| Abstract|| |
This is a description of a dedifferentiated liposarcoma seen in a 27-year-old female patient. The tumor originated from the vallecula and contains distinctive bodies. These bodies, which are formed by the aggregation of tumor cells, contain collagen in several regions and are oval or elongated in shape. Immunohistochemically, the tumor cells showed staining for MDM2, p16, Vimentin, beta catenin, smooth muscle actin, bcl-2 and p53. Ki-67 ratio was 17% in hypercellular areas of the tumor. Molecular genetic studies have found copy number increase for CDK4 and MDM2 genes. Final histopathological diagnosis was dedifferentiated liposarcoma with unique bodies. Although meningothelial-like whorls is defined in dedifferentiated liposarcoma, this body has not been defined until now. To our knowledge, this is the first case of a DDL containing a cellular spindle cell component seen as rare sheet-like areas and distinctive ball-like, or elongated, serpiginous formations in the middle of paucicellular, collagenous areas.
Keywords: Larynx, liposarcoma, soft tissue, spindle cell, tumor
|How to cite this article:|
Ugras S, Miettinen M. New defining body (Ugras body) in polypoid dedifferentiated liposarcoma of the vallecula. Histomorphological, immunohistochemical and molecular genetic findings. Indian J Pathol Microbiol 2020;63:449-52
|How to cite this URL:|
Ugras S, Miettinen M. New defining body (Ugras body) in polypoid dedifferentiated liposarcoma of the vallecula. Histomorphological, immunohistochemical and molecular genetic findings. Indian J Pathol Microbiol [serial online] 2020 [cited 2020 Sep 24];63:449-52. Available from: http://www.ijpmonline.org/text.asp?2020/63/3/449/291680
| Introduction|| |
We described a case of dedifferentiated liposarcoma (DDL) with Ugras bodies originating from the vallecula and containing distinctive and characteristic bodies with overexpression of MDM2 and CDK4, showing diffuse staining for MDM2 and p16, which to our knowledge is the first case in English literature.
| Case History|| |
A 27-year-old white woman was admitted to the Otorhinolaryngological Clinic on May 2018 due to long-term hoarseness and difficulty in swallowing and breathing. Physical, oropharyngeal, otoscopic, anterior rhinoscopic exams, and hemogram were normal. The endoscopic examination revealed a polypoid tumorous mass that was located in the vallecula and lateral wall. Endolaryngeal microsurgery was performed and after the larynx was suspended, a 3 × 2 cm mass originating from the vallecula and lateral wall was totally excised.
Macroscopically, this polypoid mass was grayish-white in color, with well-circumscribed margins, measuring 3 × 2.5 × 1.6 cm in diameter, and had a whitish-gray appearance on cut sections [Figure 1]a and [Figure 1]b. No foci of hemorrhage, necrosis, calcification, or areas of cystic change were observed.
|Figure 1: (a and b) Polypoid mass. (c) Stratified squamous epithelium (arrows) and numerous bodies in tumor tissue (Hematoxylin-eosin, original magnification X20). (d) Numerous bodies (Hematoxylin-eosin, original magnification X100). (e) Body (Hematoxylin-eosin, original magnification X400). (f) Body (Hematoxylin-eosin, original magnification X600)|
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Microscopically, stratified squamous epithelium was seen on the outer surface and beneath this layer, spindle cell neoplasm observed [Figure 1]c. There were hypercellular and hypocellular areas in low grade spindle cell neoplasm. The tumor had slender and slightly plump cells that were arranged in short, irregular bundles, a hemangiopericytoma-like vascular pattern. The tumor cells had abundant faintly eosinophilic cytoplasm, elongated vesicular nuclei and small nucleoli. There were an average of 17 mitoses per 10 high-power fields and mild atypia in hypercellular areas of the tumor. Although the entire tumor tissue was examined, the lipomatous and liposarcomatous component were not seen. Tumor cells were observed on the surgical margins of the mass.
Numerous distinctive ball-like or elongated, serpiginous formations were seen in tumor tissue. These bodies were prevalent and more prominent in the hypocellular regions of the tumor. These bodies, which are formed by the aggregation of tumor cells, contain collagen in several regions and are oval or elongated in shape [Figure 1]d, [Figure 1]e, [Figure 1]f.
