Fibroma of tendon sheath

The Sehnenscheidenfibrom ( tenosynoviales fibroid) is a benign nodular formation, often clinging to a tendon or tendon sheath or arises at least in their vicinity. Typically affected are particular fingers, especially the thumb, index and middle fingers. Rarely the tumor within joints (knee, elbow, wrist ) has been described.

Epidemiology

The Sehnenscheidenfibrom is usually observed between 20 and 50 years old, with the peak age is in the fourth decade of life. Men are slightly more often affected than women (3: 2).

Clinic

Clinically, it is a usually small painless tumor formation with slow growth. However, nerve compression, carpal tunnel syndrome and pain may occur.

Pathology

Macroscopy

Macroscopically there is a sharply defined, lobulated or mehrknotigen tumor with a size of typically less than 2 cm and almost always less than 3 cm. The cut surface is homogeneous whitish and solid.

Histology

Histologically, show well-circumscribed nodules, which are often separated by deep, narrow fabric columns. The tumor tissue is usually poor in cells and is composed of spindle-shaped fibroblasts and myofibroblasts in a collagenous fibrous stroma. Characteristic are present scattered elongated slit-shaped vascular spaces. Section, a higher cell density is possible, especially in the peripheral area of the lesion - the image here may be similar to a nodular fasciitis. There are usually no significant cellular atypia or mitoses.

Less common features include the occurrence of star-shaped cells, pleomorphic bizarre cells, myxoid change, cyst formation, dense hyalinization and a chondroid or osseous metaplasia.

Immunohistochemistry

Often a part of the cell elements shows an expression of smooth muscle actin. In addition, the tumor cells are positive for Vimentin. In a few cases, CD34 positivity has been reported. The macrophage antigens CD68 and CD163 can be expressed focally. The marker desmin, S100 and beta -catenin are negative.

Differential Diagnosis

The Sehnenscheidenfibrom must be clinical and histological distinction of benign lesions such as giant cell tumor tenosynovial, the Einschlusskörperchenfibromatose, nodular fasciitis, the desmoplastic fibroblastoma, the palmar and plantar fibromatosis and benign fibrous histiocytoma.

Forecast

After surgical removal of the lesion recur up to one quarter of the tumors, sometimes repeatedly. This may be due to that the distance due to the adhesion of tumor tissue can be difficult to chord structures. Relapses must be inspected by a renewed engagement in the rule. A metastasis does not occur.