{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T18:01:43Z","timestamp":1772820103865,"version":"3.50.1"},"reference-count":10,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T00:00:00Z","timestamp":1772755200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Reports"],"abstract":"<jats:p>Background and Clinical Significance: Myolipoma is a rare benign tumor, typically found in the retroperitoneum and characterized by a combination of mature adipocytes and well-differentiated smooth muscle cells. Myoplipomas usually present a delay in diagnosis due to the painless and slow-growing clinical behavior; therefore, the lesion can reach a large dimension with challenging treatment. Case Presentation: We present the case of a retroperitoneal myolipoma infiltrating the left hip of an 11-year-old male. It was suspected based on magnetic resonance imaging. The patient has been successfully treated with surgical excision without complications. Histological examination revealed mature adipose tissue infiltrating smooth muscle cells. The muscle fibers appeared normal, while the dense connective tissue was infiltrated by clusters of mature lymphocytes. Conclusions: Although myolipoma is extremely rare in male children and has never been reported to infiltrate the hip, it should be considered in the differential diagnosis of fat-containing retroperitoneal masses.<\/jats:p>","DOI":"10.3390\/reports9010077","type":"journal-article","created":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T11:05:44Z","timestamp":1772795144000},"page":"77","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Retroperitoneal Myolipoma with Hip Invasion: A Case Report"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7482-8324","authenticated-orcid":false,"given":"Bassel","family":"El Osta","sequence":"first","affiliation":[{"name":"Faculty of Medecine, Balamand University, Balamand 55251, Lebanon"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2538-2714","authenticated-orcid":false,"given":"Luigi","family":"Di Lorenzo","sequence":"additional","affiliation":[{"name":"Department of Life Sciences, Health, and Health Professions, Link Campus University, 00165 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1677-927X","authenticated-orcid":false,"given":"Andrea","family":"Vescio","sequence":"additional","affiliation":[{"name":"Department of Life Sciences, Health, and Health Professions, Link Campus University, 00165 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4734-6741","authenticated-orcid":false,"given":"Laura","family":"Campanacci","sequence":"additional","affiliation":[{"name":"Third Orthopedic and Traumatologic Clinic Prevalently Oncologic, IRCCS Istituto Ortopedico Rizzoli, 40136 Bologna, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3353-1759","authenticated-orcid":false,"given":"Hassan","family":"Zmerly","sequence":"additional","affiliation":[{"name":"Department of Life Sciences, Health, and Health Professions, Link Campus University, 00165 Rome, Italy"},{"name":"Department of Orthopedics, Villa Erbosa Hospital, Gruppo San Donato, 40129 Bologna, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1051\/sicotj\/2021059","article-title":"An egg in the leg: Case report of an osteochondrolipoma","volume":"7","author":"Debras","year":"2021","journal-title":"SICOT-J"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"641","DOI":"10.3348\/kjr.2011.12.5.641","article-title":"MRI of a subcutaneous myolipoma in the ankle: A case report","volume":"12","author":"Lee","year":"2011","journal-title":"Korean J. Radiol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1186\/1477-7819-3-72","article-title":"Retroperitoneal myolipoma","volume":"3","author":"Behranwala","year":"2005","journal-title":"World J. Surg. Oncol."},{"key":"ref_4","first-page":"737","article-title":"Il lipoleiomioma dell\u2019utero [Lipoleiomyoma of the uterus]","volume":"89","author":"Foglia","year":"1997","journal-title":"Pathologica"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1433","DOI":"10.1148\/rg.245045120","article-title":"From the archives of the AFIP: Benign musculoskeletal lipomatous lesions","volume":"24","author":"Murphey","year":"2004","journal-title":"Radiographics"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"460","DOI":"10.1111\/j.1440-1827.2004.01646.x","article-title":"Myolipoma of the retroperitoneum","volume":"54","author":"Takahashi","year":"2004","journal-title":"Pathol. Int."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1111\/j.1365-2559.1994.tb00603.x","article-title":"Retroperitoneal myolipoma. A tumour mimicking retroperitoneal angiomyolipoma and liposarcoma with myosarcomatous differentiation","volume":"25","author":"Michal","year":"1994","journal-title":"Histopathology"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1007\/s13691-024-00655-9","article-title":"Giant retroperitoneal myolipoma mimicking liposarcoma: Report of a resected case and review of the literature","volume":"13","author":"Mori","year":"2024","journal-title":"Int. Cancer Conf. J."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1097\/PAS.0000000000000737","article-title":"Myolipoma of Soft Tissue: Clinicopathologic Analysis of 34 Cases","volume":"41","author":"Fukushima","year":"2017","journal-title":"Am. J. Surg. Pathol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"250","DOI":"10.3346\/jkms.2001.16.2.250","article-title":"A case of retroperitoneal lipoleiomyoma","volume":"16","author":"Oh","year":"2001","journal-title":"J. Korean Med. 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