Myxofibrosarcoma is rare Soft fabric tumor, which usually occurs on the shoulder girdle of the elderly. Is a evil one tumor with high risk of local reappearance.
Histology myxofibrosarcoma
Myxofibrosarcoma presents as a multinodular tumor, with a variable cellular spindle cell proliferation in a myxoid background (figures 1, 2). Mobile atypia with nuclear pleomorphism and expanded hyperchromatic nuclei it is seen at least focally (figure 3). The characteristic feature is the presence of delicate curvilinear vessels (Figures 4,5).
Figure 1
Figure 2
figure 3
The rating falls on a spectrum based on the interpretation of cellularity.
- Low grade: hypocellular without solid zones
- Intermediate grade: myxoid with greater cellularity.
- High grade: solid tumor with prominent pleomorphism (Figures 6.7)
Figure 4
Figure 5
Figure 6
Special stains
Usually immunohistochemistry It is not useful in myxofibrosarcoma, but is positive for vimentin, and sometimes weakly positive for smooth muscle actin and CD34.
Variants of myxofibrosarcoma
Epithelioid: Cell areas morphologically epithelioid behave as high-grade, and are prone to increased local recurrence and risk of metastasis.
Figure 7
Figure 8
Figure 9
Differential diagnosis
Low-grade fibromyxoid sarcoma: Typically paucicellular with alternate fibrous and myxoid areas. Nuclear pleomorphism is mild or absent.
Myxoid liposarcoma: This tumor has lipoblasts and lacks significant pleomorphism. Vacuoles within lipoblasts will be clear, unlike myxofibrosarcoma, where vacuoles typically contain fine myxoid material (pseudolipoblasts) (Figures 8,9). Genetics will show a t (12; 16) or t (12; 22) translocation, while MDM2 is frequently negative.
Myxoid dermatofibrosarcoma protuberans: stormy pattern with positive CD34 immunostaining.
Malignant fibrous histiocytoma: this entity behaves and is probably synonymous with high-grade myxofibrosarcoma.
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