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A 12-year-old girl developed a myxoid liposarcoma on the inner side of her right thigh. Liposarcomas are extremely rare at this age compared to benign lipoblastomas, which are the most frequent tumors of fatty tissue in childhood. The prognosis of myxoid liposarcoma is good, especially when, as in this patient, the tumor is located in the subcutis where a large and deep excision is possible and often curative.
Liposarcomas very rarely affect the oral cavity; in such cases the cheek is typically involved. Differential diagnosis between lipoma and other sarcomas is sometimes challenging because the macroscopic and histological features may be difficult to distinguish. Neoplasms with the morphology of lipoma should always receive a careful postoperative histopathologic evaluation. Complete surgical excision is the most effective treatment. We present a case of myxoid liposarcoma of the cheek, together with a literature review of intraoral liposarcomas reported during the last 60 years.
A 74-year-old woman presented with an acute left hemiplegia. CT demonstrated an irregular mass in the right parietal region of the brain. Two years previously, she had undergone wide local excision of a liposarcoma from her thigh. Craniotomy was performed and the lesion removed. Subsequent histology confirmed a liposarcoma. The brain is an exceptionally rare site of first recurrence of a liposarcoma. This case report presents a pathological rarity and briefly reviews the literature relevant to clinicians.
Well-differentiated lipomatous tumors constitute a histopathologic category whose nomenclature has been controversial, particularly with respect to the distinction between atypical lipomas of the extremities and well-differentiated liposarcomas of the retroperitoneum. To determine whether there were differences in image analytic parameters between these neoplasms, 72 lesions including 21 typical lipomas, 7 atypical lipomas, 16 retroperitoneal and 5 nonretroperitoneal well-differentiated, 9 dedifferentiated, and 14 pleomorphic liposarcomas were submitted to the computer-assisted microscopic analysis of Feulgen-stained nuclei. This methodology enabled four groups of variables to be calculated. These included: (1) quantitative chromatin pattern description (14 variables); (2) the measurement of proliferative activity (1 variable); (3) nuclear DNA content (DNA ploidy level, 5 variables); and (4) the measurement of cell density and topographical cell nuclei organization (2 variables). The results strongly suggest that atypical lipomas, whether superficial or deep, and well-differentiated liposarcomas, whether retroperitoneal or not, belong to the same category in terms of the variables analyzed.
Fifteen liposarcomas from 13 patients were examined by electron microscopy. These included nine primary tumors, four recurrent tumors after primary surgery or irradiation, and two metastatic lesions. Twelve of the liposarcomas were located in the thigh, and 11 were of the myxoid variety. All neoplasms were composed of cells having the ultrastructural characteristics of some stage of lipoblastic differentiation, i.e., lipid droplets, micropinocytotic vesicles, glycogen, external lamina, intermediate filaments, Golgi apparatuses, rough and smooth endoplasmic reticulum, and mitochondria. The nuclear-cytoplasmic ratio and nuclear pleomorphism were related inversely to the size and number of lipid droplets. Lipoblasts were frequently in close association with capillaries and pericytes, and in four cases lipid droplets were found in pericytes. Multivacuolated, mitochondria-rich lipoblasts, resembling brown fat cells, also were seen. Most tumors contained lipid-free, poorly differentiated mesenchymal cells that showed a continuum of morphologic differentiation to cells that closely resembled early lipoblasts that contained nonmembrane-bound lipid vacuoles. Fibrolipoblasts, cells containing lipid droplets and abundant rough endoplasmic reticulum, were observed only in well-differentiated liposarcomas. Some soft tissue sarcomas contain vacuolated cells that simulate lipoblasts by light microscopy but prove to be reactive or malignant fibroblasts, histiocytes, or smooth muscle cells ultrastructurally. Therefore, use of electron microscopy may be necessary to establish the line of differentiation in these neoplasms.
