Spindle Cell Lipoma (SCL) is a benign neoplasm composed of adipocytes and spindle cells within a fibromyxoid stroma containing rope-like collagen fibers and mast cells, being rare in the oral cavity. A 47-year-old male presented with a solitary, well-circumscribed nodule of 4 cm in the right buccal mucosa, similar to the surrounding tissue, where a peduncle attached it. The lesion was so large that the patient developed a parafunctional habit of chronic cheek biting on the lesion’s side. Microscopically, it comprised variable quantities of adipocytes, myxoid matrix, bland spindle cells characterized by elongated, oval-shaped nuclei positive for CD34 in immunohistochemical stain, and dense rope-like collagen fibers. Mast cells were present, positive to toluidine blue, findings compatible with a SCL. The median size of SCL ranges from 1 to 5 cm, being more common in females. Classical findings compromise mature lipomatous tumors with bland spindle cells in a myxoid ground stroma. Its differential diagnosis encompasses lipoma, well-differentiated liposarcoma, myxoid liposarcoma, and non-lipomatous tumors rich in spindle cell components. It is important to not mislead atrophic changes with true lipoblasts and to remember that these cells are uncommon in well-differentiated liposarcoma. The CD34 positivity in these tumors supported the SCL diagnosis. Oral SCL is a rare lipoma variant requiring careful morphological and immunohistochemical evaluation to avoid confusion with liposarcomas and other spindle cell neoplasms. Conservative excision is curative, and recurrence is uncommon. The patient remains recurrence-free after 2 years and 4 months of follow-up.
Silva et al. (Sun,) studied this question.
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