{
  "abstract": "Extraskeletal osteosarcoma arising in the retroperitoneum is exceedingly rare, and its osteoid-producing histology closely mimics dedifferentiated liposarcoma. A 33-year-old woman presented with a 1-month history of progressive abdominal distension. Imaging revealed a 15 cm right retroperitoneal mass with punctate calcifications, no macroscopic fat, and no bone attachment. The mass was resected completely en bloc with negative microscopic margins (R0). Sections showed a high-grade sarcoma weaving through lace-like osteoid. MDM2 immunohistochemistry was negative and fluorescence in situ hybridization (FISH) detected no MDM2 amplification; CDK4 immunostaining and CDK4 FISH were likewise negative. No well-differentiated liposarcoma component was found on gross or microscopic examination, and together these findings ruled out 12q13-15 amplification. The final diagnosis was primary, high-grade extraskeletal osteosarcoma of the retroperitoneum. The patient received adjuvant MAP chemotherapy (methotrexate, doxorubicin, cisplatin) and at 25 months after surgery remains free of recurrence or metastasis; surveillance imaging will continue for at least 10 years. Any osteoid-producing retroperitoneal sarcoma without a well-differentiated liposarcoma component should undergo MDM2 amplification testing, and ideally CDK4 testing, because the two diagnoses are managed differently.",
  "abstract_shown": true,
  "affiliations": [
    "Department of General Surgery, Affiliated Hospital of Hebei University, Baoding, China.",
    "Basic Research Key Laboratory of General Surgery for Digital Medicine, Affiliated Hospital of Hebei University, Baoding, China.",
    "Department of Dermatology, Affiliated Hospital of Hebei University, Baoding, China."
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Xiangxiang Ren"
    },
    {
      "affs": [
        0
      ],
      "name": "Tianhao Xie"
    },
    {
      "affs": [
        1
      ],
      "name": "Linqian Li"
    },
    {
      "affs": [
        0
      ],
      "name": "Xiaoshi Jin"
    },
    {
      "affs": [
        2
      ],
      "name": "Meng Zhang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/c1hx21fbc7bcs.bib",
  "cited_by": 0,
  "doi": "10.3389/fmed.2026.1921181",
  "fulltext_url": "https://europepmc.org/articles/PMC13687667",
  "id": "c1hx21fbc7bcs",
  "issns": [
    "2296-858X"
  ],
  "landing_url": "https://europepmc.org/article/MED/42923544",
  "language": "eng",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2740|Sarcoma Diagnosis and Treatment"
    ]
  ],
  "openalex": "W7221006324",
  "pdf_url": "https://europepmc.org/articles/PMC13687667?pdf=render",
  "pmcid": "PMC13687667",
  "pmid": "42923544",
  "published": "2026-10-08",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/c1hx21fbc7bcs.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:20:33Z",
      "native_id": "MED:42923544",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42923544"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2740|Sarcoma Diagnosis and Treatment",
      "subfield": "general"
    }
  ],
  "title": "Primary extraskeletal osteosarcoma of the retroperitoneum: a case report.",
  "title_text": "Primary extraskeletal osteosarcoma of the retroperitoneum: a case report.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:20:33Z",
  "url": "https://research.draconitic.com/paper/c1hx21fbc7bcs",
  "venue": "Frontiers in medicine",
  "versions": []
}