Ossifying fibromyxoid tumour of soft parts, with focus on unusual clinicopathological features.
OBJECTIVE
Ossifying fibromyxoid tumour is a rare lesion that generally occurs in the soft tissues of proximal limbs/girdle, or head and neck. Histologically, it usually consists of bland, mitotically inactive, S100+ cells in a fibromyxoid matrix with a characteristic peripheral ossification. However, we present two cases that deviated from this pattern.


METHODS
One tumour, which was removed from the axilla of a 55-year-old female, was unusual in its large size (120 mm in diameter) and in its restriction of bone formation to its central zones. The other tumour, which occurred in a 62-year-old female, was remarkable in its acral location on the hand and high mitotic activity (four mitoses per high-power field). These features caused concern and follow-up of the patients was recommended. So far there have been no recurrences (25 and 18 months after surgery, respectively). An additional previously undescribed feature was the presence of fibronexus-like structures by electron microscopy in the second case. However, a myofibroblastic phenotype was not supported by the immunohistochemical findings.


CONCLUSIONS
Though a distinct entity, ossifying fibromyxoid tumour may exhibit a wider clinicopathological spectrum than generally recognized.
Holck
S
S
Department of Pathology, Hillerød Sygehus, Hillerød, Denmark. suhol@fa.dk
Pedersen
J G
JG
Ackermann
T
T
Daugaard
S
S
D014408:Biomarkers, Tumor / Q000378:metabolism; D005260:Female; D005350:Fibroma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007150:Immunohistochemistry; D007382:Intermediate Filaments / Q000648:ultrastructure; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis; D009999:Ossification, Heterotopic / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D012983:Soft Tissue Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D016896:Treatment Outcome
D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins