Liposarcomas with Mixed Well-Differentiated and Pleomorphic Features – A Clinicopathologic Study of 8 Cases

JM Boland, SW Weiss, AM Oliveira, ML Erickson-Johnson, AL Folpe. Mayo Clinic, Rochester, MN; Emory University, Atlanta, GA.

Background: Pleomorphic liposarcoma (PL) is defined as an undifferentiated pleomorphic sarcoma containing a variable number of pleomorphic lipoblasts. It is considered a distinct high grade sarcoma unrelated to other forms of liposarcoma since it almost always arises de novo without an associated low grade precursor lesions (e.g. well differentiatied liposarcoma (WDL)) and rarely co-exists with other liposarcoma patterns. We have, however, observed a small number of cases of PL which arose in association with WDL and have studied these cases to define their clinico-pathologic features and their nosologic relationship to other forms of liposarcoma.

Design: Cases showing the presence of both PL and WDL were retrieved from our consultation archives. The tumors were characterized at the molecular cytogenetic level for the presence of MDM2/CPM amplification when archival tumor blocks were available. One hundred cells were scored in each instance by two independent investigators. Follow-up information was obtained from the referring clinicians.

Results: Eight tumors were identified, occurring in 4 men and 4 women (mean age 55 years, range 35-78 years). Sites of origin included the retroperitoneum (3), scrotum (2), buttock (2), and abdominal cavity (1). Tumors consisted predominantly of typical WDL, with an “abrupt” transition to pleomorphic spindle cell sarcoma containing pleomorphic lipoblasts. MDM2/CPM amplification was present in 4 of 6 (66%) cases, all of which consisted chiefly of PL in the studied blocks. Clinical follow-up (6 of 8 (75%) patients; range 7-29 months; median 19 months) showed 5 patients alive without disease and 1 dead of disease.

Conclusions: PL with WDL is a rare pattern in liposarcoma. In the past such tumors were considered liposarcomas of mixed type to imply two distinct forms of liposarcoma occurring in the same lesion. The presence of MDM2/CPM amplification in the PL component of mixed WDL/PL suggest that a subset of PL may arise through tumor progression of WDL or may represent a “transitional” or partially differentiated step toward a classic DL. On-going review of a large cohort of tumors previously diagnosed as “DL” and additional molecular genetic study of both WDL and PL zones should clarify the relationship of these unusual tumors to classical DL, a tumor which by definition does not show lipoblastic differentiation.

成人型纤维肉瘤（RS）：一个研究结构48年期间154例有争议病例的重新评价
A Bahrami, AL Folpe. Mayo Clinic, Rochester, MN.
Background: Adult FS, defined by the WHO as a “malignant tumor, composed of fibroblasts… and, in classical cases, a herringbone architecture” was once considered the most common adult sarcoma. Currently FS is regarded as a diagnosis of exclusion, representing only 1-3% of adult sarcomas. This trend is likely due to: 1) widespread use of immunohistochemistry (IHC) and molecular diagnostic techniques, 2) recognition of distinct FS subtypes, and 3) distinction of FS from undifferentiated pleomorphic sarcoma (UDPS). However, no recent series has critically re-evaluated putative FS, to estimate their true incidence.

背景：成人型FS，WHO定义为“由纤维母细胞组成的恶性肿瘤…，经典型病例呈鱼骨样结构”曾被认为是最常见的发生于成人的肉瘤。目前FS是作为一种排除性诊断，仅占成人肉瘤的1-3%。这种趋势可能是由于1）免疫组化和分子诊断技术的广泛应用，2）独特的FS亚型的确认和3）FS与未分化多形性肉瘤（UDPS）的区分。然而，近来没有系列研究对有争议的FS进行严格的重新评价而评估其真正的发生率。
Design: 178 cases diagnosed as adult FS in soft tissue locations were retrieved from
our institutional archives for the period 1960-2008. 24 cases with insufficient material were excluded. Based on the morphology of the final 154 cases, IHC was performed using some combination of: wide-spectrum CK, EMA, high molecular weight CK, S100, Melan A, HMB-45, CD34, CD31, TLE1, smooth muscle actin, desmin, Myo-D1, myogenin, c-kit, INI1, calretinin, WT1 and TTF1. Revised diagnoses were based on clinical, morphological, and IHC findings.

