Prevalence and characteristics of benign cartilaginous tumours of the knee joint as identified on MRI scans.

BACKGROUND: Enchondromas (EC) and atypical cartilaginous tumours (ACT) of the knee joint represent benign/intermediate chondromatous neoplasms of the bone that are most commonly discovered incidentally. Based on small to intermediate-sized cohorts, the prevalence of cartilaginous tumours of the knee as visible in MRI is estimated at 0.2-2.9%. This study aimed at verifying/challenging these numbers via retrospective examination of a larger, uniform patient cohort. METHODS: Between 01.01.2007 and 01.03.2020, 44,762 patients had received an MRI of the knee for any indication at a radiologic centre. Of these, 697 patients presented with MRI reports positive for cartilaginous lesions. In a three-step workflow, 46 patients were excluded by a trained co-author, a radiologist and an orthopaedic oncologist, as wrongly being diagnosed for a cartilage tumour. RESULTS: Of 44,762 patients, 651 presented with at least one EC/ACT indicating a prevalence of 1.45% for benign/intermediate cartilaginous tumours of the knee joint (EC: 1.4%; ACTs: 0.05%). As 21 patients showed 2 chondromatous lesions, altogether 672 tumours (650 ECs [96.7%] and 22 ACTs [3.3%]) could be analysed in terms of tumour characteristics: With a mean size of 1.6 ± 1.1 cm, most lesions were located in the distal femur (72.9%), in the metaphysis of the respective bone (58.9%) and centrally in the medullary canal (57.4%). CONCLUSIONS: This study revealed an overall prevalence of 1.45% for cartilage lesions around the knee joint. Whilst a constant increase in prevalence was found for ECs over 13.2 years, prevalence remained constant for ACTs.

The Natural History of Benign Bone Tumors of the Extremities in Asymptomatic Children: A Longitudinal Radiographic Study.

BACKGROUND: Benign bone tumors are common incidental findings in the pediatric population during radiographic evaluation. Counseling these patients requires reassurance and raises questions about the natural history of these tumors over time. The purpose of this study was to estimate the prevalence and observe the behavior of benign childhood bone tumors in an asymptomatic population. METHODS: A historical, longitudinal radiographic collection of healthy children was reviewed, which included comprehensive left-sided radiographs of the extremities at yearly intervals. In this study, 262 subjects with 25,555 radiographs were screened for benign bone tumors at a median age of 8 years (range, 0 to 18 years). All potential tumors were reviewed by a multidisciplinary panel, which confirmed the radiographic diagnosis of each lesion, the age at which the lesion first appeared, and the age at which it had resolved. Prevalence rates were calculated using the number of distinct subjects available for each radiographic location and age. RESULTS: Thirty-five tumors were identified in 33 subjects, including 19 nonossifying fibromas, 8 enostoses, 6 osteochondromas, and 2 enchondromas. The prevalence rate for all tumors combined increased with age and was 18.9% overall. The overall prevalence rates for specific tumor types were 7.5% for nonossifying fibromas, 5.2% for enostoses, 4.5% for osteochondromas, and 1.8% for enchondromas. Nonossifying fibromas demonstrated a bimodal distribution of prevalence, with a peak at 5 years (10.8%) and another after skeletal maturity (13.3%). The median age at the first appearance for all tumors combined was 9 years (range, 2 to 15 years), but varied by tumor type. Nonossifying fibromas often resolved (7 [37%] of 19), with further resolution possible beyond the last available radiograph. Enostoses, osteochondromas, and enchondromas persisted until the last available radiographs in all subjects. CONCLUSIONS: The prevalence of benign childhood bone tumors of the extremities was 18.9% in a historical asymptomatic population. Longitudinal radiographs allowed observation of the timing of the first appearance and the potential for resolution for each tumor type. These findings provide unique evidence to answer many commonly encountered questions when counseling patients and their families on benign bone tumors. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Solitary enchondromas-diagnosis and surveillance : Danish guidelines.

