Liposarcoma pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]
Overview
Pathogenesis
According to their class, each liposarcoma will have specific characteristics and pathogenesis:
Well Differentiated Liposarcoma
This type of liposarcoma occurs both at the limbs and retroperitoneum in equal frequency, and occasionally at the mediastinum and spermatic cord, representing about 45% of liposarcomas.[1]
According to the WHO classification described previously, well differentiated liposarcomas may be sub-classified into 3 types: sclerosing; adipocytic; and inflammatory.
Sclerosing Liposarcoma
Occurs most frequently at the retroperitoneum and paratesticular regions. The particular histological finding in this type of well differentiated liposarcoma is the identification of distinctive stromal cells distributed across the tissue, and associated with lipoblasts filled with multiple vacuoles. This association forms a collagenous background of fibrillary appearance. In certain cases the fibrous component of the neoplasm may occupy most of its mass.[1]
Adipocytic Liposarcoma
Frequently composed by adipocytes with different cell sizes, hyperchromasia and nuclear atypia. Fibrous septa may be identified among adipocytes, containing hyperchromatic stromal cells. Besides these two types of cells, mono or multivacuolated lipoblasts may also be identified. These last are characterized by the presence of single (mono) or multiple (multi) peripheral cytoplasmic vacuoles that press on the hyperchromatic nucleus.[1]
In general, adipocytic neoplasms are often identified by the presence of these lipoblasts, however, its presence is not synonym, since multiple benign lesions may contain lipoblasts; nor are they identified in every liposarcoma, as its absence does not prevent the diagnosis of the condition, if remaining criteria are met.[1]
Inflammatory Liposarcoma
Its adipocitic nature may be misidentified due to the heavy chronic inflammatory infiltrate. The inflammatory component is frequently composed of different lympho-plasmacytic aggregates. These tend to be predominantly formed by a specific type of B-cell yet, T-cells may in some cases populate the inflammatory aggregate.[1][2][3] For the diagnosis of inflammatory liposarcoma a large sample is required to avoid missing the adipocitic component of the neoplasm.[1]
Spindle cell lipocarcinoma is a rare adult type of well-differentiated liposarcoma. It results from the proliferation of neural-like spindle cells, organized in a fibrous structure, containing lipoblasts.[4][5]
Dedifferentiated Liposarcoma
Myxoid Liposarcoma
Round Cell Liposarcoma
Pleomorphic Liposarcoma
Genetics
Well-Differentiated Liposarcoma
Specific diagnostic techniques, such as karyotipic analysis, have showed a specific characteristic of these cells, namely the presence of a large marker chromosome and/or of an extra ring.[6] With the help of in situ hybridization, these rings and/or large markers were noted to accommodate amplified genetic sequences of the 12q13-15 chromosome region.[7]
Associated Conditions
Gross Pathology
Microscopic Pathology
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Dei Tos AP (2000). "Liposarcoma: new entities and evolving concepts". Ann Diagn Pathol. 4 (4): 252–66. doi:10.1053/adpa.2000.8133. PMID 10982304.
- ↑ Kraus MD, Guillou L, Fletcher CD (1997). "Well-differentiated inflammatory liposarcoma: an uncommon and easily overlooked variant of a common sarcoma". Am J Surg Pathol. 21 (5): 518–27. PMID 9158675.
- ↑ Argani P, Facchetti F, Inghirami G, Rosai J (1997). "Lymphocyte-rich well-differentiated liposarcoma: report of nine cases". Am J Surg Pathol. 21 (8): 884–95. PMID 9255251.
- ↑ Dei Tos AP, Mentzel T, Newman PL, Fletcher CD (1994). "Spindle cell liposarcoma, a hitherto unrecognized variant of liposarcoma. Analysis of six cases". Am J Surg Pathol. 18 (9): 913–21. PMID 8067512.
- ↑ Hendrickson WA, Ward KB (1975). "Atomic models for the polypeptide backbones of myohemerythrin and hemerythrin". Biochem Biophys Res Commun. 66 (4): 1349–56. PMID 5.
- ↑ Rosai J, Akerman M, Dal Cin P, DeWever I, Fletcher CD, Mandahl N; et al. (1996). "Combined morphologic and karyotypic study of 59 atypical lipomatous tumors. Evaluation of their relationship and differential diagnosis with other adipose tissue tumors (a report of the CHAMP Study Group)". Am J Surg Pathol. 20 (10): 1182–9. PMID 8827023.
- ↑ Dal Cin P, Kools P, Sciot R, De Wever I, Van Damme B, Van de Ven W; et al. (1993). "Cytogenetic and fluorescence in situ hybridization investigation of ring chromosomes characterizing a specific pathologic subgroup of adipose tissue tumors". Cancer Genet Cytogenet. 68 (2): 85–90. PMID 8353809.