设计：收集我们研究结构在1960-2008年间诊断的软组织部位的成人FS178例。24例因标本量不足而除去。根据最后的154例病例形态学，我们使用了下面一组免疫标记：光谱CK、EMA、HMW-CK、S100、, Melan A、HMB-45、CD34、CD31、TLE1、SMA、desmin、Myo-D1、myogenin、c-kit、IN1、calretinin、WT1和TTF1。根据临床、形态学和IHC结果对原来的诊断进行了修改。
Results: The original group of putative FS occurred in 81 M and 73 F (median 53 years, range 2-99 years), and involved the legs (50 cases), head/neck (30 cases), thorax/abdomen (22 cases), arms (21 cases), mediastinum (8 cases), abdomen/ retroperitoneum/pelvis (13 cases), and lung (10 cases). Only 22 cases met WHO criteria for FS. These occurred in 13 M and 9 F (median 49 years, range 6-74 years), and involved the legs (11 cases), head/neck (6 cases), thorax/abdomen (2 cases) mediastinum (2 cases), and arm(1 case). Non-FS (132 cases) were reclassified as: UDPS (38 cases), synovial sarcoma(21 cases), SFT (14 cases), myxo-FS (10 cases), MPNST (6 cases), DFSP, desmoplastic melanoma (4 cases each), LG fibromyxoid sarcoma, sarcomatoid CA, desmoid, RMS, myofibroblastic sarcoma, spindle cell liposarcoma (3 cases each), sclerosing epithelioid FS, fibroma-like epithelioid sarcoma, leiomyosarcoma, cellular fibrous histiocytoma (2 cases each), and other (9 cases).

结果：原来诊断的FS男性81例，女性73例（发病年龄2-99岁，平均年龄53岁），发病部位分别为腿部（50例）、头/颈部（30例）、胸/腹腔（22例）、胳膊（21例）、纵膈（8例）、腹部/后腹膜/盆腔（13例）和肺（10例）。仅有22例符合WHO FS诊断标准。男性13例，女性9例（发病年龄6-74岁，平均49岁）。发生部位分别为腿部（11例）、头/颈部（6例）、胸/腹腔（2例）、纵膈（2例）和胳膊（1例）。132例非纤维肉瘤被重新分类为未分化多形性肉瘤（28例）、滑膜肉瘤（21例）、SFT（14例）、粘液性纤维肉瘤（10例）、MPNST（6例）、DFSP和促纤维增生性黑色素瘤（各4例），低级别纤维黏液样肉瘤、肉瘤样癌、硬纤维瘤、横纹肌肉瘤、肌纤维母细胞肉瘤、梭形细胞脂肪肉瘤（各3例），硬化性上皮样纤维肉瘤、纤维瘤样上皮样肉瘤、平滑肌肉瘤、富于细胞性纤维组织细胞瘤（各2例）以及其他肿瘤（9例）。

Conclusions: Using modern diagnostic criteria and ancillary IHC we have been able to reclassify 87% of putative FS. Exclusive of UDPS, the distinction of which from FS is subjective, 61% of putative FS were reclassified, most commonly as monophasic synovial sarcoma and solitary fibrous tumor. We conclude that true FS is exceedingly rare, accounting for <0.1% of &#8764;18,000 adult soft tissue sarcomas seen at our institution during this time period, and should be diagnosed with great caution

结论：使用现代诊断标准和免疫组化辅助技术，我们能对87%有争议饿FS重新分类。除了与未分化多形性肉瘤的区分是主观外，61%有争议的FS被重新分类，其中最常见为单向性滑膜肉瘤和孤立性纤维性肿瘤。我们认为真正的FS非常罕见，在此段时间内我们单位诊断的18,000成人软组织肉瘤的<0.1%。诊断FS应特别谨慎。

A Pro-Inflammatory Tumor Microenvironment with High Chemokine Expression and High Tumor-Infiltrating CD3+CD8+ Numbers Associates with Improved Survival in Ewing Sarcoma (EWS)

D Berghuis, SJ Santos, JJ Baelde, AHM Taminiau, RM Egeler, MW Schilham, PCW

Hogendoorn, AC Lankester. Leiden University Medical Center, Leiden, Netherlands.

