Dedifferentiated liposarcoma of the cheek

Liposarcomas of the head and neck region are rare; only a few cases have been reported to arise in the cheek or buccal mucosa. Dedifferentiated liposarcoma has rarely been reported in the head and neck region and, to the best of our knowledge, this is the first reported case of dedifferentiated liposarcoma of the cheek. Dedifferentiated liposarcoma is a mixed histologic subtype defined by the association of an atypical lipomatous tumor or well-differentiated liposarcoma and a nonlipogenic sarcoma. The patient was a 61-year-old man who presented with a soft-tissue mass of the left cheek and a presumptive diagnosis of salivary neoplasm based on a fine needle aspiration. The tumor was excised and consisted histologically of an atypical lipomatous tumor/well-differentiated liposarcoma composed a well-differentiated lipomatous neoplasm with atypical cells and rare lipoblasts. The tumor recurred in the same location 5 months after surgery. The recurrent tumor was primarily composed of a nonlipogenic spindle sarcoma with focal rhabdomyoblastic differentiation associated with areas of an atypical lipomatous tumor/well-differentiated liposarcoma.     

Dedifferentiated liposarcoma with rhabdomyoblastic differentiation

Dedifferentiated areas of dedifferentiated liposarcoma (DDL) usually show malignant fibrous histiocytoma (MFH)- or fibrosarcoma-like features and lack any histologic signs of specific differentiation. However, some reports have demonstrated specific differentiation in these areas, with histologic features resembling those of rhabdomyosarcoma, leiomyosarcoma, and osteosarcoma. We report here a pathologic and genetic analysis of three cases of DDLs with rhabdomyosarcomatous areas. MFH- or fibrosarcoma-like areas of one primary DDL and two recurrent DDLs contained various amounts of rhabdomyoblasts, which were immunoreactive for desmin, myoglobin, muscle actin (HHF-35), and myogenin. An ultrastructural examination demonstrated rhabdomyoblasts with abundant cytoplasm containing thin and thick filaments and Z-bands. By real-time PCR, amplification of mdm2 and cdk4 was confirmed in both well-differentiated and dedifferentiated areas with rhabdomyoblasts of all cases. To our knowledge, only seven cases of DDLs with rhabdomyosarcomatous components have been reported, and furthermore, the genetic profiles of the rhabdomyosarcomatous components in DDLs have not been investigated. This study demonstrates that DDLs with rhabdomyosarcomatous areas have genetic alterations that are common to well-differentiated/dedifferentiated liposarcomas.     

伴脑膜上皮样旋涡的去分化脂肪肉瘤一例

患者男,56岁。因阵发性左下腹疼痛半个月,于2004年6月11日入院。体检：腹部稍丰满,可扪及包块位于左下及右上腹部,质硬,轻压痛,不活动,表面尚光滑。CT示：腹部巨大包块(畸胎瘤可能性大)。发现包块3d后进行手术,术中见包块位于小肠系膜,与周围无粘连。     

Dedifferentiated liposarcoma presenting as jejunal polyp. Case report

We report a case of primary jejunal dedifferentiated liposarcoma presenting as a submucosal polyp mimicking a benign neoplasm. This is an extremely rare presentation. The histological feature of interest was the spindle cell lipoma-like appearance of the well-differentiated component. The use of MDM2 immunostaining in differentiating benign lipomatous tumours from well-differentiated liposarcomas is mentioned, which is of value especially in lipomatous tumours of the gut where ulcerated benign tumours can show varying degrees of atypia.     

