adult-type fibrosarcoma

Digital slides

 UI: - Adult-type fibrosarcoma.
 JRC:5320 : Mammary adult-type fibrosarcoma.

Epidemiology

True fibrosarcoma is exceedingly rare, accounting for @<@1% of approximately 10,000 adult soft tissue sarcomas and should be diagnosed with great caution.

Synopsis

 sex ratio 1/1
 median age: 52.5 y (range 2 to 99 y)
 various anatomic sites

Differential diagnosis

64% of putative fibrosarcoma are reclassified, most commonly as monophasic synovial sarcoma and solitary fibrous tumor. A rearrangement of the SYT gene (synovial sarcoma) must be searched systematically.

 undifferentiated pleomorphic sarcoma
 synovial sarcoma
 solitary fibrous tumor
 myxofibrosarcoma
 malignant peripheral nerve sheath tumor
 dermatofibrosarcoma protuberans
 desmoplastic melanoma
 low-grade fibromyxoid sarcoma
 sarcomatoid carcinoma
 desmoid fibromatosis (desmoid-type fibromatosis )
 rhabdomyosarcomas
 myofibroblastic sarcoma
 spindle-cell liposarcoma
 sclerosing epithelioid fibrosarcoma
 fibroma-like epithelioid sarcoma
 leiomyosarcoma
 cellular fibrous histiocytoma

Exclusive of undifferentiated pleomorphic sarcoma, the distinction of which from fibrosarcoma is subjective, 64% of putative fibrosarcoma are reclassified, most commonly as monophasic synovial sarcoma and solitary fibrous tumor.

True fibrosarcoma is exceedingly rare, accounting for @<@1% of approximately 10,000 adult soft tissue sarcomas and should be diagnosed with great caution.

Molecular biology

 NTRK3 fusion genes in fibrosarcomas (30520818)

• NTRK fusions in malignant tumors are therapeutic targets of tyrosine kinase inhibitors.
• CD34-positive fibrosarcoma of bone and soft tissue could be a good candidate for NTRK testing.
• STRN1-NTRK3 and STRN3-NTRK fusion genes

Cytognetics

 t(2;19) (9491323)
 No consistent abnormality has been detected among the complex karyotypes.

CGH (11921284)

Gains

12q21

12q14-q15

14q22

4q22

7q31

14q23-q24

4q21

4q23-q24

8q22

12q22

 12q gains correlated with a poor outcome (11921284)

 High-level amplifications

• |12q21|18p |1p21|4q31.3|7p21|12q14-q15|Xp22.1-p22.2|Xq22-q23|

References

 Adult-type fibrosarcoma: A reevaluation of 163 putative cases diagnosed at a single institution over a 48-year period. Bahrami A, Folpe AL. Am J Surg Pathol. 2010 Oct;34(10):1504-13. PMID: 20829680

 Schmidt H, Taubert H, Wurl P, Kappler M, Lange H, Bartel F, Bache M, Holzhausen HJ, Hinze R. Gains of 12q are the most frequent genomic imbalances in adult fibrosarcoma and are correlated with a poor outcome. Genes Chromosomes Cancer. 2002 May;34(1):69-77. PMID: 11921284