A 51-year-old woman complained of an enlarging 4 cm mass on the dorsum of the foot, which was found to infiltrate the extensor tendon sheath. Local excision was performed. The patient suffered two subsequent recurrences.

Pathologic Findings The lesion consists of a complex admixture of spindle cells and mature adipocytes, both of which form part of the excised mass. The lesional spindle cells ramify between adipocytes and around stromal blood vessels, focally being associated with a patchy lymphocytic infiltrate. The spindle cells have bland tapering nuclei and eosinophilic cytoplasm. Multifocally, there is stromal haemosiderin deposition, mainly in the spindle cell areas. The admixed inflammatory cells consist predominantly of lymphocytes with small numbers of plasma cells and histiocytes. There are just very rare lesional cells with mildly atypical plump vesicular nuclei. By immunohistochemistry, the spindle cells are immunopositive for CD34.

HAEMOSIDEROTIC FIBROLIPOMATOUS TUMOUR