Background: Despite multimodal therapy, patients with advanced-stage EWS have a poor prognosis. Immunotherapeutic strategies may provide novel treatment modalities. Although EWS cells can be recognized and targeted by T and NK cells in vitro, limited information is available about tumor-immune interactions within the tumor microenvironment. Here we investigate characteristics of the immune cell infiltrate and chemokine expression in EWS, as well as their mutual relationship and correlations with clinicopathological parameters.

Design: EWS tumors (n=20) were evaluated by quadruple immunohistochemistry for presence and spatial distribution of tumor-infiltrating lymphocytes (TIL; CD3+/CD4+/ CD8+). Chemokine expression was analyzed in both tumors and cell lines (n=9) by qRT-PCR, immunohistochemistry and flow cytometry.

Results: Substantial inter-tumor variations were observed for both numbers and distribution (tumor- or stroma-infiltrating) of TIL as well as for chemokine expression profiles. Tumor-infiltrating T-cells contained higher percentages of CD3+CD8+ cells as compared to stroma-infiltrating cells (p=0.04). Moreover, survival analysis revealed prognostic benefit of a more robust CD3+CD8+ T-lymphocytic infiltrate (p=0.04). Positive correlations between gene expression levels of several functionally related, proinflammatory chemokines (mainly CCR5-/ CXCR3-ligands) and TIL numbers (p<0.05) suggested that expression of these chemokines contributed to TIL recruitment. The presence of both constitutive and IFNã-inducible expression of several pro-inflammatory chemokines (CCL5, CXCL9, CXCL10) was confirmed at protein level. High chemokine expression levels, like the presence of high tumor-infiltrating CD3+CD8+ cell numbers, associated with improved overall survival (p=0.03).

Conclusions: These results demonstrate prognostic benefit of a tumor microenvironment with high levels of pro-inflammatory chemokines as well as high numbers of tumorinfiltrating CD3+CD8+ T-lymphocytes and point to a role for adaptive anti-tumor immune responses in prevention of tumor progression.

Chondroblastoma-Like Osteosarcoma: A Clinicopathologic Review of 17 Cases

A Bahrami, K Unni, F Bertoni, P Bacchini, H Dorfman, T Nojima, C Inwards. Mayo

Clinic, Rochester; Casa di Cura Villa Erbosa, Bologna, Italy; Montefiore Medical Center, New York; Kanazawa Medical University, Uchinada, Japan.

Background: Chondroblastoma-like osteosarcoma (CBL-like OS) is an exceedingly rare histologic variant of OS that morphologically simulates CBL. Although this subtype is recognized in the WHO classification of bone tumors and bone pathology textbooks, there are only two documented cases in the literature.

Design: We conducted a clinicopathologic and radiographic review of 17 cases collected from 3 large consultative practices of OS showing histologic features resembling CBL. Histologic sections from the primary tumor (all cases) and pulmonary metastases (2 cases) were reviewed. Radiographic information was available on 13 cases.

Results: The tumors occurred in 9 M and 8 F with a median age of 35 years (range, 13-72 years), and involved the following bones: metatarsus (3 cases); femur (3 cases); rib (3 cases); humerus (2 cases); and talus, phalanx, tibia, fibula, ischium and ilium (1 each). In the long bones, tumors arose in the meta-diaphysis (6 cases) and epiphysis (1 case). The constant histologic feature that simulated CBL was the diffuse growth of monotonous, minimally to moderately atypical rounded cells with ovoid nuclei. Cytologic atypia was more pronounced in recurrent tumors. The most helpful feature of malignancy was destructive permeation of host bone/soft tissue. The tumors also showed a variable pattern of abnormal bone production including diffuse sheets of dense osteoid, heavy irregular trabeculae of bone, and coarse or linear calcification of woven bone. The pulmonary metastases had histologic features of OS. 13 tumors had malignant or worrisome radiographic findings, and 1case was equivocal. Of patients with follow-up information, 6 developed one or more local recurrences, 2 developed pulmonary metastases, and 2 died of disease.