Primary liposarcoma of the stomach is rare and only seven cases have been described in the English literature. Here we report the eighth case, which occurred in a 68-year-old woman who presented with repeated tarry stools and hematemesis. Endoscopic examination revealed a large ulcerated submucosal mass at the gastric angle. The patient was treated by total gastrectomy. On microscopic examination, the tumor showed the features of a well differentiated sclerosing liposarcoma. Immunohistochemically, many spindle to stellate tumor cells were diffusely positive for vimentin and CD34. Positivity for S-100 protein was found in the adipocytic component, including lipoblasts, in addition to some spindle-shaped tumor cells. On ultrastructural examination, the spindle to stellate cells had features characteristic of fibroblasts. No recurrence or metastasis was seen during 13 months. Liposarcoma of the stomach has to be considered in the differential diagnosis with other submucosal lesions, such as gastric lipoma and gastrointestinal stromal tumor.
Myxoid liposarcoma can frequently metastasize to extrapulmonary sites. We present two cases of myxoid liposarcoma metastatic to the epidural space. Both patients complained of back pain, but plain radiography revealed no abnormality. MR imaging clearly demonstrated metastatic tumors in the epidural space, but no involvement of vertebra. When patients with myxoid liposarcoma complain of back pain, metastasis in the epidural space should be considered even in patients without bone involvement.
Primary mesenteric liposarcoma is a rare entity that has been reported only 14 times in English literature. The treatment strategy for mesenteric liposarcoma is, if no distant metastases are detected, surgical resection with a wide surgical margin, often followed by radiation and/or adjuvant chemotherapy for high-risk patients. However, the efficacy of pre-operative chemotherapy is unknown. If the tumor is shrunk by pre-operative chemotherapy, we could achieve complete surgical resection, which is difficult when the tumor is too large or is invading neighboring organs. We herein describe a case of huge mesenteric liposarcoma that showed significant tumor shrinkage by pre-operative chemotherapy using doxorubicin, cisplatin and ifosfamide, allowing a margin-negative operation.
The disease state of cancer appears late in tumor development. Before being diagnosed, a tumor can remain for prolonged periods of time in a dormant state. Dormant human cancer is commonly defined as a microscopic tumor that does not expand in size and remains asymptomatic. Dormant tumors represent an early stage in tumor development and may therefore be a potential target for nontoxic, antiangiogenic therapy that could prevent tumor recurrence. Here, we characterize an experimental model that recapitulates the clinical dormancy of human tumors in mice. We demonstrate that these microscopic dormant cancers switch to the angiogenic phenotype at a predictable time. We further show that while angiogenic liposarcomas expand rapidly after inoculation of tumor cells in mice, nonangiogenic dormant liposarcomas remain microscopic up to one-third of the normal severe combined immune deficiency (SCID) mouse life span, although they contain proliferating tumor cells. Nonangiogenic dormant tumors follow a similar growth pattern in subcutaneous (s.c.) and orthotopic environments. Throughout the dormancy period, development of intratumoral vessels is impaired. In nonangogenic dormant tumors, small clusters of endothelial cells without lumens are observed early after tumor cell inoculation, but the nonangiogenic tumor cannot sustain these vessels, and they disappear within weeks. There is a concomitant decrease in microvessel density, and the nonangiogenic dormant tumor remains harmless to the host. In contrast, microvessel density in tumors increases rapidly after the angiogenic switch and correlates with rapid expansion of tumor mass. Both tumor types cultured in vitro contain fully transformed cells, but only cells from the nonangiogenic human liposarcoma secrete relatively high levels of the angiogenesis inhibitors thrombospondin-1 and TIMP-1. This model suggests that as improved blood or urine molecular biomarkers are developed, the microscopic, nonangiogenic, dormant phase of human cancer may be vulnerable to antiangiogenic therapy years before symptoms, or before anatomical location of a tumor can be detected, by conventional methods.
