Case report: Atypical lipomatous tumor of the thigh in a four-year-old girl

• Published in: Frontiers in oncology Vol. 14; p. 1401861
• Main Authors: Ogawa, Itaru, Hakozaki, Michiyuki, Kaneuchi, Yoichi, Suzuki, Takeo, Nikaido, Takuya, Yamada, Shoki, Utsumi, Akihito, Hasegawa, Osamu, Sano, Hideki, Matsumoto, Yoshihiro
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 23-07-2024
• Subjects: adipocytic tumor; atypical lipomatous tumor; child; lipoblastoma; MDM2; murine double minute 2; Oncology; CDK4; lipoblastoma; murine double minute 2; MDM2; cyclin-dependent kinase 4; adipocytic tumor; atypical lipomatous tumor; child
• ISSN: 2234-943X; 2234-943X
• DOI: 10.3389/fonc.2024.1401861

Atypical lipomatous tumors (ALTs) are locally aggressive adipocytic malignancies that frequently occur in middle-aged adults. We report the rare case of an ALT of the thigh that occurred in a 4-year-old girl. Since the tumor was initially diagnosed as a lipoblastoma by incisional biopsy, marginal resection was performed. Histopathological findings of the surgical specimen revealed the proliferation of mature and variously sized adipocytes, as well as ectopic ossification; these features differ from the typical findings of lipoblastoma. Immunohistochemical findings showed nuclear positivity for a murine double minute 2 (MDM2) and cyclin-dependent kinase 4 (CDK4) and negativity for pleomorphic adenoma gene 1 (PLAG1). Fluorescence
hybridization showed abnormal amplification of the
gene. The patient was thus finally diagnosed as having an ALT. No signs of local recurrence or metastasis were noted 1 year postoperatively. This case is instructive in the differential diagnosis of primary adipocytic tumors. Lipoblastomas are the most common adipocytic tumors in children, but if a tumor is located in the deep tissue or imaging findings are not typical, the possibility of ALT should be considered and immunohistochemistry for MDM2 and CDK4 should be added.