Gonçalves Francisco, Silva Veiga Ricardo L, Ventura Hugo
Internal Medicine, Centro Hospitalar Tondela Viseu, Viseu, PRT.
Internal Medicine, Hospital de São Teotónio, Viseu, PRT.
Cureus. 2024 Nov 15;16(11):e73718. doi: 10.7759/cureus.73718. eCollection 2024 Nov.
Mesenchymal chondrosarcoma (MCS) is a rare, aggressive subtype of chondrosarcoma characterized by biphasic histology, often misdiagnosed due to its rarity and histological resemblance to other small round cell tumors. It predominantly affects adolescents and young adults. We report a 27-year-old male presenting with a progressively enlarging, painless mass in the right inframammary region, initially attributed to muscular strain. Over one month, the mass rapidly increased in size, accompanied by mild pain exacerbated by movement. Physical examination revealed a firm, non-tender mass approximately 10 x 5 cm in diameter between the sixth and seventh ribs. Contrast-enhanced CT revealed a large expansile lytic lesion of the right sixth rib (10 × 5.5 cm) with cortical destruction, pathological fracture and soft tissue invasion into surrounding musculature. Core needle biopsy revealed a biphasic tumor comprising undifferentiated mesenchymal cells and islands of well-differentiated hyaline cartilage. Immunohistochemical staining showed positivity for vimentin, CD99 and S100 protein with a high Ki-67 proliferation index (30-40%). These findings were consistent with MSC. 18-Fluorodeoxyglucose-positron emission tomography (FDG-PET) scan detected widespread skeletal metastases involving the spine, humerus, scapula, ribs, pelvis and femur. A multidisciplinary team initiated neoadjuvant anthracycline-based chemotherapy to reduce tumor burden and manage systemic disease, with plans for potential surgical intervention upon reassessment. Given the typically poor prognosis associated with MCS, it should be considered in the differential diagnosis of bone tumors in young adults presenting with atypical musculoskeletal masses. Prompt diagnostic workup, including advanced imaging and comprehensive histopathological and immunohistochemical analysis, is essential for accurate diagnosis. A multidisciplinary approach to management is imperative to address the aggressive nature of MCS. Early detection and intervention remain key factors in enhancing survival rates and quality of life for patients afflicted with this formidable malignancy.
间叶性软骨肉瘤（MCS）是一种罕见的、侵袭性软骨肉瘤亚型，具有双相组织学特征，常因其罕见性以及在组织学上与其他小圆细胞肿瘤相似而被误诊。它主要影响青少年和年轻成年人。我们报告一例27岁男性，其右乳房下区域出现一个逐渐增大的无痛性肿块，最初被认为是肌肉拉伤。在一个多月的时间里，肿块迅速增大，并伴有轻度疼痛，活动时加重。体格检查发现第六和第七肋骨之间有一个直径约10×5 cm的质地坚硬、无压痛的肿块。增强CT显示右第六肋骨有一个大的膨胀性溶骨性病变（10×5.5 cm），伴有皮质破坏、病理性骨折以及软组织侵犯周围肌肉组织。粗针活检显示为双相肿瘤，由未分化间叶细胞和分化良好的透明软骨岛组成。免疫组化染色显示波形蛋白、CD99和S100蛋白呈阳性，Ki-67增殖指数较高（30 - 40%）。这些发现与间叶性软骨肉瘤相符。18-氟脱氧葡萄糖正电子发射断层扫描（FDG-PET）检测到广泛的骨骼转移，累及脊柱、肱骨、肩胛骨、肋骨、骨盆和股骨。一个多学科团队启动了以蒽环类药物为基础的新辅助化疗，以减轻肿瘤负荷并控制全身疾病，并计划在重新评估后进行潜在的手术干预。鉴于间叶性软骨肉瘤通常预后较差，对于出现非典型肌肉骨骼肿块的年轻成年人骨肿瘤的鉴别诊断中应考虑到该病。及时进行诊断性检查，包括先进的影像学检查以及全面的组织病理学和免疫组化分析，对于准确诊断至关重要。采用多学科方法进行管理对于应对间叶性软骨肉瘤的侵袭性至关重要。早期发现和干预仍然是提高患有这种可怕恶性肿瘤患者生存率和生活质量的关键因素。
