不同的作者最近描述了一种以脂肪细胞大小变化为特征的脂肪瘤亚型。单细胞脂肪坏死,和一个极小到轻度核异型的子集,并将其称为非等轴细胞/异型增生性脂肪瘤(AC/DL)。这些脂肪瘤遵循良性过程,很少复发。在3个例子中,AC/DL发生在儿童视网膜母细胞瘤(RB)患者中。我们报告了另一个这样的例子,其中一名30岁男性的颈部和背部发生了多个AC/DL,该男性在婴儿期有种系RB1基因缺失和双侧RB。切除时,所有肿瘤在组织学上都显示相似的脂肪细胞形态,局灶性单细胞坏死,周围有双核或多核组织细胞,超色和最低限度的非典型脂肪细胞核,空泡化的Lockhern改变,纤维粘液样病变的罕见病灶,偶有毛细血管周围的单核细胞簇,和RB1免疫染色的损失。不明确的非典型细胞,成脂细胞,没有小花有核或多核的巨细胞。肿瘤细胞的分子分析显示单等位基因RB1基因丢失,没有MDM2和CDK4基因的扩增。短期随访未显示肿瘤复发。RB幸存者的AC/DL具有多重性,统一组织学,良性过程。他们的生物学似乎与普通脂肪瘤不同,梭形细胞脂肪瘤,和不典型的脂肪瘤。
Different authors have recently described a subtype of lipoma characterized by variation of adipocyte size, single cell fat necrosis, and a subset with minimal to mild nuclear atypia, and termed these as anisometric cell/dysplastic lipoma (AC/DL). These lipomas follow a benign course and rarely recur. In 3 examples, AC/DL has occurred in patients with childhood retinoblastoma (RB). We report another such example where multiple AC/DL occurred in the neck and back of a 30-year-old male who had germline RB1 gene deletion and bilateral RB in infancy. On excision, all tumors histologically showed similar morphology of adipocyte anisometry, focal single cell necrosis with surrounding binucleated or multinucleated histiocytes, hyperchromatic and minimally atypical lipocyte nuclei, vacuolated Lockhern change, rare foci of fibromyxoid change, occasional mononuclear cell clusters around capillaries, and loss of RB1 immunostaining. Unequivocal atypical cells, lipoblasts, floret-nucleated or multinucleated giant cells were absent. Molecular analysis of tumor cells showed monoallelic RB1 gene loss without amplification of MDM2 and CDK4 genes. Short-term follow up did not show tumor recurrence. AC/DLs in RB survivors are characterized by multiplicity, unifying histology, and benign course. Their biology appears distinct from ordinary lipomas, spindle cell lipomas, and atypical lipomatous tumors.