Lipoblastoma-like tumor of the vulva: A rare benign mesenchymal neoplasm mimicking myxoid liposarcoma

Abstract

Abstract Introduction/Objective Lipoblastoma-like tumor of the vulva (LLTV) is a rare, benign mesenchymal neoplasm of adipocytic differentiation that typically presents as a vulvar mass in young women, clinically mimicking a Bartholin gland abnormality. The tumor is well-circumscribed and multilobulated, composed of mature adipocytes, uniloculated lipoblasts and bland spindle cells. Morphologic features often overlap with lipoblastoma, myxoid liposarcoma, and spindle cell lipoma; however, absent alterations of PLAG1 and HMGA2 distinguish it from lipoblastoma, and lack of DDIT3 gene rearrangement distinguishes it from myxoid liposarcoma. While Rb1 usually demonstrates a “mosaic” pattern of expression, no definitive evidence of a structural abnormality in 13q has been identified. Methods/Case Report A 24-year-old female presented with mild discomfort and persistent swelling of the right vulva for one year, which was initially thought to be a Bartholin gland cyst. Physical examination revealed marked asymmetry between the right and left vulva, and ultrasound examination revealed an ovoid, hypoechoic, and solid- appearing vulvar mass (4.7 x 2.5 x 1.1 cm). She subsequently underwent excision of the vulvar mass for diagnosis and treatment. Results (if a Case Study enter NA) The excision specimen showed a relatively well-circumscribed and multi-lobulated subcutaneous mass with myxoid stroma and thin fibrous septa. The tumor was composed of a mixture of bland spindle cells, uniloculated lipoblasts and mature adipocytes. No significant nuclear atypia, necrosis or mitotic activity was identified. Immunohistochemical stains showed that the tumor cells were negative for keratin cocktail, S100 protein, SMA, and Desmin. CD34 highlighted vessels within the lesion, and Rb1 showed a "mosaic" pattern of weak and negative expression. Conclusion Lipoblastoma-like tumor of the vulva (LLTV) is a rare, benign tumor that tends to occur in young women, often clinically mimicking a Bartholin gland cyst. Recognition of this rare entity with distinction from mimics including myxoid liposarcoma is essential to avoid overly aggressive treatment. Complete conservative excision is recommended.