Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma with Myxoid Stroma in a Hereditary Retinoblastoma Survivor

Atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDL) is an indolent, locally aggressive mesenchymal neoplasm, most often confined to the lower extremities and retroperitoneum and rarely identified in the orbit. Diagnosis of ALT/WDL can be challenging due to its frequent morphologic overlap with benign adipose lesions and other more aggressive liposarcoma subtypes, including myxoid liposarcoma. We describe a 26-year-old female with a history of hereditary retinoblastoma and external-beam radiotherapy to the orbit, who developed orbital liposarcoma. Although initial morphologic assessment raised the consideration of myxoid liposarcoma, subsequent fluorescein in situ hybridization studies demonstrated MDM2 and DDIT3 coamplification without DDIT3 rearrangement, supporting the diagnosis of ALT/WDL with myxoid stroma. The literature review of previously reported orbital myxoid liposarcomas revealed a morphologic overlap of documented tumors with ALT/WDL, dedifferentiated liposarcoma, and pleomorphic liposarcoma with myxoid stroma as well as an absence of immunohistochemical and molecular genetic data supportive of the diagnosis of myxoid liposarcoma. This case emphasizes the potential overlap of ALT/WDL with myxoid liposarcoma and the increasing importance of molecular genetic studies in the diagnosis, prognosis, and management of orbital liposarcoma.

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Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma with Intramuscular Lipoma-Like Component of the Thigh

Case Reports in Surgery ◽

10.1155/2020/8846932 ◽

2020 ◽

Vol 2020 ◽

pp. 1-6

Author(s):

Chairat Burusapat ◽

Nuttadon Wongprakob ◽

Nutthapong Wanichjaroen ◽

Chatchai Pruksapong ◽

Kantang Satayasoontorn

Keyword(s):

Growth Pattern ◽

English Literature ◽

Atypical Lipomatous Tumor ◽

Lipomatous Tumor ◽

Large Size ◽

Intramuscular Lipoma ◽

Mesenchymal Neoplasm ◽

Infiltrative Growth Pattern ◽

Well Differentiated ◽

Painless Mass

Atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDLPS) is a locally aggressive mesenchymal neoplasm composed either entirely or partly of an adipocytic proliferation showing at least focal nuclear atypia in both adipocytes and stromal cells. ALT most frequently occurs in deep soft tissue of proximal extremities (thigh and buttock) and usually presents as a deep-seated, painless mass that can slowly attain a very large size, which is one of the most common sarcomas of extremity. In the patients who presented with deep-seated tumor, distinction between intramuscular lipoma and well-differentiated liposarcoma is important due to the differences in treatment and prognosis. However, atypical well-differentiated liposarcoma with intramuscular lipoma-like component of the thigh is extremely rare. Moreover, the infiltrative growth pattern or intramuscular component may lead to a misinterpretation as intramuscular lipoma on a small biopsy. We present an unusual case of a female who presented with symptomatic mass at the thigh which has rarely been reported in English literature as an infiltrative intramuscular lipoma-like growth pattern of well-differentiated liposarcoma. Therefore, preoperative diagnosis is necessary, and correlation with imaging studies is required when one encounters with a large deep-seated mass. Atypical lipomatous tumor or well-differentiated liposarcoma should be kept in mind in the patient who presents with abnormal thigh mass.

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P16 as a marker to differentiate atypical lipomatous tumor/well-differentiated liposarcoma from deep seated lipoma: An immunohistochemical analysis of 51 cases

Journal of Clinical Oncology ◽

10.1200/jco.2007.25.18_suppl.10070 ◽

2007 ◽

Vol 25 (18_suppl) ◽

pp. 10070-10070

Author(s):

M. He ◽

S. Aisner ◽

J. Benevenia ◽

F. Patterson ◽

H. Aviv ◽

...

Keyword(s):