Hyalinization and scattered lymphocytes were also identified in the tumor. No areas of necrosis, nuclear pleomorphism or hemorrhage were seen [Figure 2]a, [Figure 2]b, [Figure 2]c, [Figure 2]d, [Figure 2]e, [Figure 2]f. Abundance of collagen, especially more prominent in the hypocellular areas was observed.
|Figure 2: (a) Hypercellular area (Hematoxylin-eosin, original magnification X40). (b) Hypercellular area (Hematoxylin-eosin, original magnification X100). (c) Short and irregular bundles in the hypercellular area (Hematoxylin-eosin, original magnification X200). (d) Tumor cells and two mitoses (arrows) (Hematoxylin-eosin, original magnification X600). (e) A hemangiopericytoma-like vascular pattern (Hematoxylin-eosin, original magnification X40). (f) A hemangiopericytoma-like vascular pattern and body (Hematoxylin-eosin, original magnification X100)|
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Tumor tissue was accompanied by dense mature birefringent collagen staining with Masson Trichrome [Figure 3]a and [Figure 3]b. Immunohistochemically, the tumor cells showed diffuse staining for MDM2, p16, Vimentin, beta catenin (cytoplasmic), smooth muscle actin, bcl-2, p53 and, focal staining for LCA and CD68. Ki-67 ratio was 17% in hypercellular areas of the tumor [Figure 3]c, [Figure 3]d, [Figure 3]e, [Figure 3]f. Immunostains for CD31, CD34, FLI-1, Desmin, HMB-45, S-100, MPO, p63, EMA, Pancytokeratin, Smooth muscle myosin heavy chain, Myogenin, smooth muscle actin, SOX10, MUC4, ALK, Synaptophysin, CD1a, and CD23 were consistently negative. Trimethylation of histone 3 at codon lysine 27 is retained. Immunohistochemical studies do not give evidence for any specific lineage.
|Figure 3: (a) Strong and diffuse collagen expression in tumor tissue and body (Masson Trichrome, original magnification X100). (b) Collagen expression in body (Masson Trichrome, original magnification X400). (c) Strong and diffuse Vimentin expression in tumor tissue (Vimentin, original magnification X200). (d) Weak and focal SMA expression in tumor tissue and body (SMA, original magnification X400). (e) bcl-2 expression in tumor tissue (bcl-2, original magnification X200). (f) Ki-67 expression in the hypercellular area (Ki-67, original magnification X200)|
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Molecular genetic (Oncomine comprehensive Assay v3) studies to be done for a definitive diagnosis and ensured these tests were done at the National Institutes of Health/National Cancer Institute. Molecular genetic studies have found copy number increase for CDK4 and MDM2 genes. Final histopathological diagnosis was DDL with Ugras bodies. The patient showed no sign of recurrence or metastases in her latest follow-up exam on December 2018.
| Discussion|| |
DDL accounts for approximately 10% of all liposarcomas and that occurs most frequently in the retroperitoneum in adults, followed by the deep soft tissue of the limbs, trunk, mediastinum, head and neck region, and spermatic cord.
Only about 5.6% of liposarcomas are found in the head and neck, and most of the tumors arise from the soft tissues of the neck. Laryngeal/hypopharyngeal liposarcomas (LHLs) are very rare, fewer than 40 cases have been reported.,
LHLs are polypoid, with a male predisposition and usually cause hoarseness and difficulty breathing. Grossly are white/tan lobulated polypoid mass. Most of the tumors are less than 5 cm in the greatest dimension. Well-differentiated liposarcoma (WDL) is by far the predominant subtype in LHLs.
Histologically, DDL has a wide morphologic spectrum, and most frequently manifests histologically with features of undifferentiated pleomorphic or spindle cell sarcoma. More rarely, DDL are morphologically 'low-grade', and show relatively low to moderate cellularity, with bland, often non-pleomorphic histologic features. The diagnosis of DDL can be difficult in neoplasms that lack a component of WDL, and in patients who lack a previous history of WDL.
Occasionally, the non-lipogenic component of DDL may show a peculiar spindle cell proliferation organized in distinctive whorls, reminiscent of neural or meningothelial structures often associated with metaplastic bone formation, and more rarely, with a plasmacytic inflammatory infiltrate.,,,
The vast majority (92%) of DDL express MDM2 and CDK4 immunohistochemically, with strong correlation of marker expression with gene amplification status. p16 is the most sensitive and specific marker for DDL, while MDM2 is the least. 93% of DDL express at least 2 antigens of the group of CDK4, MDM2 and p16, and CDK4 and p16 together, is of better discriminatory value than either with MDM2.
MDM2 and CDK4 overexpression and diffuse staining for MDM2 and p16 were seen in our tumor. DDL should be distinguished from other spindle cell neoplasms.
Our tumor is different from other spindle cell neoplasms showing MDM2 and CDK4 overexpression or lacking MDM2 and CDK4 overexpression. The most important finding constituting this difference, is the dispersion of distinctive bodies within this background. We have not come across this finding in any other soft tissue tumor.
Their clinical course of LHLs is characterized by multiple local recurrences. No distant metastasis has been reported and dedifferentiation is extremely rare. The prognosis of these tumors is excellent; the 5-year survival rate is essentially 100%.
In the light of the histomorphological, histochemical, immunohistochemical and molecular genetic findings, we diagnosed as DDL with Ugras bodies. However, further clinical, ultrastructural, histochemical, immunohistochemical and molecular studies in larger case groups are needed to explore origin, clinical course, therapy, and overall prognosis of this neoplasm.
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Conflicts of interest
There are no conflicts of interest.
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Department of Pathology, Selcuk University, Konya
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3]