Diagnostic Studies. On MRI, tumor margins are sometimes difficult to distinguish from the normal fascial structures.

Treatment/Prognosis. Treatment of desmoids has historically been by excision or resection, but based on the extremely high recurrence rate other less invasive techniques such as tamoxifen and nonsteroidal anti-inflammatory drugs have met with some early success. Usually nonoperative treatment should at least be attempted with surgery reserved as a last resort.

FIBROMATOSIS

The term fibromatosis refers to multiple fibrous tumors that, although benign, are significantly more aggressive than solitary fibroma. These lesions often develop in the proximal limbs or the trunk and are also called abdominal and extra-abdominal desmoid tumors, depending on whether or not they involve the abdominal wall. Although generally superficial, the tumors are locally invasive, frequently involving adjacent neurovascular structures.

Diagnostic Studies. Staging studies are required for fibromatosis because of the lesions’ aggressive behavior and the need to exclude low-grade malignancy. Although the lesions usually develop adjacent to or even adherent to bone, bone scans are often cold. On CT and MRI, tumor margins are poorly demonstrated because the lesions infiltrate the surrounding fascial or fibrous structures. Histologic examination reveals scattered spindle cells enmeshed in heavy strands of mature collagen.

Treatment/Prognosis. Because the extent of involvement and the aggressiveness of fibromatosis are often underestimated, the surgical margins achieved may be inadequate as with desmoids tumors. Even if the tumors are excised with a wide margin, recurrence is likely. Recurrences are difficult to distinguish from the scarring of previous excisions, thus making subsequent excision even more difficult. Adjuvant radiation therapy may reduce the recurrence rate after marginal, or even after intracapsular, excision but has its own risk and may even cause malignant degeneration of these benign lesions.

HEMANGIOMA

Hemangioma of soft tissue is a benign, vascular tumor that occurs in children, usually in the limbs or the trunk. Sometimes, hemangioma is congenital, appearing as a solitary tumor that infiltrates local tissue and, like fibromatosis, may involve adjacent neurovascular structures. Capillary hemangiomas are noninvasive and usually smaller and more cellular than cavernous hemangiomas, which are invasive and frequently contain calcifications or phleboliths that are readily seen on radiographs. The most common form is a tumor with infiltrative margins composed of both large and small vessels.

Diagnostic Studies. On physical examination, elevating the affected body part above the level of the heart may noticeably reduce the size of the mass by emptying venous blood in the lesions. Hemangiomas have a characteristic (bull’s-eye) appearance on MRI frequently with feeding vessels, and this appearance along with the findings of the history and physical examination can frequently preclude the need for a biopsy.

Treatment/Prognosis. Despite their vascular origin, hemangiomas do not metastasize or undergo malignant transformation. However, hemangiomas frequently recur after surgical resection; therefore, injection by interventional radiology or vascular surgery has been successful and should generally be attempted, with resection as a last resort.