Abstract
Lipoblastoma-like tumor of the vulva (LLTV) is an exceptionally rare adipocytic mesenchymal tumor with only 4 cases reported previously. The aim of this study is to help characterize this tumor type. Eight cases of LLTV were identified in the consult files of one of the authors (C.D.M.F.). Clinical data and follow-up information were obtained from the referring pathologists. Detailed clinical information is available in all 8 cases. Patient age ranged from 17 to 46 years (median 27 y). Lesions presented as a vulvar mass with a variable growth rate, sometimes being painful. The most common preoperative clinical diagnosis was a Bartholin gland abnormality (4). The size of the mass ranged from 3.5 to 15 cm (median 5.6 cm). The lesions were described as grossly myxoid, mucoid, or gelatinous (4), well defined (4), and lobulated (3). None of the lesions exhibited necrosis. Histologically, LLTVs were lobulated and composed of variable proportions of mature adipocytes, bland univacuolated and bivacuolated lipoblasts, and spindle cells with short stubby nuclei in a diffusely myxoid background with prominent branching vessels. Nuclear atypia was minimal. No necrosis and only rare mitotic activity was identified. Only 1 of 7 tumors (in a 26-y-old patient) was positive for PLAG1 and retinoblastoma (Rb). Rb was lost, and PLAG1 was not expressed in all other tumors. HMGA2 was negative in 6 of 6 cases tested. Tumors were negative for S100 (5/5), MDM2, and CDK4 (5/6; 1 with just scattered cells positive for both antibodies). Two of 5 cases were positive for CD34. Fluorescence in situ hybridization for DDIT3 gene rearrangement was negative in 5 cases tested. The follow-up interval ranged from 4 months to 11 years (median 2.75 y). Three patients developed 1 local recurrence, 7 months, 2 years, and 8 years, respectively, after excision of the primary tumor. None of the patients has developed metastatic disease. LLTVs are indolent adipocytic mesenchymal tumors arising in adults. Lack of PLAG1 and HMGA2 expression in the majority of LLTV suggests that these lesions are distinct from "true" lipoblastoma. The loss of Rb in the majority of cases suggests a possible role of 13q chromosomal alterations and a possible relationship with the spindle cell lipoma tumor family.
摘要
外阴脂肪母细胞瘤样肿瘤(LLTV)是一种相当罕见的脂肪细胞源性间叶性肿瘤,只有4例报道。本研究旨在帮助识别该肿瘤类型,有8例LLTV经作者之一(C.D.M.F.)会诊证实。其临床资料及随访情况由请求会诊的病理医生提供。
所有8例LLTV临床资料详细。病人年龄17—46岁(中位数27岁)。病变表现为外阴肿块,生长速度不一,有时有疼痛感。最常见的临床术前诊断是前庭大腺异常(4例)。肿块大小3.5—15厘米(平均5.6厘米)。病变呈显著黏液样或胶样(4例),边界清楚(4例),分叶状(3例)。8例无一坏死。组织病理:LLTV呈分叶状,由比例不一的成熟脂肪细胞、温和的单空泡及双空泡的脂肪母细胞、具短钝状细胞核的梭形细胞组成,分布于有显著分支状血管的弥漫黏液背景中。核的非典型性轻微。无坏死,偶见核分裂象。7例中有1例(病人26岁)肿瘤的PLAG1和Rb(retinoblastoma)阳性,其余肿瘤中Rb丢失,PLAG1不表达。有6例检测了HMGA2,皆阴性。肿瘤中S-100阴性(5/5),MDM2和CDK4阴性(5/6),有1例的MDM2和CDK4抗体散在细胞阳性。CD34在5例中有2例阳性。用FISH检测5例DDIT3基因重排,皆阴性。随访时间4个月到11年(平均2.75年)。三例局部复发,时间分别为原发肿瘤切除后7个月、2年和8年。无1例发生转移。
LLTV是一种发生于成人的、呈惰性的脂肪细胞源性间叶性肿瘤,其中多数缺乏PLAG1和HMGA2的表达,提示该病变不同于真正的脂肪母细胞瘤。大多数病例Rb丢失,提示13q染色体易位的可能性及其与梭形细胞脂肪瘤家族存在相互联系的可能性。
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