

      • Lipoblasts sometimes sparse

  • Lipoblasts are not pathognomonic of liposarcoma

    • Lipoblasts can be found in benign tumors

      • e.g., lipoblastoma

      • e.g., lipoblastic nerve sheath tumor

Jul 9, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Overview of Lipoblasts and Mimics
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