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| |} | | |} |
| ==Definition / Description of Disease== | | ==Definition / Description of Disease== |
− | Put your text here <span style="color:#0070C0">(''Instructions: Brief description of approximately one paragraph - include disease context relative to other WHO classification categories, diagnostic criteria if applicable, and differential diagnosis if applicable. Other classifications can be referenced for comparison.'') </span>
| + | Solitary fibrous tumor (SFT) is a mesenchymal spindle cell neoplasm that can develop at any site in the body, including soft tissue, visceral organs, bone, etc. It was first described by Klemperer and Rabin in 1992 as a tumor of the pleura. However, since then this entity has been increasingly described from extrapleural sites. A morphologic clue to the diagnosis is the distinctive branching “staghorn” vessels. SFT is characterized by ''NAB2::STAT6'' fusion resulting from a paracentric inversion at chromosome 12q13q13. |
| ==Synonyms / Terminology== | | ==Synonyms / Terminology== |
− | Put your text here <span style="color:#0070C0">(''Instructions: Include currently used terms and major historical ones, adding “(historical)” after the latter.'') </span>
| + | Formerly SFTs were categorized as hemangiopericytomas. |
| ==Epidemiology / Prevalence== | | ==Epidemiology / Prevalence== |
− | Put your text here
| + | SFT occurs most commonly in adults with no gender predilection. Incidence of the tumor is highest in the age group of 40-70 years. |
| ==Clinical Features== | | ==Clinical Features== |
− | Put your text here and fill in the table <span style="color:#0070C0">(''Instruction: Can include references in the table. Do not delete table.'') </span>
| + | <br /> |
| {| class="wikitable" | | {| class="wikitable" |
| |'''Signs and Symptoms''' | | |'''Signs and Symptoms''' |
− | |<span class="blue-text">EXAMPLE:</span> Asymptomatic (incidental finding on complete blood counts) | + | |SFTs present as slow-growing, painless neoplasms. Clinical symptoms can be due to mass effect in the site of involvement. |
− | <span class="blue-text">EXAMPLE:</span> B-symptoms (weight loss, fever, night sweats)
| + | e.g. Abdomen/Pelvis: abdominal distention, constipation, urinary retention |
| | | |
− | <span class="blue-text">EXAMPLE:</span> Lymphadenopathy (uncommon)
| + | Head/Neck: Dysphonia, nasal obstruction, dysphagia |
| |- | | |- |
| |'''Laboratory Findings''' | | |'''Laboratory Findings''' |
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| |} | | |} |
| ==Sites of Involvement== | | ==Sites of Involvement== |
− | Put your text here <span style="color:#0070C0">(''Instruction: Indicate physical sites; <span class="blue-text">EXAMPLE:</span> nodal, extranodal, bone marrow'') </span>
| + | SFTs may occur at any site of the body. Involvement of head and neck, deep soft tissues, abdominal cavity, retroperitoneum, pelvis, bone, and visceral organs have been reported. |
| ==Morphologic Features== | | ==Morphologic Features== |
− | Put your text here <span style="color:#0070C0">(''Instructions: Brief description of typically approximately one paragraph'') </span>
| + | Morphologically, biopsy or resection specimens will show a bland spindle cell proliferation arranged haphazardly in a background of collagenous stroma. Cells contain ovoid nuclei within eosinophilic cytoplasm with indistinct cell borders. Tumors can vary in cellularity and stromal collagen. On low power, branching, “staghorn” shaped vessels can often be appreciated. Mitotic counts are usually low. Myxoid and lipomatous change have been described. SFT with adipocytic component are referred to as fat-forming (lipomatous) SFTs. There is also a variant known as giant cell rich SFT, which has the classic patternless spindle cell proliferation admixed with multinucleated giant cells. Dedifferentiated SFTs will show conventional SFT transitioning to a high-grade pleomorphic variant. Heterologous elements may be present. Standard immunophenotypic expression of CD34 and STAT6 is often lost in the dedifferentiated component. |
| ==Immunophenotype== | | ==Immunophenotype== |
| Put your text here and fill in the table <span style="color:#0070C0">(''Instruction: Can include references in the table. Do not delete table.'') </span> | | Put your text here and fill in the table <span style="color:#0070C0">(''Instruction: Can include references in the table. Do not delete table.'') </span> |
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| !Finding!!Marker | | !Finding!!Marker |
| |- | | |- |
− | |Positive (universal)||<span class="blue-text">EXAMPLE:</span> CD1 | + | |Positive (universal)||CD34 |
| |- | | |- |
− | |Positive (subset)|| | + | |Positive (universal)||STAT6 |
| |- | | |- |
| |Negative (universal)|| | | |Negative (universal)|| |