Enchondromas (EC) are frequent incidental findings on magnetic resonance imaging (MRI) performed for the diagnosis of joint pathology, especially observed on MRI examinations of the knee and shoulder. Enchondroma has potential for malignant transformation to chondrosarcoma (CS), and it may be difficult to distinguish EC from low-malignant CS on the basis of imaging or histopathology studies. Therefore, EC is mostly followed up to monitor any growth and/or changes indicating aggressive tumor.There is no consensual evidence on when and how to follow up patients with EC with regard to potential malignant transformation. Therefore, the Danish Multidisciplinary Cancer Groups initiated and supported the elaboration of Danish guidelines in 2020 based on a literature review. The guidelines are presented here, in addition to a summary of the background literature.

The incidence and outcome of chondral tumours as incidental findings on investigation of shoulder pathology.

PURPOSE: The aim of this study is to describe outcomes of incidental chondral tumours in the shoulder referred to our Bone Tumour Unit (BTU). METHODS: Our hospital radiology database was searched using the filtered terms "enchondroma", "low-grade chondral tumour", "chondrosarcoma" with "humerus", "arm", "shoulder", "scapula" and "clavicle". Case note review of results assessed primary reasons for referral, radiological diagnosis, recommended management with subsequent reviews and outcomes, either in clinic or surveillance scan reports. RESULTS: Ninety-nine patients had full case note review, mean age 54.5 years (range 18-84 years). Mean follow-up was 41.7 months (range 1-265 months). Over 50% of patients were referred for shoulder pain. Three patients had high-grade chondrosarcoma. Forty-three patients had interval scans, none showing any changes. Thirty-five patients had surgery for their lesions with one recurrence. Forty-four patients had alternative diagnoses made on clinical and radiological examination. At most recent follow-up, 70% of these patients were asymptomatic after physiotherapy/surgical attention to their alternative diagnoses. CONCLUSIONS: Chondral lesions in the shoulder have low risk of malignant transformation and are rarely responsible for shoulder symptoms. We recommend patients be referred to a dedicated BTU for surveillance if there are any concerning features, but to proceed with management for any alternative diagnosis.

Skull Base Enchondroma and Chondrosarcoma in Ollier Disease and Maffucci Syndrome.

BACKGROUND: Maffucci syndrome (MS) and Ollier disease (OD) are rare diseases characterized by multiple benign enchondromas. The incidence of skull base (SB) enchondromas and the risk of malignant transformation remain unknown. Most SB lesions are asymptomatic, and surgical resection carries significant morbidity. Observation may be a reasonable strategy. We report our experience with observation of probable SB enchondromas in MS/OD patients. METHODS: Retrospective review of OD/MS patients with cranial imaging between 1995 and 2018 at 1 institution. RESULTS: 14 patients were included: 3 with MS (21.4%) and 11 with OD (78.6%). The median age was 28 years (range, 11-74 years) and 57.1% were female. Extracranial chondrosarcoma was reported in 3 (21.4%) patients. Seven (50%) patients with SB enchondroma or chondrosarcoma were identified on initial imaging. In patients with SB lesions, the indications for imaging were headache (n=3), seizure (n=1), and diplopia (n=1); 2 cases were incidental findings. The most commonly involved structures were petroclival fissure (86%) and clivus (71%). Treatment included observation (6/7) and resection (1/7). Follow-up imaging was available for all SB lesions, with a mean interval of 50.7 months (range, 5-225 months) and was negative for progression in all patients. CONCLUSIONS: Primary SB lesions in OD/MS patients frequently present in the petroclival junction. Cranial screening and close observation should be considered in MS/OD patients, given the increased risk of intra-axial intracranial tumors, de novo chondrosarcomas, or malignant degeneration of previously known lesions. In asymptomatic patients, observation appears to be a safe strategy in this cohort. Further case accumulation and follow-up are required to better understand the long-term outcomes.

Intracranial Dural Parafalcine Chondroma: Case Report and Systematic Review of the Literature.

Intracranial chondromas are rare, benign neoplasms representing only 0.2%-0.3% of neoplastic intracranial lesions. They commonly originate from the skull base but can infrequently arise from the falx, convexity dura, or ventricular ependyma. Diagnosis requires histopathologic confirmation, as patients present with nonspecific symptoms related to mass effect, and imaging characteristics often resemble meningiomas, oligodendrogliomas, and vascular malformations. We describe the case of a patient harboring a parafalcine dural chondroma that was discovered incidentally and was managed surgically at our institution. We also provide a systematic review of the literature to elucidate incidence, origin, imaging findings, surgical management approaches, and prognosis of this rare tumor.

