Sarcoma acral myxoinflammatory fibroblastic C49.9

Locally agressively growing, fibroblastically differentiated, low malignant sarcoma of the distal extremities, which occurs mainly in adult patients.

Molecularly, a TGFBR3-MGEA5 fusion gene is characteristic (Note: this fusion gene is also detected in hemosiderotic fibrolipomatous tumor and pleomorphic hyalizing angiectatic tumor).

1,o-4.0 cm (average 2,4 cm) large, fast growing, painless firm (unspectacular), slowly increasing, swelling of the subcutaneous tenosynovial tissue of the affected region. Surgically, the tumours prove to be fuzzily limited, diffusely infiltrating and growing into the local tissue.

• Multinodular growth, moderately pleomorphic cell picture with myxoid and fibrosed, partially hyaline areas; existence of large, ganglion-like cells with prominent nucleoli; alternately strong inflammatory infiltration, predominantly from lymphocytes and histiocytes.
• Immunohistology: Vimentin+; CD68+; CD34+/-; ASMA +/-
• Molecular pathology: t(1;10), loss of chromosomes 3,13

• Inflammatory pseudotumour
• Leiomyosarcoma

There is a tendency to local recurrence. Metastases are extremely rare.

1. Ebhardt H et al (2001) [Acral myxoinflammatory fibroblastic sarcoma. Six cases of a tumor entity. Pathologist 22:157-161.