Lipoblastoma-Like Tumor: A Case Report From Costa Rica.

Lipoblastoma-like tumors (LLTs) are rare adipocytic neoplasms, most commonly found in the vulvar region. Their histopathological and molecular features often overlap with other adipocytic tumors, making diagnosis challenging. We report the case of a 41-year-old woman who presented with a painless mass in the right labia majora. An initial excisional biopsy confirmed a lipoblastoma-like tumor, characterized by spindle cells in a myxoid stroma, focal positivity for CD34 and S100, and absence of DDIT3 rearrangement. Imaging revealed residual nodular lesions, prompting a wide local excision, which achieved negative margins. No recurrence was observed during a 24-month follow-up. LLTs pose diagnostic challenges due to their morphological similarities with lipoblastoma, myxoid liposarcoma, spindle cell lipoma, and atypical spindle cell/pleomorphic lipomatous tumor (ASCPLT). Immunohistochemical and molecular analyses, especially the absence of DDIT3 and PLAG1 rearrangements, are essential for accurate diagnosis. Surgical excision with clear margins remains the treatment of choice, and long-term monitoring is advised due to the potential, though rare, risk of recurrence or metastasis. LLTs should be considered in the differential diagnosis of vulvar soft tissue masses. Accurate histopathological and molecular evaluation, combined with appropriate surgical management, ensures favorable outcomes and helps avoid unnecessary interventions.