Division of Anatomic Pathology, Mayo Clinic, Rochester, MN.
Adv Anat Pathol. 2017 Sep;24(5):268-277. doi: 10.1097/PAP.0000000000000151.
Hemosiderotic fibrolipomatous tumor is an unusual, distinctive soft tissue neoplasm with locally recurring potential, which most commonly occurs in the ankle and foot. Morphologic evidence strongly suggests that hemosiderotic fibrolipomatous tumor is related to another rare, locally aggressive tumor of the distal extremities, pleomorphic hyalinizing angiectatic tumor, with areas identical to hemosiderotic fibrolipomatous tumor seen at the periphery in most if not all pleomorphic hyalinizing angiectatic tumor. This morphologic evidence is further supported by molecular genetic data, showing recurrent TGFBR3 and/or MGEA5 rearrangements in both hemosiderotic fibrolipomatous tumor and pleomorphic hyalinizing angiectatic tumor. A possible link between hemosiderotic fibrolipomatous tumor and yet another low-grade sarcoma of the distal extremities, myxoinflammatory fibroblastic sarcoma, has also been suggested based on the occurrence of unusual examples of hemosiderotic fibrolipomatous tumor showing progression to myxoid sarcoma, demonstrating some but not all features of myxoinflammatory fibroblastic sarcoma. These "hybrid hemosiderotic fibrolipomatous tumor-myxoinflammatory fibroblastic sarcoma" also commonly show TGFBR3 and/or MGEA5 rearrangements. However, classic myxoinflammatory fibroblastic sarcoma lacks areas resembling hemosiderotic fibrolipomatous tumor, and shows a very low frequency of TGFBR3 and/or MGEA5 rearrangements in prospectively diagnosed cases. This suggests that so-called "hybrid hemosiderotic fibrolipomatous tumor-myxoinflammatory fibroblastic sarcoma" represents a form of malignant progression within hemosiderotic fibrolipomatous tumor, rather than a lesion strictly related to classic myxoinflammatory fibroblastic sarcoma. This article will review the morphologic features, genetic features, and differential diagnosis of these rare neoplasms, and discuss their interrelation, or lack thereof.
含铁血黄素纤维性脂肪瘤样肿瘤是一种不常见的、具有特征性的软组织肿瘤，具有局部复发的潜力，最常发生在踝关节和足部。形态学证据强烈表明，含铁血黄素纤维性脂肪瘤样肿瘤与另一种罕见的、具有局部侵袭性的四肢远端肿瘤——多形性透明细胞血管扩张性肿瘤有关，在大多数（如果不是全部）多形性透明细胞血管扩张性肿瘤中，肿瘤边缘可见与含铁血黄素纤维性脂肪瘤样肿瘤相同的区域。这种形态学证据进一步得到分子遗传学数据的支持，显示含铁血黄素纤维性脂肪瘤样肿瘤和多形性透明细胞血管扩张性肿瘤均存在 TGFBR3 和/或 MGEA5 重排。基于罕见的含铁血黄素纤维性脂肪瘤样肿瘤向黏液样肉瘤进展的病例，也提示了含铁血黄素纤维性脂肪瘤样肿瘤与另一种四肢低度恶性肉瘤——黏液炎症性纤维母细胞肉瘤之间可能存在联系，这些“杂交性含铁血黄素纤维性脂肪瘤样肿瘤-黏液炎症性纤维母细胞肉瘤”也常显示 TGFBR3 和/或 MGEA5 重排。然而，经典的黏液炎症性纤维母细胞肉瘤缺乏类似于含铁血黄素纤维性脂肪瘤样肿瘤的区域，且在前瞻性诊断的病例中 TGFBR3 和/或 MGEA5 重排的频率非常低。这表明所谓的“杂交性含铁血黄素纤维性脂肪瘤样肿瘤-黏液炎症性纤维母细胞肉瘤”代表了含铁血黄素纤维性脂肪瘤样肿瘤恶性进展的一种形式，而不是与经典的黏液炎症性纤维母细胞肉瘤严格相关的病变。本文将回顾这些罕见肿瘤的形态学特征、遗传学特征和鉴别诊断，并讨论它们之间的相互关系或缺乏相互关系。
