Differential diagnostic value of "blue reticulated chondroid-like material" in aneurysmal bone cysts: a classic histopathologic analysis of 215 cases.

Objectives: Our classic histopathologic study of aneurysmal bone cyst (ABC) revealed that "blue reticulated chondroid-like material" (BRC) is characteristic of ABC.

Methods: The light microscopic findings were retrospectively analyzed in 215 cases of ABC, including 101 primary and 114 secondary cases. In addition, 22 cases of telangiectatic osteosarcoma (TOS) were drawn from the same source and used as a control.

Difficulty distinguishing benign notochordal cell tumor from chordoma further suggests a link between them.

Background: Much discussion about benign notochordal cell tissue in vertebrae has centered on the nature of its relationship, if any, to chordoma. Often referred to as benign notochordal cell tumors (BNCTs), these lesions have unique morphological features, however, differentiating between notochordal cells in discs, BNCT, and chordoma can be difficult. They are described as radiologically distinct from chordoma, with lysis, contrast enhancement, and a soft tissue mass indicating chordoma.

Enchondroma vs. chondrosarcoma: a simple, easy-to-use, new magnetic resonance sign.

Introduction: There is no clear radiologic or pathologic agreement on the differences between enchondroma and conventional chondrosarcoma, which has huge therapeutic consequences. Microscopically, an enchondroma is composed of "islands of intramedullary hyaline cartilage surrounded by marrow fat", and a chondrosarcoma a "diffuse cartilaginous replacement (invasion) of the marrow which leads to complete 'trapping' of host lamellar bone trabeculae." The marrow around islands of cartilage should be detectable on magnetic resonance imaging (MR).

Painful metal-on-metal total hip arthroplasty.

Two patients were evaluated for the possibility of hypersensitivity to a Metasul articulation (Centerpulse, Austin, Tex) coupled with total hip arthroplasty. Serum was tested with a lymphocyte proliferation assay, and the capsular tissues from the hip were examined for perivascular lymphocytes. The diagnosis of hypersensitivity to Metasul could not be confirmed in these patients, and ultimately, the painful hip arthroplasties were felt to be caused by a combination of musculoskeletal problems.

Pigmented villonodular synovitis of the foot and ankle.

Background: Pigmented villonodular synovitis (PVNS) is a rare disease of uncertain etiology usually affecting the synovium of weightbearing joints.

Methods: We retrospectively evaluated 11 patients who were diagnosed and treated for PVNS of the ankle and foot over a 13-year period with a minimum of 2-year followup. Four patients with ankle joint PVNS and one patient with PVNS of the fifth metatarsophalangeal joint were seen initially at our institution and were treated with surgery alone.