@entity84 is a rare, benign @entity3478 . Although it has distinctive clinicopathologic features, its wide morphologic spectrum may pose diagnostic problems. We present the clinicopathologic features of 42 @entity1 (28 males, 14 females; age range, 8 to 66 years), with emphasis on unusual histologic features, potential diagnostic pitfalls, and factors associated with recurrence. Thirty-four @entity5 were in long bones, with the most common site being the proximal femur. Unusual histologic features included the presence of atypical, epithelioid, spindle, and foamy cells and @entity39 and a diffuse basophilic myxoid matrix. @entity5 with focal osteoclast-like giant cell rich areas (n = 11), prominent cystic change (n = 8) and extensive fibromyxoid areas (n = 3) resembled @entity2967 , @entity80 , and chondromyxoid @entity81 , respectively. The diagnosis of referring pathologists was inaccurate in 34% of cases. Six @entity1 (14%) had local recurrence. The only clinical feature significantly associated with increased risk of local recurrence was duration of symptoms for less than 6 months (log rank P =.003). None of the histologic features was significantly associated with recurrence. These included worrisome features such as @entity465 , @entity39 , and mitoses. None of the @entity1 had @entity3 . An increased awareness of the morphologic spectrum of @entity84 will enable pathologists to avoid diagnostic pitfalls. We emphasize the need for a combined clinical, radiologic and histologic approach to the diagnosis of @entity84 .

XXXX : varied histologic appearance, potential diagnostic pitfalls, and clinicopathologic features associated with local recurrence.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity39 :: ('MESH:D009336', 'Disease') :: ['necrosis'] @entity5 :: ('MESH:D009369', 'Disease') :: ['Tumors', 'tumors'] @entity3478 :: ('MESH:D001859', 'Disease') :: ['bone tumor'] @entity2967 :: ('MESH:D005870', 'Disease') :: ['giant cell tumors'] @entity465 :: ('MESH:D007153', 'Disease') :: ['cellular atypia'] @entity80 :: ('MESH:D017824', 'Disease') :: ['aneurysmal bone cysts'] @entity84 :: ('MESH:D002804', 'Disease') :: ['Chondroblastoma', 'chondroblastomas'] @entity3 :: ('MESH:D009362', 'Disease') :: ['metastases'] @entity81 :: ('MESH:D005350', 'Disease') :: ['fibromas']
@entity84 :: (MESH:D002804,Disease) :: ['Chondroblastoma']