Dedifferentiated liposarcoma with extensive lymphoid component

An unusual variant of dedifferentiated liposarcoma with extensive lymphocytic component is described. A 71-year-old patient suffered from a relapse of an atypical lipomatous tumor/well-differentiated liposarcoma with early micronodular (low-grade) dedifferentiation, which had been resected 4 years before. The relapse revealed features of a dedifferentiated liposarcoma with spindle-cell, partly pleomorphic dedifferentiation and osseous metaplasia. Clearly separated from the spindle-cell areas, an extensive homogeneously dense lymphoid (lymphocytic) tumor-component was evident, with relative abrupt transition to the well-differentiated liposarcoma component. Using immunohistochemistry and PCR, the lymphoid ("lymphoma-like") infiltrate proved to be a polyclonal lymphocytic proliferation. Fluorescence in situ hybridization (FISII) analysis revealed no signs of MDM2- and CDK4-gene amplification in the lymphoid areas, although within this mononuclear lymphoid population, large polymorphic nuclei displayed an amplified number of MDM2/CDK4 gene copies, indicating the presence of truly dedifferentiated tumor cells within the lymphoid component. The results favor a reactive lymphocytic infiltration versus a neoplastic one, which might be caused for example by chemoattractive agents. An extensive lymphoid "overgrowth" must be considered within the spectrum of unusual variants and in the differential diagnosis of dedifferentiated liposarcoma.     

Dedifferentiated liposarcoma with chondroblastic osteosarcomatous dedifferentiation

We describe a rare case of dedifferentiated liposarcoma with features resembling chondroblastic osteosarcoma in the dedifferentiated component. The tumor was removed from the left thigh in a 78-year-old male. It consisted of a well-differentiated liposarcoma and an anaplastic component that contained numerous osteoid and cartilaginous tissues surrounded by high-grade spindle cell sarcoma. To our knowledge, only two cases similar to the divergent chondroblastic osteosarcomatous dedifferentiation of this disease have been reported in the literature.     

去分化脂肪肉瘤28例临床病理分析

目的 探讨去分化脂肪肉瘤(dedifferentiated liposarcoma,DL)中去分化成分的形态学特征.方法 用常规HE染色和免疫组织化学方法,对28例DL进行观察分析.结果 在28例DL中,25例由非典型脂肪瘤样肿瘤/高分化脂肪肉瘤和非脂肪性梭形细胞肉瘤组成;1例为黏液样脂肪肉瘤和非脂肪性梭形细胞肉瘤组成;2例复发性病例未见到高分化脂肪肉瘤成分,均为非脂肪性梭形细胞肉瘤成分.免疫组化:28例中有14例行免疫组化染色,脂肪肉瘤区域脂母细胞S-100蛋白(+),部分脂肪肉瘤中的梭形细胞CD34(+).14例DL中去分化成分3例SMA和HHF35(+),1例desmin和HHF35(+),CD34、CD117、S-100、CD99、AACT、HMB-45、CK、CR均(-),CD68部分病例散在(+).通过对DL的形态学观察发现,去分化区域可以单独或混合呈现以下形态结构:(1)多形性恶性纤维组织细胞瘤样,(2)纤维肉瘤样,(3)低度恶性黏液纤维肉瘤样,(4)纤维瘤病样,(5)平滑肌肉瘤样,(6)脑膜瘤样漩涡结构,(7)横纹肌肉瘤分化,(8)骨/软骨分化,(9)炎性肌纤维母细胞瘤样,(10)血管外皮瘤样等.其中炎性肌纤维母细胞瘤样和血管外皮瘤样结构文献中尚未见报道.结论 DL中去分化成分最常见的结构是高级别肉瘤形态,但也可以是低度恶性黏液纤维肉瘤样、纤维瘤病样、炎性肌纤维母细胞瘤样、血管外皮瘤样等低级别肉瘤形态.可以是单一分化,也可以向平滑肌、横纹肌、骨/软骨等异源性分化.     

Dedifferentiated liposarcoma of the oral cavity with angiosarcomatous dedifferentiation

We report a unique case of a 42-year-old woman with a dedifferentiated liposarcoma of the soft tissue of the oral cavity with angiosarcomatous dedifferentiation. Liposarcomas compromising the head and neck region are very unusual, and most of the cases in oral cavity show a well-differentiated pattern. Dedifferentiation in liposarcomas occurs in about 10% of the cases and, when it occurs, the dedifferentiated areas usually resemble high-grade fibrosarcoma or pleomorphic sarcoma. Divergent differentiation might also occur. To the best of our knowledge, there are only nine cases of dedifferentiated liposarcoma of the oral cavity, none of which show an angiosarcomatous dedifferentiation.     