We describe four patients with retroperitoneal liposarcomas undergoing myosarcomatous differentiation. The patients (two men and two women) were 47, 48, 68, and 72 years of age when first seen. The primary tumors were large retroperitoneal, well-differentiated liposarcomas, one featuring areas of dedifferentiation (without muscle elements). A myosarcomatous component became evident at the first recurrence in three cases and at the second recurrence in one. This component was always within dedifferentiated areas and in three of the cases coincided with the emergence of the latter. The muscle component had exclusively leiomyosarcomatous phenotype (alpha-smooth-muscle actin reactivity) in one case, exclusively rhabdomyosarcomatous phenotype (myoglobin reactivity) in two cases, and combined leiomyosarcomatous and rhabdomyosarcomatous phenotype (alpha-smooth-muscle actin and myoglobin) in one case. Ultrastructural studies of one of the tumors with a rhabdomyosarcomatous component revealed the presence of sarcomeres. Two patients died of extensive retroperitoneal disease, one patient died following the attempted removal of a recurrence, and one patient is alive and free of disease. These cases demonstrate that the dedifferentiated component of liposarcoma may exhibit a myosarcomatous component, a feature analogous to that previously described in dedifferentiated chondrosarcoma.
Two cases are described of a soft-tissue sarcoma characterized histologically by the intimate admixture of areas displaying the features of liposarcoma and leiomyosarcoma. Both cases occurred in men, 70 and 77 years of age. The lesions were located in the left scrotum and abdominal cavity, respectively. Histologically, the lipomatous component in both cases consisted predominantly of well-differentiated liposarcoma with myxoid areas. The smooth-muscle component was characterized by intersecting fascicles of spindle cells displaying nuclear atypicality and scattered mitotic figures; the spindle cells in these areas were strongly immunoreactive with actin and desmin antibodies. The above tumors must be distinguished from angiomyolipoma, spindle-cell lipoma, myolipoma of soft tissue, and more importantly, from "dedifferentiated" liposarcoma. The development of dual lineage differentiation within adipose tissue tumors as exemplified by these two cases may be more prevalent than has been generally recognized, and may require the application of immunohistochemical markers for specific identification of the spindle-cell component.
Nine well-differentiated liposarcomas with foci simulating the appearance of malignant lymphoma and other lymphoid disorders are reported. Their clinical presentation and evolution were not significantly different from those of their conventional counterparts lacking a lymphoid infiltrate. Microscopically, these tumors were characterized by areas of ordinary well-differentiated liposarcoma, admixed with discrete nodules comprised of small germinal centers, and separated by an admixture of lymphocytes, spindled stromal cells, collagen, and blood vessels, in which highly atypical tumor cells were embedded. The differential diagnosis included Hodgkin's disease, Castleman's disease, and inflammatory pseudotumor. Immunohistochemical evaluation revealed a pre-dominance of T cells in the lymphocytic population. Molecular genetic studies revealed no evidence of clonal rearrangement of the T cell receptor gene, supporting the interpretation of these lymphocytes as reactive. Awareness of the existence of this variant of inflammatory liposarcoma should prevent its misinterpretation as a primary lymphoproliferative process.
Nine cases of dedifferentiated liposarcoma with both a peculiar neurallike or meningeallike whorling pattern and metaplastic bone formation are reported. The tumors predominated in the retroperitoneum of elderly adults. All nine tumors were resected, and five of seven that were followed-up recurred locally, but none metastasized after a follow-up of 2 to 7 years. Grossly, most of the tumors were huge masses, ranging from 2.5 cm to 60 cm. Histologically, the tumors revealed, in addition to areas of well-differentiated liposarcoma, discrete nodules consisting of hypercellular, spindled to ovoid cellular proliferation arranged in tight, concentric whorls resembling neural tumors or meningiomas. Metaplastic, heterotopic ossification was present in seven of nine tumors and consisted of variable amounts of osteoblast-rimmed bone trabeculae situated at the periphery of the whorled areas or intimately mixed with the whorled cellular component. Immunohistochemical studies were inconclusive in determining the nature of the dedifferentiated, whorled element. Ultrastructural evaluation of one tumor disclosed neoplastic cells featuring thin, interdigitating cytoplasmic processes connected by desmosomes, similar to those described in follicular dendritic cell neoplasms. Although suggested by the light and electron microscopic features, the follicular dendritic cell differentiation of the dedifferentiated component could not be confirmed on immunohistochemical grounds, and the histogenesis of the intriguing neurallike or meningiomalike component in these dedifferentiated liposarcomas is unknown.