Conclusions: We confirmed a subtype of OS resembling CBL. In a tumor with cytologic features similar to CBL, histologic evidence of destructive growth and/or abnormal pattern of bone production should raise the possibility of CBL-like OS, particularly if the tumor is located in an unusual site for CBL or has radiographic findings suggesting malignancy

A Subset of PEComas Harbor TFE3 Gene Fusions

少数PEComas具有TFE3基因融合

Background: Perivascular epithelioid cell neoplasms (PEComas) include the common renal angiomyolipoma, pulmonary clear cell sugar tumor and lymphangioleiomyomatosis, and less common neoplasms of soft tissue, gynecologic and gastrointestinal tracts. Recently, aberrant immunoreactivity for TFE3 protein (a sensitive and specific marker of neoplasms harboring TFE3 gene fusions) has been reported in as many as 80% of PEComas. TFE3 gene status in these neoplasms has not been systematically investigated, though a recent case report has documented a PSF-TFE3 gene fusion in an extrarenal PEComa.

背景：血管周上皮样细胞肿瘤（PEComas）包括常见的肾血管肌脂肪瘤、肺透明细胞糖瘤和淋巴管肌瘤病，以及发生于软组织、妇科和胃肠道少见的肿瘤。最近有报道TFE3蛋白（TFE3基因融合的肿瘤一种敏感性和特异性标记物）可在80%PEComas中异常表达。尽管近来有PSF-TFE3基因融合的肾外PEComa的病例报道，但这些肿瘤中TFE3基因改变还未系统研究。

Design: We used a fluorescence in situ hybridization (FISH) break-apart assay to evaluate for TFE3 gene fusions in archival material from 26 PEComas. These cases included 2 previously published TFE3 immunoreactive non-renal PEComas, 12 additional non-renal PEComas (5 soft tissue, 4 abdominal, 2 uterine, 1 hepatic), and 12 renal angiomyolipomas with predominant spindle or epithelioid morphology. Results were correlated with TFE3 immunoreactivity and clinicopathologic features.

设计：我们使用FISH断裂法研究了26例PEComas中TFE3基因融合状况。这些病例中包括2例以前报道的TFE3阳性的肾外的PEComas，12例另外的非肾脏的PEComas（软组织5例、腹部4例、子宫2例和肝脏1例）和12例以梭形细胞或上皮样细胞形态为主的肾血管肌脂肪瘤。同时将FISH检测结果与TFE3免疫组化结果和临床病理特征进行分析。

Results: Three non-renal PEComas (mean patient age 19 years) demonstrated TFE3 gene fusions by FISH; all three demonstrated strong positive (3+) TFE3 immunoreactivity. Two of these cases had adequate mRNA for RT-PCR analysis, and neither harbored a PSF-TFE3 gene fusion. In addition, a metastasis of a uterine PEComa which showed moderate positive (2+) TFE3 immunoreactivity demonstrated TFE3 gene amplification, a previously unreported phenomenon. None of the other 22 PEComas (mean patient age 54 years) demonstrated TFE3 gene alterations, though 4 demonstrated moderate positive (2+) TFE3 immunoreactivity. All 4 PEComas with TFE3 alterations immunolabeled strongly for Cathepsin K, similar to other PEComas.

