Atypical spindle cell lipomatous tumor/atypical pleomorphic lipomatous tumor and atypical mammary-type myofibroblastoma

Spindle cell lipomas are usually located in the subcutaneous tissue of the back, shoulders, and neck. To our knowledge, the presence of such a tumor in the parapharyngeal space has not yet been described. We evaluated a 45-year-old man with a tender swelling of the right parotid area that had reached the submandibular area. Clinical examination and magnetic resonance imaging revealed the presence of a tumor that coated the parotid area laterally and extended into the center of the parapharyngeal space, thus causing a dislocation of the pharyngeal muscles and mucosa. We performed a total parotidectomy and submandibulectomy on the right side and extirpated the parapharyngeal tumor. We were able to spare the facial nerve, and no facial paralysis occurred. Histologic examination revealed an atypical lipomatous tumor with a remarkably large portion of spindles.

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FluorescenceIn SituHybridization forMDM2Amplification as a Routine Ancillary Diagnostic Tool for Suspected Well-Differentiated and Dedifferentiated Liposarcomas: Experience at a Tertiary Center

Sarcoma ◽

10.1155/2015/812089 ◽

2015 ◽

Vol 2015 ◽

pp. 1-10 ◽

Cited By ~ 38

Author(s):

Khin Thway ◽

Jayson Wang ◽

John Swansbury ◽

Toon Min ◽

Cyril Fisher

Keyword(s):

Gene Amplification ◽

Diagnostic Tool ◽

Spindle Cell ◽

Significant Group ◽

Lipomatous Tumor ◽

Tertiary Center ◽

Benign Histology ◽

Well Differentiated ◽

Correlation Rate

Background. The assessment ofMDM2gene amplification by fluorescencein situhybridization (FISH) has become a routine ancillary tool for diagnosing atypical lipomatous tumor (ALT)/well-differentiated liposarcoma and dedifferentiated liposarcoma (WDL/DDL) in specialist sarcoma units. We describe our experience of its utility at our tertiary institute.Methods. All routine histology samples in whichMDM2amplification was assessed with FISH over a 2-year period were included, and FISH results were correlated with clinical and histologic findings.Results. 365 samples from 347 patients had FISH forMDM2gene amplification. 170 were positive (i.e., showedMDM2gene amplification), 192 were negative, and 3 were technically unsatisfactory. There were 122 histologically benign cases showing a histology:FISH concordance rate of 92.6%, 142 WDL/DDL (concordance 96.5%), and 34 cases histologically equivocal for WDL (concordance 50%). Of 64 spindle cell/pleomorphic neoplasms (in which DDL was a differential diagnosis), 21.9% showedMDM2amplification. Of the cases with discrepant histology and FISH, all but 3 had diagnoses amended following FISH results. For discrepancies of benign histology but positive FISH, lesions were on average larger, more frequently in “classical” (intra-abdominal or inguinal) sites for WDL/DDL and more frequently core biopsies. Discrepancies of malignant histology but negative FISH were smaller, less frequently in “classical” sites but again more frequently core biopsies.Conclusions. FISH has a high correlation rate with histology for cases with firm histologic diagnoses of lipoma or WDL/DDL. It is a useful ancillary diagnostic tool in histologically equivocal cases, particularly in WDL lacking significant histologic atypia or DDL without corresponding WDL component, especially in larger tumors, those from intra-abdominal or inguinal sites or core biopsies. There is a significant group of well-differentiated adipocytic neoplasms which are difficult to diagnose on morphology alone, in which FISH forMDM2amplification is diagnostically contributory.

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Atypical Spindle Cell Lipomatous Lesion Resected From Patient With History of CLL

The American Surgeon ◽

10.1177/0003134820933601 ◽

2020 ◽

Vol 86 (9) ◽

pp. 1208-1211

Author(s):

Chase J. Wehrle ◽

J. Will Daigle ◽

Asad Ullah ◽

Suash Sharma ◽

Edmond F. Ritter ◽

...