We describe the clinicopathologic features and biologic behavior of 16 cases of histologically benign hemangiopericytoma containing a variable amount of mature fat as an intrinsic part of the neoplasm. These so-called lipomatous hemangiopericytomas occurred primarily in men (12 men and 4 women) with a mean age of 54 years (range, 33-74 years). All occurred in deep soft tissue and had an average size of 10 cm when first detected. All were characterized by a relatively sharp border and typical histologic features of hemangiopericytomas, including oval to round cells surrounding a sinusoidal and staghorn vasculature often with perivascular hyalinization. Mature fat varied in amount but usually occupied approximately one quarter to three quarters of the area of tumor. Mitotic activity was low, with more than half the cases having no mitotic activity. Five cases showed moderate nuclear atypia. In four cases, the pericytic regions had sclerotic zones. In contrast to liposarcoma, neither lipoblasts nor isolated atypical hyperchromatic cells within mature fat, as are seen in well-differentiated liposarcoma, were present. Immunohistochemistry performed in four cases showed factor XIIIa in tumor cells and an intricate pattern of immunoreactivity around cells for type IV collagen. CD34 and smooth-muscle actins were identified in two of four cases. Follow-up in seven cases showed no recurrences or metastases within the follow-up period of 1 to 7 years. Because these lesions are located in deep soft tissue and contain large amounts of mature fat, they could be mistaken for well-differentiated liposarcomas in limited biopsy material, although the distinction is easily made in examining the entire specimen. The lipomatous hemangiopericytoma represents yet another example of a bimodal mesenchymal tumor containing mature fat and raises the question of whether a common cytogenetic abnormality can explain the emergence of two clonal populations in this hybrid tumor.
The clinicopathologic and immunohistochemical features of 63 pleomorphic liposarcomas are presented. There were 35 men and 28 women (median age 63 years; range 18-93 years). Tumor size ranged from 2 to 23 cm (median 10 cm). Tumor locations included lower extremity (36.5%), especially the thigh (28.5%), limb girdles (17.5%), upper extremity (16%), thoracoabdominal wall (9.5%), and internal trunk (20.5%). A total of 75% were deep seated and/or extracompartmental. Histologically, lesions show a varying combination of lipogenic and nonlipogenic areas characterized by malignant fibrous histiocytoma-like, round cell liposarcoma-like, and/or epithelioid/carcinoma-like features. A pericytic pattern was focally present in 15 (24%) tumors. Eighteen (29%) lesions were grade 2, and 45 (71%) were grade 3 sarcomas. Tumor necrosis was observed in 51 (81%) cases, vascular invasion in three, and mitotic counts ranged from 3 to 124 per 10 high power fields (median 25). Lipogenic areas were S-100 protein immunoreactive, at least focally, in 20 of 42 (48%) cases. Nonlipogenic areas showed focal reactivity for smooth muscle actin (24 of 49; 49%), desmin (9 of 48; 19%), CD34 (18 of 45; 40%), S-100 protein (5 of 49, 10%), CD68 (6 of 46, 13%), and epithelial membrane antigen (13 of 49, 26.5%). Epithelioid areas showed epithelial membrane antigen (4 of 11; 36%) but not cytokeratin (0 of 11) reactivity. Treatment procedures in 51 patients consisted of simple tumorectomy (16) and wide excision (33). Five and 31 patients received neoadjuvant and adjuvant chemotherapy and/or radiation therapy, respectively. Follow-up (48 patients, range 7-276 months; median 38 months) showed a 45% local recurrence rate and a 42.5% metastasis rate, metastases occurring mostly in lungs and pleura. Seventeen patients (35%) died of disease, of whom none was metastatic at diagnosis. Five-year overall, metastasis-free, and local recurrence-free survivals were 57%, 50%, and 48%, respectively. Patient age > or =60 years, truncal tumor location, deep situation, tumor size >5 cm, vascular invasion, and incomplete tumor excision were significant adverse prognostic factors. Tumor grade and histology did not affect patient outcome. In conclusion, pleomorphic liposarcoma is a rare, often deep-seated and limb-based aggressive and metastasizing neoplasm of late adulthood. It shows a wide range of morphologic appearances, but tumor grade and histology have no effect on patient outcome.