Signal Transduction Pathway ◽

Specific Inhibitor ◽

Immunohistochemical Analysis ◽

Early Event ◽

Mdm2 Gene ◽

Atypical Lipomatous Tumor ◽

Lipomatous Tumor ◽

Mesenchymal Neoplasm ◽

Well Differentiated ◽

P16 Expression

10070 Background: Atypical lipomatous tumor (ALT)/well-differentiated (WD) liposarcoma is a locally aggressive malignant mesenchymal neoplasm characterized by supernumerary ring and giant marker chromosomes with amplification of MDM2 gene. These cytogenetic characteristics can be very helpful to distinguish ALT from deep-seated lipomas. As ALTs have only rare presence of lipoblasts, they can resemble benign lipomas rendering difficulty in morphological diagnosis. P16INK4 is a specific inhibitor of CDK4/CDK6. CDK6 gene is often found co-amplified with MDM2 gene in ALTs. P16 overexpression is a hallmark of cervical dysplasia. Our study investigates the value of p16 expression in cytogenetically confirmed ALTs and deep-seated lipomas. Design: Fifty-one (51) cases of lipomatous neoplasms, with cytogenetic results, from forty-three (43) patients were collected for the study from the archives in department of pathology, UMDNJ/NJMS during 1998 - 2005. These include 18 cases of deep-seated lipoma, one hibernoma, and 32 cases of ALT / well-differentiated liposarcoma (24 patients, five patients with recurrence, and four cases with de-differentiation). Immunohistochemical staining for p16 was performed on representative paraffin blocks. Staining results were scored according to intensity (negative 0, weak 1+, intermediate 2+, and strong 3+) and percentage of positive cells. Results: Twenty-eight cases (28/32, 87.5%) of ALT/WD liposarcoma, including all four cases of dedifferentiated liposarcoma, showed strong nuclear p16 expression. In cases of recurrence, the primary and recurrent tumor showed the same pattern of p16 staining. Four cases (4/32, 12.5%) of ALT/WD liposarcoma showed negative p16 expression. All cases of deep-seated lipoma (18/18, 100%) and single hibernoma showed negative p16 staining except focal positivity in areas of fat necrosis in two cases (p16 positivity, 87.5 vs. 0%, P <0.00001, Fisher's exact test). Conclusion: 1). P16 appears to be a valuable marker to differentiate ALT and deep-seated lipomas. 2). P16 expression remains unchanged in progression and transformation of ALT. 3). P16 related signal transduction pathway most likely is an early event in tumorogenesis of ALT. No significant financial relationships to disclose.

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“Fat-Rich” (Spindle Cell-Poor) Variant of Atypical Spindle Cell/Pleomorphic Lipomatous Tumor: Striking Mimic of “Classical” Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma

International Journal of Surgical Pathology ◽

10.1177/1066896919846561 ◽

2019 ◽

Vol 27 (8) ◽

pp. 868-871 ◽

Cited By ~ 4

Author(s):

David Creytens ◽

Thomas Mentzel ◽

Liesbeth Ferdinande ◽

Joost van Gorp ◽

Jo Van Dorpe ◽

...

Keyword(s):

Spindle Cell ◽

Molecular Genetic ◽

Low Grade ◽

Tissue Mass ◽

Atypical Lipomatous Tumor ◽

Lipomatous Tumor ◽

Multinucleated Cells ◽

Pericytic Mimicry ◽

Well Differentiated ◽

The Right

We report the case of a “fat-rich” (spindle cell-poor) variant of an atypical spindle cell/pleomorphic lipomatous tumor in a 63-year-old female patient presenting with a firm, painless soft tissue mass on the right hip. Atypical spindle cell/pleomorphic lipomatous tumor is a very recently described low-grade adipocytic neoplasm, which occurs predominantly in adults with a predilection for the limbs and limb girdles. In the present case, the diagnosis of an atypical spindle cell/pleomorphic lipomatous tumor was challenging because the tumor was almost exclusively composed of an atypical adipocytic component (resembling “classical” atypical lipomatous tumor/well-differentiated tumor) with only very focal presence of the diagnostic atypical morphologic features (atypical spindle-shaped cells, floret-like multinucleated cells, and “bizarre” pleomorphic [multinucleated] cells). The possibility of a “classical” atypical lipomatous tumor/well-differentiated liposarcoma was ruled out by immunohistochemistry (lack of MDM2 expression and loss of Rb expression) and molecular genetic testing (no amplification of MDM2 and presence of monoallelic deletion of RB1). Another interesting morphologic observation in this case was the striking perivascular location of the atypical spindle/pleomorphic cells in some areas (so-called “pericytic mimicry”). To our knowledge, pericytic mimicry has not been reported in the setting of an atypical spindle cell/pleomorphic lipomatous tumor.

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Translocations and Amplifications of Chromosome 12 in Liposarcoma Demonstrated by the LSI CHOP Breakapart Rearrangement Probe

Archives of Pathology & Laboratory Medicine ◽

10.5858/2008-132-952-taaoci ◽

2008 ◽

Vol 132 (6) ◽

pp. 952-957

Author(s):

Carlynn Willmore-Payne ◽

Joseph Holden ◽

Kristi C. Turner ◽

Alan Proia ◽

Lester J. Layfield

Keyword(s):