伴脑膜上皮样旋涡和骨化的去分化脂肪肉瘤

目的：探讨伴脑膜上皮样漩涡和骨化的去分化脂肪肉瘤的形态特点,方法：应用常规病理和免疫组化对1例伴脑膜上皮样旋涡和骨化的去分化脂肪肉瘤进行临床病理分析并复习相关文献。结果：肿块位于后腹膜,直径17cm,包膜不完整,切面灰白色,肿瘤中大量梭形细胞排列成多个脑膜瘤样漩涡,有明显的纤维化,淋巴细胞浸润和出血,邻近漩涡处见成熟的骨小梁形成;肿瘤内见分化良好的硬化性脂肪肉瘤区域,同时伴有认性纤维肉瘤区域,漩涡与硬化性脂肪肉瘤区域,硬化性脂肪肉瘤与黏液性纤维肉瘤区域二者之间界限清楚,呈突然转变之势,结论：去分化脂肪肉瘤伴脑膜上皮样漩涡和骨形成是十分罕见的,脑膜上皮样漩涡 的组织可能来源于类似周细胞或肌纤维母细胞的间叶细胞。     

Dedifferentiated liposarcoma with peculiar meningothelial-like whorling and metaplastic bone formation

Dedifferentiated liposarcoma with peculiar meningothelial-like whorling pattern and metaplastic bone formation (DDLMB) is an unusual morphologic entity that is characterized by an atypical lipomatous tumor/well-differentiated liposarcoma with epithelioid or spindle cells concentrically arranged into meningothelial-like “whorls,” and mature bone trabeculae rimmed by reactive osteoblasts. We recently experienced 2 cases of DDLMB, one in a 64-year–old male patient with a painless right groin mass and another in a 42-year–old female patient with a painless right abdominal mass. The size of the tumors was 3.5 and 18 cm; and the tumors were located in the right scrotal sac and retroperitoneum in case 1 and case 2, respectively. Under the initial clinical diagnosis of cord lipoma in case 1 and high-grade sarcoma in case 2, the masses were removed. The cut surfaces of the masses were well circumscribed with encapsulation, red-tan, firm, and multinodular. Microscopically, the tumors consisted of atypical lipomatous tumor/well-differentiated liposarcoma with meningothelial-like whorls and metaplastic bone formation in both cases. In addition, the first case showed focal areas of paraganglioma-like pattern; and the second case showed pleomorphic high-grade sarcoma with low-grade myxofibrosarcoma-like areas. Immunohistochemically, the tumor components with meningothelial-like pattern and paraganglioma-like pattern in DDLMB were positive for vimentin and CD56 and negative for pancytokeratin, epithelial membrane antigen (EMA), desmin, and smooth muscle actin. Characteristically, the paraganglioma-like area was immunoreactive for S-100 protein, with a “dot-like” staining pattern. The patient additionally underwent radical orchiectomy in case 1. Review of the literature revealed that only 34 cases of DDLMB have been reported. One case of dedifferentiated liposarcoma with a predominant paraganglioma-like pattern has also been reported in the literature. To our knowledge, case 1 represents the first report of DDLMB with paraganglioma-like pattern. A brief literature review was made with focus on the morphologic variations of DDLMB.     

Dedifferentiated myxoid liposarcoma: a clinicopathological study suggesting a closer relationship between myxoid and well-differentiated liposarcoma