Leiomyosarcomatous (LMS) differentiation is a rare event in liposarcoma (LPS) and may consist of either well-differentiated liposarcoma (WDL) with an intrinsic smooth muscle component, so-called "lipoleiomyosarcoma," (L-LMS) or dedifferentiated liposarcoma having smooth muscle differentiation in the dedifferentiated zones. The latter are high-grade sarcomas, whereas the behavior of the former group is uncertain. Specifically, it is not clear whether the presence of LMS negatively affects the prognosis. We present our experience with nine cases, the largest to date. The patients (seven male, two female) ranged in age from 42 to 65 years (mean 54 years). The tumors were usually large (2 to >40 cm [mean 17 cm]) tumors in the retroperitoneum (two cases), paratesticular-inguinal region (three cases), mediastinum (one case), lung (one case), abdomen (one case), and popliteal fossa (one case). The nine cases qualified as L-LMS and showed typical WDL with a multifocal, gradual transition into smooth muscle areas. The latter areas accounted for a variable portion of the lesions (range 5-90%) and were of low cellularity, mild to moderate nuclear atypia, and low mitotic activity. These areas seemed to arise from or blend with the smooth muscle in the walls of large vessels within the tumor. One case showed areas of dedifferentiation consisting of actin and desmin-negative, high-grade sarcoma. Follow-up in seven cases (range 26-312 months; mean 119 months) showed multiple local recurrences in seven patients and no metastases. Three patients are currently without evidence of disease (follow-up duration 26-312 months; mean 144 months) and four patients are alive with progressive disease (follow-up duration 60-132 months; mean 99 months). Our study suggests that L-LMS is a dual lineage sarcoma as evidenced by the fact that the smooth muscle component is often multifocal, not necessarily found in close association with the atypical changes in fat, and seemingly originates from atypical ("in situ") changes in the vessel wall. The LMS component, which is typically low grade, does not adversely affect the overall behavior of the tumor, which is similar to that of conventional WDL. LMS in L-LMS should not be misconstrued as evidence of low-grade dedifferentiation, a phenomenon that identifies a more unstable and potentially metastasizing lesion.
Isolated acquired factor VII (FVII) deficiency (0.15 U/ml) was identified in a 30-year-old man with pleural liposarcoma. The patient underwent surgery with continuous FVII concentrate infusion. No anti-FVII antibody or FVII/anti-FVII complex was detected. However, the short half-life and low recovery of FVII after concentrate infusion suggested the presence of an antibody. Whatever the mechanism, this FVII deficiency was related to the presence of the liposarcoma. FVII level normalized during tumour regression and fell again when the liposarcoma relapsed.
Although carcinoma is rarely metastatic to the thyroid gland, it has an established place in the differential diagnosis of cold nodules on radionuclide thyroid scans in patients with known cancers. A case of metastatic pleomorphic liposarcoma with involvement of the thyroid gland adds to the list of cases of metastases to the thyroid gland. A patient with known metastatic pleomorphic liposarcoma with a palpable thyroid nodule of 2 months' duration had a thyroid scan with 130 MBq (3.5 mCi) Tc-99m pertechnetate. The scan showed a cold nodule occupying most of the right lobe of the thyroid. Cytologic analysis of a fine-needle aspirate from this cold nodule confirmed metastasis from the known primary cancer, pleomorphic liposarcoma. In a patient with a known primary tumor, a nodule in the thyroid gland should be considered a metastatic lesion, regardless of the time since the primary tumor was diagnosed and treated, until proved otherwise.