Osteofibrous dysplasia and adamantinoma

Osteofibrous dysplasia (OFD) is a rare, benign, fibro-osseous lesion that typically is seen within the cortex of the tibia in children. Adamantinoma (AD) is a rare, low-grade malignant primary bone tumor that occurs most often in the tibia and/or fibula of adolescent persons and young adults; however, it has been reported in other long bones, as well. Immunohistochemical and ultrastructural evidence has shown that the neoplastic cell in AD derives from an epithelial lineage. More recently, published reports have described another clinical entity-differentiated or OFD-like AD-that appears to lie between OFD and AD along a spectrum of disease. Controversy exists as to whether OFD is a precursor lesion to AD or whether OFD may be a residual lesion resulting from a spontaneously regressing AD. Management of OFD varies from observation to surgical intervention, depending on the age of the patient and the extent of the lesion. Management of AD requires surgical resection with wide margins, followed by appropriate reconstruction, to minimize the risk of local recurrence or metastasis

Giant Cell Tumor of Bone: Risk Factors for Recurrence

Many surgeons treat giant cell tumor of bone (GCT) with intralesional curettage. Wide resection is reserved for extensive bone destruction where joint preservation is impossible or when expendable sites (eg, fibular head) are affected. Adjuvants such as polymethylmethacrylate and phenol have been recommended to reduce the risk of local recurrence after intralesional surgery. However, the best treatment of these tumors and risk factors for recurrence remain controversial

Recurrent Giant Cell Tumor of Long Bones: Analysis of Surgical Management

Treatment of giant cell tumor of bone (GCT) often is complicated by local recurrence. Intralesional curettage is the standard of care for primary GCTs. However, there is controversy whether intralesional curettage should be preferred over wide resection in recurrent GCTs

Multiple glomus tumors of the lower leg

Glomus tumors are rare, usually solitary lesions, most commonly presenting as a painful nodule in the subungual location of the digits. Glomus tumors have been reported in multiples and can be found in atypical locations, including the lower leg. We describe sonographic and magnetic resonance imaging (MRI) findings in a patient with multiple glomus tumors of the lower leg

RT-PCR Analysis for FGF23 Using Paraffin Sections in the Diagnosis of Phosphaturic Mesenchymal Tumors With and Without Known Tumor Induced Osteomalacia

Phosphaturic mesenchymal tumors of the mixed connective tissue type (PMTMCT) are extremely rare, histologically distinctive neoplasms, which cause tumor-induced osteomalacia (TIO) in most cases through the elaboration of a phosphaturic hormone, fibroblast growth factor-23 (FGF23). Rarely, identical tumors without known TIO may be observed. We Studied a large group of PMTMCT for expression of FGF23, using a novel reverse transcription polymerase chain reaction (RT-PCR) assay for FGF23 in formalin-fixed, paraffin-embedded tissues. Twenty-nine PMTMCT (17 with and 12 without TIO) and 23 non-PMTMCT (16 various mesenchymal tumors, including 5 chondromyxoid fibroma, 8 chondroblastoma, I hemangiopericytoma, I aneurysmal bone cyst, and I high grade sarcoma; 5 carcinomas; and 2 non-neoplastic tissues) were retrieved. Total RNA was extracted from formalin-fixed, paraffin-embedded sections for RT-PCR analysis. FGF23 was amplified using 3 sets of primers that spanned the intron/exon boundaries,to amplify the 3 exons of FGF23 gene (140, 125, and 175 bp). The housekeeping gene phosphoglycerokinase (189 bp) was coamplified to check the RNA quality. Sixteen of 17 (94%) PMTMCT with TIO were FGF23-positive. Nine of 12 (75%) PMTMCT Without TIO were FGF23-positive. Two chondromyxoid fibroma and I aneurysmal bone cyst were positive; all other non-PMTMCT were negative. We conclude that RT-PCR for FGF23 is a sensitive and specific means of confirming the diagnosis of PMTMCT both in patients with and without TIO. FGF23 gene expression was present in more than 90% of PMTMCT with known TIO, confirming the role of FGF23 in this syndrome. Rare FGF23-negative PMTMCT with known TIO likely express other phosphaturic hormones (eg, frizzled-related protein 4). Our finding of expression of FGF23 in 75% of histologically identical tumors without known TIO confirms the reproducibility of the diagnosis of PMTMCT, even in the absence of known phosphaturia

USP6 and CDH11 Oncogenes Identify the Neoplastic Cell in Primary Aneurysmal Bone Cysts and Are Absent in So-Called Secondary Aneurysmal Bone Cysts

Aneurysmal bone cyst (ABC) is a locally recurrent bone lesion that has been regarded as a reactive process. Recently, a neoplastic basis in primary ABC was evidenced by demonstration of clonal chromosome band 17p13 translocations that place the USP6 (TRE2 or TRE17) oncogene under the regulatory influence of the highly active CDH11 promoter. Herein, we report CDH11 and/or USP6 rearrangements in 36 of 52 primary ABCs (69%), of which 10 had CDH11-USP6 fusion, 23 had variant USP6 rearrangements without CDH11 rearrangement, and three had variant CDH11 rearrangements without USP6 rearrangement. USP6 and CDH11 rearrangements were restricted to spindle cells in the ABC and were not found in multinucleated giant cells, inflammatory cells, endothelial cells, or osteoblasts. CDH11 and USP6 rearrangements did not correlate with recurrence-free survival, or with other clinicopathological features. CDH11 and USP6 rearrangements were not found in any of 17 secondary ABC associated with giant cell tumor, chondroblastoma, osteoblastoma, and fibrous dysplasia. These findings demonstrate that primary ABC are mesenchymal neoplasms exhibiting USP6 and/or CDH11 oncogenic rearrangements. By contrast, secondary ABC lack CDH11 and USP6 rearrangements, and although morphological mimics of primary ABC, appear to represent a non-specific morphological pattern of a diverse group of non-ABC neoplasms