Myxoid/round cell liposarcoma is arguably the commonest type of liposarcoma occurring in the extremities and may show gradual progression from low-grade, pure myxoid liposarcoma to high-grade round cell liposarcoma. Rarely myxoid/round cell liposarcoma is associated with areas of well-differentiated or pleomorphic liposarcoma (mixed liposarcoma). We describe the clinicopathological features of three unusual myxoid/round cell liposarcomas which showed morphological features of de novo dedifferentiation. All patients were male and were aged 66, 70 and 76 years, respectively. One lesion each arose in the retroperitoneum, inguinal region and peritoneal cavity. Histologically, in one case the myxoid/round cell component was juxtaposed to a high-grade non-lipogenic component resembling non-pleomorphic storiform 'malignant fibrous histiocytoma' ('MFH'), one case showed a combination of myxoid liposarcoma and a high-grade myxofibrosarcoma-like component (so-called myxoid 'MFH'), and in the third case, a well-differentiated myxoid liposarcoma with a discontinuous micronodular pattern of dedifferentiation was seen. Follow-up information of 30, 28 and 26 months revealed two recurrences each in two patients. These patients died of postoperative pulmonary embolism and abdominal haemorrhage, respectively; systemic metastases were not noted. These cases demonstrate that myxoid/round cell liposarcoma can show, albeit very rarely, histological features of dedifferentiation. Cases like these, combined with the occurrence of mixed-type liposarcoma (well-differentiated/myxoid liposarcoma) and the vicinity of chromosomal regions involved by specific karyotypic aberrations in these tumours, suggest that myxoid/round cell liposarcoma and well-differentiated liposarcoma (including its dedifferentiated variant) are more closely related in biological terms than is generally believed.     

Dedifferentiated liposarcoma with an inflammatory malignant fibrous histiocytoma-like component presenting a leukemoid reaction

A rare case of dedifferentiated llposarcoma (well-differentiated llposarcoma with an inflammatory mallgnant fibrous histiocytoma (MFH)-like anaplastlc component) occurrtng in a 69-year-old male is presented. The patient had noticed a dull pain in his left loin and thigh for about 1 month. Computed tomography examination revealed a low-density mass lesion, measuring about 6 cm In diameter, in the left lliopsoas muscie, and It was surgically removed. Grossly, the lesion was composed of an encapsulated, soft, whitish mass and an adjacent, well-demarcated, yellowish hard nodule, measuring about 2.5 cm In diameter. Microscopically, both lesions showed features of an inflammatory variant of MFH and a sclerosing type of well-differentiated liposarcoma, respectively. To our knowledge, only two cases of dedifferentiated liposarcoma combined with inflammatory MFH as a dedifferentiated component have been recorded in the literature. The salient feature of the present case is a systemic inflammatory reaction, as shown by prominent leukocytosis (up to 73 900/mm³) and the elevated serum value of C reactive protein (up to 26.0 mg/dL), which were transiently reduced after surgery. The Inflammatory reaction was suggested to be induced by cytokines, such as granulocyte colony-stimulating factor and interleukin-6, which were probably produced by the tumor cells in the present case, because the elevated serum values of those cytokines were decreased after surgery.     

Dedifferentiated liposarcoma of the pyriform sinus: report of a case and review of the literature

Laryngeal and hypopharyngeal liposarcomas are extraordinarily infrequent tumors. To the best of our knowledge there are fewer than 40 well-documented cases reported to date. Almost all of them are well-differentiated liposarcomas, with only 2 laryngeal-hypopharyngeal dedifferentiated liposarcomas. Dedifferentiated liposarcoma is defined as a well-differentiated liposarcoma with areas of high-grade spindle cell nonlipogenic sarcoma. The well-differentiated areas may be of a lipoma-like, sclerosing, or mixed type, and the dedifferentiated areas most frequently are of malignant fibrous hystiocytoma-like type. Despite its commonly pleomorphic histology, dedifferentiated liposarcoma does not behave as aggressively as most pleomorphic sarcomas of adulthood; however, it has the capacity to metastasize, in contrast to its well-differentiated counterpart. We present a case of dedifferentiated liposarcoma arising in the pyriform sinus, an event only twice reported previously in the literature.     

