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Extraskeletal myxoid chondrosarcoma of gluteal region mimicking intergluteal abscess in a 9-year-old girl
Tunç Tığlı 1, Mithat Haliloğlu 2, Diclehan Orhan 3, Ali Varan 4, Tutku Soyer 1, Özlem Boybeyi 1
1 Hacettepe University Faculty of Medicine Department of Pediatric Surgery
2 Hacettepe University, Faculty of Medicine, Department of Radiology, Division of Pediatric Radiology
3 Hacettepe University, Faculty of Medicine, Department of Pathology
4 Hacettepe University, Faculty of Medicine, Department of Pediatric Oncology
Background:
Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue tumor which typically occurs in adults. EMC is rarely seen in children, predominantly arises in the lower extremities, head and neck region. However, gluteal involvement in a pediatric patient has not been previously documented. Herein, a case with ECM arising in the gluteal subcutaneous tissue of a 9-year-old girl, initially thought to be a intergluteal abscess was reported.
Case report:
The patient admitted with a painless subcutaneous mass in the gluteal region. There were no associated systemic complaints. A well-defined, mobile, and elastic subcutaneous mass measuring 4×5 cm was palpated having an intact overlying skin. MRI revealed a well-circumscribed, lobulated mass located in the midline subcutaneous adipose tissue of the gluteal region with a diameter of 45×35×32 mm. The lesion appeared hyperintense on T2-weighted sequences and exhibited heterogeneous enhancement following contrast administration without any infiltration of adjacent musculature or pelvic structures. Surgical exploration revealed an encapsulated mass easily separable from surrounding tissues. The mass was completely excised. Histopathologic examination revealed uniform spindle to oval cells arranged in cords and strands within abundant myxoid stroma. Immunohistochemistry showed diffuse positivity for vimentin and S100, while epithelial and myogenic markers were negative. FISH analysis for NR4A3 rearrangement yielded a negative result. The findings were consistent with diagnosis of EMC. The post-operative PET-CT revealed absence of any detectable metastasis, so adjuvant treatment was not administered. The patient is still under follow-up uneventfully.
Conclusion:
Gluteal localization of EMC has not been previously described in the pediatric population. This case highlights the importance of considering malignant soft tissue tumors in the differential diagnosis of atypical subcutaneous lesions in children. Complete surgical excision remains the cornerstone of treatment.