Keyword(s):

Spindle Cell ◽

Lymphocytic Leukemia ◽

Left Shoulder ◽

Spindle Cell Lipoma ◽

Atypical Lipomatous Tumor ◽

Lipomatous Tumor ◽

Adipocytic Tumors ◽

History Of ◽

Pathologic Analysis ◽

Mdm2 Amplification

Atypical spindle cell lipomatous neoplasm, also known as well-differentiated spindle cell liposarcoma, represents a newly discovered entity of adipocytic tumors. Recent research has shown this tumor variant to be more related to spindle cell lipoma, rather than the originally hypothesized atypical lipomatous tumor spectrum. Here we present a case of a 58-year-old man with a history of chronic lymphocytic leukemia with an enlarging mass on the posterior left shoulder, initially hypothesized to be a benign lipoma. However, magnetic resonance imaging showed a large, multiseptated, heterogeneous mass concerning for soft tissue sarcoma. After resection, pathologic analysis showed cells closely resembling spindle cell lipoma, with additional cellular and fascicular zones containing lipoblasts and mitotic figures. Molecular analysis showed no MDM2 amplification. This lack of amplification indicates this tumor is distinctly different from an atypical lipomatous tumor, which characteristically displays MDM2 amplification. However, tumor expression of RB1 was normal. The majority of atypical spindle cell lipomatous neoplasms are associated with RB1 deletions. We conclude that we have a unique example of an atypical spindle cell lipomatous tumor.

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Response to ““Dysplastic Lipoma” Is Probably Not a Separate Entity but Rather Belongs to the Morphological Spectrum of Atypical Spindle Cell/Pleomorphic Lipomatous Tumor”

International Journal of Surgical Pathology ◽

10.1177/1066896920946174 ◽

2020 ◽

Vol 28 (8) ◽

pp. 931-931

Author(s):

Michael A. den Bakker

Keyword(s):

Spindle Cell ◽

Separate Entity ◽

Lipomatous Tumor

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“Dysplastic Lipoma” Is Probably Not a Separate Entity but Rather Belongs to the Morphological Spectrum of Atypical Spindle Cell/Pleomorphic Lipomatous Tumor

International Journal of Surgical Pathology ◽

10.1177/1066896920939657 ◽

2020 ◽

Vol 28 (8) ◽

pp. 929-930

Author(s):

David Creytens

Keyword(s):

Spindle Cell ◽

Separate Entity ◽

Lipomatous Tumor

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Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma With Features Mimicking Spindle Cell Lipoma

International Journal of Surgical Pathology ◽

10.1177/1066896919884648 ◽

2019 ◽

Vol 28 (3) ◽

pp. 336-340 ◽

Cited By ~ 1

Author(s):

Judith A. S. Jebastin ◽

Kyle D. Perry ◽

Dhananjay A. Chitale ◽

Michael P. Mott ◽

Jessica Sanchez ◽

...

Keyword(s):

Spindle Cell ◽

Spindle Cell Lipoma ◽

Rb1 Gene ◽

Prognostic Features ◽

Atypical Lipomatous Tumor ◽

Lipomatous Tumor ◽

Well Differentiated ◽

Mdm2 Amplification ◽

Lipomatous Tumors

Atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDL) and spindle cell lipoma are lipomatous tumors with distinct clinical, molecular, and prognostic features. Although histological and immunophenotypic features can overlap between ALT/WDL and spindle cell lipoma, the oncogenesis and clinical behavior are markedly different. In borderline cases, molecular analysis for MDM2 or CDK4 amplification can aid in distinguishing ALT/WDL from spindle cell lipoma. Although dedifferentiated liposarcoma has been reported to harbor both MDM2 amplification and loss of the RB1 region, we are not aware of a reported RB1 loss in well-differentiated ALT/WDL. In this article, we present a 69-year-old woman with a lipomatous tumor in the gluteal region that histologically, immunohistochemically, and molecularly mimicked spindle cell lipoma (with positive immunohistochemical staining for CD34 and loss of the RB1 gene region), yet harbored amplification of MDM2 and CDK4 confirmed by fluorescence in situ hybridization, supporting classification as ALT/WDL. This case strengthens the argument that in atypical clinical contexts, molecular studies for MDM2/CDK4 should be considered in tumors resembling spindle cell lipoma.

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Primary Cutaneous Atypical Spindle Cell Lipomatous Tumor

Case Reports in Pathology ◽

10.1155/2021/4082289 ◽

2021 ◽

Vol 2021 ◽

pp. 1-4

Author(s):

Madeline S. Tchack ◽

Michael Broscius ◽

Martin Reichel

Keyword(s):

Spindle Cell ◽

Histopathological Examination ◽

Reticular Dermis ◽

Documented Case ◽

Lipomatous Tumor

This report documents an exophytic, pedunculated nodule in a 74-year-old man that upon histopathological examination revealed an atypical spindle cell/pleomorphic lipomatous tumor (ASPLT) confined to the papillary and reticular dermis, representing the fourth documented case within the skin. Despite the overt pleomorphic changes present histologically, the patient is free of metastasis or recurrence five years after surgery.

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