Dedifferentiated liposarcoma with a paraganglioma-like histologic pattern: a case report and review of the literature

A 53-year-old man presented with a 4-month history of increasing abdominal discomfort and distension. A large retroperitoneal mass was found on imaging. Image-guided needle core biopsy demonstrated a poorly differentiated malignant neoplasm. A 30 x 32 x 33-cm soft tissue mass was removed. Microscopically, the tumor consisted of predominantly epithelioid malignant cells arranged in a paraganglioma-like growth pattern. Immunohistochemically, these cells were strongly positive for neuron-specific enolase. Stains for synaptophysin and chromogranin, however, were negative. There was no ultrastructural evidence of neuroendocrine differentiation. Adjacent sarcomatous areas were composed of spindled cells arranged in storiform and fibrosarcoma-like growth patterns. A small area of well-differentiated liposarcoma was identified, and a diagnosis of dedifferentiated liposarcoma was established. To the best of our knowledge, this represents the first reported case of dedifferentiated liposarcoma with a paraganglioma-like histologic pattern. A brief review focusing on the morphologic variations of dedifferentiated liposarcoma is also presented.     

Dedifferentiated liposarcoma of retroperitoneum and mesentery: varied growth patterns and histological grades--a clinicopathologic study of 32 cases

The purpose of this study was to obtain further information regarding cellular differentiation and proliferative characteristics of dedifferentiated liposarcoma (DDL) arising in the retroperitoneum and mesentery for accurate diagnosis and prognostic criteria. The patients included 20 men and 12 women, mean age, 60 years (range, 33 to 80 years). Twenty-seven tumors were located in the retroperitoneum and 5 in the mesentery. Tumor size ranged from 9 to 51 cm (mean, 24 cm). Follow-up was available on all patients and ranged from 4 to 243 months (mean, 64 months). Twenty-four (75%) patients developed local recurrences, 3 (9%) had distant metastasis, and 16 (50%) died of the disease. The predominant histology of dedifferentiation (DD) included fibrosarcoma or malignant fibrous histiocytoma (MFH) in 15 (47%), myxofibrosarcoma (myxoid MFH) in 5 (16%), mixed type in 10 (31%), and a whorling pattern in 2 (6%). Divergent differentiation, such as osseous, osteosarcomatous, chondrosarcomatous, and leiomyosarcomatous, was observed in 9 (28%). Immunoreactivity for vimentin, desmin, CD34, neurofilament, alpha-smooth muscle actin, p53, and MDM2 was observed in 32 (100%), 14 (44%), 8 (25%), 13 (41%), 14 (44%), 19 (59%), and 18 (56%) of DD areas, respectively. On the basis of a histological grading using MIB-1 (MIB-1 index range, 3% to 80%; mean, 27%) to replace mitosis counts (1 to 35/10 high-power fields [HPF]; mean, 13/10 HPF), 16 tumors each were classified as low-grade (grade 2) and high-grade (grade 3). The mixed type with poorly differentiated areas including scattered lipoblasts could be mistaken for myxoid liposarcoma but lacked the C/EBP-homologous protein-translocated in liposarcomat (CHOP-TLS) fusion genes specific for myxoid liposarcoma. Period to the first recurrence and histological grade using the MIB-1 index were associated with overall survival. Identification of DD areas, especially a poorly recognized variant of the mixed type, careful follow-up to detect early recurrence, and histological malignancy grading combined with proliferation indices are important in providing an accurate prognosis for all patients with retroperitoneal and mesenteric liposarcoma.     

Pleomorphic liposarcoma.

Pleomorphic liposarcoma (PLS) is defined as a high-grade pleomorphic sarcoma containing multivacuolated lipoblasts. PLS arises most frequently in the extremities of older individuals and often metastasizes to the lungs. The prognosis of PLS parallels that of many other high-grade sarcomas. In a small analysis combining clinicopathologic data available from 16 previously reported and 8 additional cases of PLS arising in the extremities, the 5-year overall survival rate for the 24 patients was 40% (median survival, 48 months). By univariate analysis, patients with tumors located in the upper extremities (P = .021) and greater than 10 cm (P = .047) had decreased overall survival. Older age, female sex, epithelioid phenotype, and radiotherapy or chemotherapy administration were not significantly associated with an adverse outcome.