Calcified fibromatosis of the neck in 4-year old girl: rapid growth, rapid therapy.

Fibromatosis is a rare soft tissue disease typical for infants and characterized by fibroblastic proliferation, which may appear similar to fibrosarcoma. An unusual case of 4-year old girl presenting large tumor of the neck with massive calcification is described. The growth of the tumor was rapid and mediastinal involvement was observed. The final diagnosis showed benign nature of tumor with microscopic features of fibromatosis calcificans. After surgical resection of neck tumor, residual mass persisted both in the neck and in the mediastinum in 6 years of follow-up without signs of progression.