title: Solitary fibrous tumor of the orbit: morphological, cytogenetic and molecular features.
abstract: Solitary fibrous tumor (SFT), a benign neoplasm arising in mesenchymal structures, was initially described in the pleura but subsequently has also been documented in other locations. It is uncommon in the orbit, where it closely resembles other benign spindle-shaped mesenchymal tumors of this area such as schwannoma, meningioma or hemangiopericytoma. We present a case of orbital SFT in a 34-year-old woman. The radiological study showed the presence of an enhanced uptake lesion measuring 2 cm in major diameter. The histopathological evaluation revealed alternating cellular and hypocellular areas with spindle-shaped cells. The cellular organization displayed a broad variety of irregular morphological patterns. The neoplastic cells were intensely positive for CD34 and vimentin, while S100, epithelial membrane antigen (EMA), Caldesmon, Calretinin and WT-1 proved negative. The pericellular matrix exhibited strong positivity for CD44 and collagen IV. Scarce mitotic figures, a Ki-67 nuclear labeling index of <5%, and focal expression of p53 were also observed. Measurement of DNA content revealed a DNA index of 1, indicating a diploid peak in 95% of the tumor cells. A normal 46,XX karyotype was present. No TP53 (exons 5-8) mutations or MDM2 and CDK4 amplifications were observed. No p14(ARF), p15(INK4B) and p16(INK4A) deletions or hypermethylation were observed in this benign tumor. Following surgical resection and radiotherapy, the patient showed no tumor relapse after one year of follow-up.
authors.affiliation: Department of Pathology, Valencia University, Valencia University Clinic Hospital, Valencia, Spain. jose.m.cerda@uv.es
authors.forename: Miguel
authors.initials: M
authors.lastname: Cerdá-Nicolás
authors.forename: Concha
authors.initials: C
authors.lastname: Löpez-Gines
authors.forename: Rosario
authors.initials: R
authors.lastname: Gil-Benso
authors.forename: Rafael
authors.initials: R
authors.lastname: Benito
authors.forename: Antonio
authors.initials: A
authors.lastname: Pellin
authors.forename: Amparo
authors.initials: A
authors.lastname: Ruiz-Saurí
authors.forename: Juan
authors.initials: J
authors.lastname: Sanchos-Garcia
authors.forename: Pedro
authors.initials: P
authors.lastname: Roldan
authors.forename: Fernando
authors.initials: F
authors.lastname: Talamantes
authors.forename: José
authors.initials: J
authors.lastname: Barberá
mesh_terms: D000328:Adult; D050762:Cyclin-Dependent Kinase Inhibitor p15 / Q000235:genetics; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics; D019175:DNA Methylation; D005091:Exons / Q000235:genetics; D005260:Female; D005350:Fibroma / Q000235:genetics* / Q000473:pathology*; D017353:Gene Deletion; D016158:Genes, p53 / Q000235:genetics; D006801:Humans; D008279:Magnetic Resonance Imaging; D009918:Orbital Neoplasms / Q000235:genetics* / Q000473:pathology*; D017354:Point Mutation; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics; D012983:Soft Tissue Neoplasms / Q000235:genetics / Q000473:pathology; D025803:Tumor Suppressor Protein p14ARF / Q000235:genetics
chemical_list: D050762:Cyclin-Dependent Kinase Inhibitor p15; D019941:Cyclin-Dependent Kinase Inhibitor p16; D025803:Tumor Suppressor Protein p14ARF; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2