Signal Amplification ◽

Myxoid Liposarcoma ◽

Chromosome 12 ◽

Round Cell ◽

High Background ◽

Molecular Abnormalities ◽

Not Otherwise Specified ◽

Myxoid Liposarcomas ◽

Well Differentiated ◽

Atypical Lipomatous Tumors

Abstract Context.—Liposarcomas display a number of molecular abnormalities involving chromosome 12. Myxoid and round cell liposarcomas are characterized by t(12;16)(q13; p11) or t(12;22)(q13;q12) translocations. Amplifications occur within the 12q13-15 region of atypical lipomatous tumors and well-differentiated liposarcomas but not lipomas. Objective.—To investigate the performance characteristics of the LSI CHOP Breakapart Rearrangement Probe for the diagnosis of myxoid/round cell liposarcomas and atypical lipomas/well-differentiated liposarcomas. Design.—We investigated a series of lipomatous neoplasms (5 lipomas, 5 well-differentiated liposarcomas, 22 myxoid/round cell liposarcomas, 2 liposarcomas not otherwise specified, and 2 dedifferentiated liposarcomas) and normal myometrium for abnormalities in the q13-15 region of chromosome 12. Cases were studied for the presence or absence of t(12;16)(q13;p11) or t(12;22)(q13;q12) translocations by the LSI CHOP Breakapart Rearrangement Probe. These probes contain a sequence encompassing the SAS and CDK4 genes. Four or more copies of this sequence were considered to represent amplification of these genes. Results.—Rearrangement of the CHOP gene was seen in all evaluable myxoid liposarcomas. Rearrangements were seen in 1 dedifferentiated liposarcoma but not in normal myometrium or lipomas. Probe signal amplification was seen in all 5 well-differentiated liposarcomas and 1 myxoid liposarcoma. No signal amplification was seen in lipomas or myometrium. Conclusions.—Demonstration of translocations t(12; 16)(q13;p11) and t(12;22)(q13;q12) by the LSI CHOP Breakapart Rearrangement Probe appears to correlate with round cell/myxoid liposarcoma. The probe also demonstrated amplification of the 12q13-15 region in well-differentiated liposarcomas, making it useful for the diagnosis of these neoplasms. In a significant percentage of cases, high background fluorescence or poor probe staining made interpretation difficult.

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Orbital Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma Masquerading as Pleomorphic Lipoma

Ophthalmic Plastic and Reconstructive Surgery ◽

10.1097/iop.0000000000001378 ◽

2019 ◽

Vol 35 (3) ◽

pp. e76-e80 ◽

Cited By ~ 1

Author(s):

Kyle McKey ◽

Paul J. L. Zhang ◽

Carol L. Shields ◽

Sara E. Lally ◽

Ralph C. Eagle ◽

...

Keyword(s):

Atypical Lipomatous Tumor ◽

Lipomatous Tumor ◽

Pleomorphic Lipoma ◽

Well Differentiated

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Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma of the Gingiva: A Case Report and Review of Literature

Journal of Oral and Maxillofacial Surgery ◽

10.1016/j.joms.2013.06.222 ◽

2014 ◽

Vol 72 (2) ◽

pp. 431-439 ◽

Cited By ~ 12

Author(s):

Young Bin Kim ◽

Dae Ho Leem ◽

Jin A. Baek ◽

Seung O. Ko

Keyword(s):

Case Report ◽

Review Of Literature ◽

Atypical Lipomatous Tumor ◽

Lipomatous Tumor ◽

Well Differentiated

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A Retrospective Study of Superficial Type Atypical Lipomatous Tumor

Frontiers in Medicine ◽

10.3389/fmed.2020.609515 ◽

2020 ◽

Vol 7 ◽

Author(s):

Emi Mashima ◽

Yu Sawada ◽

Natsuko Saito-Sasaki ◽

Kayo Yamamoto ◽

Shun Ohmori ◽

...

Keyword(s):

Surgical Resection ◽

Tumor Size ◽

Clinical Characteristics ◽

Clinical Manifestations ◽

Tumor Location ◽

Atypical Lipomatous Tumor ◽

Lipomatous Tumor ◽

Physical Examinations ◽

Superficial Type ◽

Well Differentiated

Atypical lipomatous tumor (ALT) has been defined as a well-differentiated liposarcoma exhibiting a higher frequency of a local recurrence after surgical resection. ALT is mainly classified into deep type and superficial type. Compared with deep type ALT, superficial type ALT is rarely observed. One of the most important issues is that little has been known about superficial type ALT and it is not easy to predict the presence of superficial type ALT before surgical resection. To clarify the clinical manifestations of superficial type ALT, we examined 15 cases with superficial type ALT and 118 cases with benign lipoma, and analyzed their differences in clinical characteristics and the findings of MRI test. In clinical characteristics, the tumor size of superficial type ALT was significantly greater than that of benign lipoma, and superficial type ALT showed a significantly higher frequency of the tumor size of more than 4 cm. Superficial type ALT exhibited poor tumor mobility and hardness with elastic soft. In addition, a significantly higher frequency of tumor location of superficial type ALT was observed in extremities. Among tumor sites at the trunk, buttocks, and shoulder were high frequent location in superficial type ALT. In an MRI examination, superficial type ALT exhibited a significantly higher frequency of the septal structures compared with benign lipoma. The combinations of clinical characteristics, including physical examinations, MRI, and histological examinations, are helpful for the diagnosis of superficial type ALT.

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