title: Nuclear beta-catenin expression distinguishes deep fibromatosis from other benign and malignant fibroblastic and myofibroblastic lesions.
abstract: Deep fibromatoses (desmoid tumors) are clonal myofibroblastic proliferations that are prone to aggressive local recurrences but that do not metastasize. They must be distinguished from a host of fibroblastic and myofibroblastic lesions as well as from smooth muscle neoplasms. Virtually all deep fibromatoses have somatic beta-catenin or adenomatous polyposis coli (APC) gene mutations leading to intranuclear accumulation of beta-catenin. Since low-grade sarcomas in general lack beta-catenin and since reactive proliferations would not be expected to have it, we predicted that nuclear beta-catenin expression would be detected in deep fibromatoses but absent in other entities in the differential diagnosis. We evaluated the role of beta-catenin to help differentiate distinguish deep fibromatoses from congeners. Formalin-fixed, paraffin-embedded sections from 21 lesions from 20 patients with deep fibromatoses were stained with monoclonal beta-catenin antibody (Transduction Laboratories) and compared with low-grade fibromyxoid sarcoma (n=12), leiomyosarcoma (n=10), various other fibrosarcoma variants (n=13, including 3 myofibrosarcomas, 3 sclerosing epithelioid fibrosarcomas, 5 low-grade fibrosarcomas, 1 classic fibrosarcoma arising in dermatofibrosarcoma protuberans, 1 inflammatory myxohyaline tumor/myxoinflammatory fibroblastic sarcoma), myofibroma/myofibromatosis (n=12), nodular fasciitis (n=11), and scars (n=9). Nuclear and cytoplasmic staining was assessed. All 21 examples of deep fibromatosis displayed nuclear beta-catenin (focal nuclear staining in one case to 90% staining). All other lesions tested (n=67) lacked nuclear labeling for beta-catenin, showing only cytoplasmic accumulation. beta-Catenin immunohistochemistry separates deep fibromatosis from entities in the differential diagnosis, a finding that can be exploited for diagnosis. Most fibromatoses have diffuse nuclear staining although occasional examples only focally label.
authors.affiliation: Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA.
authors.forename: Baishali
authors.initials: B
authors.lastname: Bhattacharya
authors.forename: Harrison Parry
authors.initials: HP
authors.lastname: Dilworth
authors.forename: Christine
authors.initials: C
authors.lastname: Iacobuzio-Donahue
authors.forename: Francesca
authors.initials: F
authors.lastname: Ricci
authors.forename: Kristin
authors.initials: K
authors.lastname: Weber
authors.forename: Mary A
authors.initials: MA
authors.lastname: Furlong
authors.forename: Cyril
authors.initials: C
authors.lastname: Fisher
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Montgomery
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism / Q000473:pathology*; D002648:Child; D002921:Cicatrix / Q000378:metabolism / Q000473:pathology; D003593:Cytoplasm / Q000378:metabolism / Q000473:pathology; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D003937:Diagnosis, Differential; D005208:Fasciitis / Q000378:metabolism / Q000473:pathology; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology*; D018221:Fibromatosis, Abdominal / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012509:Sarcoma / Q000378:metabolism / Q000473:pathology*; D015534:Trans-Activators / Q000378:metabolism*; D051176:beta Catenin
chemical_list: D014408:Biomarkers, Tumor; C495270:CTNNB1 protein, human; D003598:Cytoskeletal Proteins; D015534:Trans-Activators; D051176:beta Catenin