结果：3例非肾PEComas（平均年龄19岁）FISH检测证实有TFE3基因融合，且所有TFE3免疫组化均为强阳性（3+），其中2例有足够的mRNA可用以RT-PCR分析，但均未见PSF-TFE3基因融合。另外，转移性子宫PEComaTFE3免疫组化为中等阳性（2+），且有TFE3基因扩增，该现象以前未见报道。其他22例PEComas（平均54岁）中有4例TFE3免疫组化为中等阳性（2+），但均未见TFE3基因扩增。所有4例伴有TFE3改变的PEComas均强阳性表达Cathepsin K，与其他PEComas相同。

Conclusions: A subset of PEComas harbor TFE3 gene fusions. While numbers are small, distinctive features of these cases include young age, extrarenal location, absence of association with tuberous sclerosis (TS), predominant epithelioid clear cell morphology, minimal immunoreactivity for muscle markers, and strong (3+) TFE3 immunoreactivity. Despite significant morphologic overlap with other PEComas, PEComas harboring TFE3 gene fusions may represent a distinctive entity.

结论：有一些PEComas具有TFE3基因融合。虽然这部分病例数量少，但它们具有独特的临床病理特征如年轻、肾外发生，缺乏相关的结核性硬化症（TS）、主要以上皮样透明细胞形态，很少表达肌源性标记物和TFE3免疫组化强阳性（3+）等。虽然形态学上与其他PEComas有明显的重叠，但TFE3基因融合的PEComas可能为一种独特的疾病实体。

A Subset of PEComas Harbor TFE3 Gene Fusions

P Argani, P Illei, G Netto, J Ro, HY Cho, S Dogan, M Ladanyi, G Martignoni, S Aulmann,

SW Weiss. Johns Hopkins Medical Institutions, Baltimore, MD; Asan Medical Center, Seoul, Korea; Memorial Sloan-Kettering Cancer Center, New York, NY; University of Verona, Verona, Italy; University of Heidelberg, Heidelberg, Germany; Emory

University, Atlanta, GA.

Background: Perivascular epithelioid cell neoplasms (PEComas) include the common renal angiomyolipoma, pulmonary clear cell sugar tumor and lymphangioleiomyomatosis, and less common neoplasms of soft tissue, gynecologic and gastrointestinal tracts. Recently, aberrant immunoreactivity for TFE3 protein (a sensitive and specific marker of neoplasms harboring TFE3 gene fusions) has been reported in as many as 80% of PEComas. TFE3 gene status in these neoplasms has not been systematically investigated, though a recent case report has documented a PSF-TFE3 gene fusion in an extrarenal PEComa.

Design: We used a fluorescence in situ hybridization (FISH) break-apart assay to evaluate for TFE3 gene fusions in archival material from 26 PEComas. These cases included 2 previously published TFE3 immunoreactive non-renal PEComas, 12 additional non-renal PEComas (5 soft tissue, 4 abdominal, 2 uterine, 1 hepatic), and 12 renal angiomyolipomas with predominant spindle or epithelioid morphology. Results were correlated with TFE3 immunoreactivity and clinicopathologic features.

Results: Three non-renal PEComas (mean patient age 19 years) demonstrated TFE3 gene fusions by FISH; all three demonstrated strong positive (3+) TFE3 immunoreactivity. Two of these cases had adequate mRNA for RT-PCR analysis, and neither harbored a PSF-TFE3 gene fusion. In addition, a metastasis of a uterine PEComa which showed moderate positive (2+) TFE3 immunoreactivity demonstrated TFE3 gene amplification, a previously unreported phenomenon. None of the other 22 PEComas (mean patient age 54 years) demonstrated TFE3 gene alterations, though 4 demonstrated moderate positive

(2+) TFE3 immunoreactivity. All 4 PEComas with TFE3 alterations immunolabeled strongly for Cathepsin K, similar to other PEComas.

Conclusions: A subset of PEComas harbor TFE3 gene fusions. While numbers are small, distinctive features of these cases include young age, extrarenal location, absence of association with tuberous sclerosis (TS), predominant epithelioid clear cell morphology, minimal immunoreactivity for muscle markers, and strong (3+) TFE3 immunoreactivity. Despite significant morphologic overlap with other PEComas, PEComas harboring TFE3 gene fusions may represent a distinctive entity.