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Case 458 - Discussion

Uploaded: 2010-10-27, Updated: 2010-10-27

 

Fibromastosis

  • Locations:

    • Superficial: palmar (Dupuytren's disease), plantar (Ledderhose's disease)

    • Deep (Desmoid): extra-abdominal, intra-abdominal 13% a/w Gardners syndrome

  • Morphology

    • Poorly circumscribed with infiltration of adjacent tissue

    • Low to intermediate cellularity, few mitotic figures, no atypia

    • Tumor cells are spindle and uniform, containing bipolar fibroblasts and myofibroblasts

    • Stroma: collagenous, keloid or myxoid

    • Elongate blood vessels with paralleling myofibroblasts and perivascular lymphocytes at edge of lesion

  • Beta catenin + (nuclear), variable SMA, MSA and CD117

  • S100-, CD34-

  • Mutations in the Wnt/beta-catenin (APC-beta-catenin-Tcf) pathways; somatic beta-catenin point mutations in exon 3, codon 41 or codon 45 in 87%

  • 50% recur, no metastasis, but can be fatal