bubble_chart Overview

Benign fibrous histiocytoma is a benign tumor originating from histiocytes, similar to histiocytoma fibrosum and giant cell tumor of bone.

bubble_chart Pathological Changes

1. Gross examination: The periosteum and paracortical connective tissue appear normal to the naked eye. The cortical bone is thinned but continuous. The tumor is dense, composed of gelatinous material or small amounts of fibrous-like substance, presenting a leathery yellow appearance, occasionally with bright yellow speckles. Adjacent to this tissue, there may be softer areas that are light brown or pale reddish-brown, resembling a giant cell tumor of bone. The tumor exhibits clear demarcation from the surrounding bone.

2. Microscopic examination: The tissue is highly cellular with collagen arranged in whorled or laminated patterns. The cells possess round-to-oval nuclei, which may elongate along the fiber direction. Abundant large foamy cells are present, either isolated or in clusters. Multinucleated giant cells are sparse and small, with mitotic figures being rare. In certain regions (corresponding to the gross pathological areas resembling giant cell tumor of bone), structures identical to those of a giant cell tumor of bone can be observed.

bubble_chart Clinical Manifestations

The disease is rare, with only a few cases reported so far, making it difficult to provide accurate statistics on gender, age, and location. It typically occurs in adults and is most commonly found in the metaphysis of long bones. It has also been observed in the sacrum, ilium, and mandible.

Symptoms include persistent moderate pain and swelling.

bubble_chart Auxiliary Examination

X-ray findings show osteolytic lesions located in the metaphysis of long bones, presenting as round and eccentric, sometimes demarcated by a thin sclerotic line, with thinning of the cortex and occasional grade I expansion. In smaller bones, such as the fibular head, the lesion may occupy the entire segment, and sometimes partial cortical bone may disappear, but there is no periosteal reaction.

bubble_chart Treatment Measures

Surgical treatment. Since benign fibrous histiocytoma is generally classified as stage II (active) in benign tumors, curettage is employed and can be combined with local adjuvants. If the resection is thorough, it is usually curable.

bubble_chart Differentiation

It needs to be differentiated from non-ossifying fibroma and giant cell tumor of bone.