Department of Pathology, Nippon Life Hospital, 2-1-54 Enokojima, Nishi-ku, 550-0006, Osaka, Japan.
Department of Thoracic Surgery, Nippon Life Hospital, Osaka, Japan.
Diagn Pathol. 2022 Oct 12;17(1):77. doi: 10.1186/s13000-022-01260-1.
Thymofibrolipoma has been described as a variant of thymolipoma. To date, 3 cases have been reported, and the lesion have been described to consist of extensive areas of collagenous tissue interspersed with islands of mature adipose tissue and strands of thymic tissue.
A 43-year-old woman had an anterior mediastinal tumor. Macroscopically, the cut surface of the tumor was composed of a yellowish lipomatous component and a uniform whitish fibrous component with elastic stiffness. Microscopically, the tumor was composed of collagenous fibrous tissue with sparse spindle cells, mature adipocytes and strands or islands of thymic tissue. The spindle cells in the fibrous tissue had monoallelic deletion of the 13q14 region and corresponding loss of RB1 and FOXO1A protein expression.
This case report may strengthen the hypothesis that thymofibrolipoma is a neoplastic lesion and a variant of thymolipoma and that thymofibrolipoma and lipofibroadenoma are different names for the same lesion. The name "lipofibroadenoma" was given to the lesion because of its histological resemblance to fibroadenoma of the mammary gland. However, this name does not reflect the pathogenesis of this lesion, and the name "thymofibrolipoma" would be preferable. It will be necessary to discuss whether lipofibroadenoma should be listed as an independent entity in the WHO classification.
胸纤维脂肪瘤被描述为胸腺脂肪瘤的一种变体。迄今为止，已有 3 例报道，病变表现为广泛的胶原组织区域，散布有成熟脂肪组织岛和胸腺组织条索。
一名 43 岁女性有前纵隔肿瘤。大体上，肿瘤的切面由黄色脂肪瘤成分和均匀的白色纤维性成分组成，具有弹性硬度。显微镜下，肿瘤由胶原纤维组织组成，稀疏的梭形细胞、成熟脂肪细胞和胸腺组织条索或岛状结构。纤维组织中的梭形细胞存在 13q14 区域的单等位基因缺失，以及相应的 RB1 和 FOXO1A 蛋白表达缺失。
本病例报告可能支持这样一种假说，即胸纤维脂肪瘤是一种肿瘤性病变，是胸腺脂肪瘤的一种变体，胸纤维脂肪瘤和脂肪纤维腺瘤是同一病变的不同名称。之所以给该病变起名为“脂肪纤维腺瘤”，是因为其组织学上类似于乳腺纤维腺瘤。然而，这个名称并不能反映该病变的发病机制，“胸纤维脂肪瘤”这个名称更为合适。有必要讨论脂肪纤维腺瘤是否应在 WHO 分类中作为一个独立实体列出。