Prevalence of cartilaginous tumours as an incidental finding on MRI of the knee.

OBJECTIVES: The purpose was to determine prevalence of enchondromas and atypical cartilaginous tumour/chondrosarcoma grade 1 (ACT/CS1) of the knee on MRI in a large cohort study, namely the Netherlands Epidemiology of Obesity (NEO) study. METHODS: Participants aged 45 to 65 years were prospectively included, oversampling overweight and obese persons. Within a subgroup of participants, MRI of the right knee was performed and screened for incidental cartilaginous tumours, as defined by their characteristic location and appearance. RESULTS: Forty-nine cartilaginous tumours were observed in 44 out of 1285 participants (estimated population prevalence 2.8 %, 95 % CI 2.0-4.0 %). Mean largest tumour diameter was 12 mm (range 2-31 mm). Eight participants with a tumour larger than 20 mm or a tumour with aggressive features were referred to rule out low-grade chondrosarcoma. One was lost to follow-up, three had histologically proven ACT/CS1 and four had dynamic contrast MRI findings consistent with benign enchondroma. CONCLUSIONS: Incidental cartilaginous tumours were relatively common on knee MRI and may be regarded as a normal concurrent finding. However, more tumours than expected were ACT/CS1. Because further examination was performed only when suspicion of chondrosarcoma was high, the actual prevalence might be even higher. KEY POINTS: • Incidental cartilaginous tumours are relatively common on knee MRI. • Most incidental cartilaginous tumours are small and lack suspicious features. • Small cartilaginous tumours without suspicious findings may be a normal concurrent finding. • Large tumours and/or those with suspicious findings should be further investigated. • Atypical cartilaginous tumour/chondrosarcoma grade 1 was found more often than expected.

Distribution and evaluation of bone and soft tissue tumors in the middle Black Sea Region.

OBJECTIVE: The aim of this study was to evaluate the characteristics of bone and soft tissue tumors operated on at the Department of Orthopedics and Traumatology at Ondokuz Mayis University Faculty of Medicine Hospital between January 1987 and January 2012. METHODS: This descriptive study retrospectively evaluated 1,925 patients hospitalized with a preliminary diagnosis of tumor. Patients were analyzed for age, gender, tumor incidence and localization. Three hundred and forty-nine patients found to have non-tumor causes. The 94 patients discharged at their own request or deceased during follow-up were not included in the tumor group. RESULTS: Of the 1,482 (76.9%) patients diagnosed with tumor, 687 (46.4%) were bone tumors, 586 (39.5%) soft tissue tumors and 209 (14.1%) metastatic tumors. The most common benign bone tumor was osteochondroma (118; 25%), followed by enchondroma (68; 14.4%) and giant cell tumor (59; 12.5%), and the most common malignant bone tumor was osteosarcoma (58; 27%), followed by chondrosarcoma (36; 16.7%) and Ewing's sarcoma (33; 15.3%). The most common benign soft tissue tumor was cystic hygroma (96; 22%), followed by lipoma (75; 17.2%) and hemangioma (52; 11.9%), and the most common malignant soft tissue tumors were pleomorphic cell tumor (29; 19.3%) and liposarcoma (29; 19.3%), followed by pleomorphic undifferentiated sarcoma (21; 14%). Seventy (33.5%) of the metastatic tumors were of pulmonary origin, 36 (17.2%) were of breast origin and the primary site of the tumor was not clearly determined in 58 (27.8%) patients. CONCLUSION: The distribution of bone and soft tissue tumors appear to have certain characteristics but can show regional differences. We believe that the establishment of a larger series through the collection of these types of studies from centers in which bone and soft tissue tumor surgery is performed will provide important information on the epidemiological features of bone and soft tissue tumors.

Association between previous meniscal surgery and the incidence of chondral lesions at revision anterior cruciate ligament reconstruction.

BACKGROUND: Knees undergoing revision anterior cruciate ligament (ACL) reconstruction typically have more intra-articular injuries than do knees undergoing primary reconstruction. HYPOTHESIS: Previous partial meniscectomy (PM) is associated with a higher rate of chondral lesions at revision ACL reconstruction, whereas previous meniscal repair (MR) is not associated with a higher rate of chondral lesions at revision ACL reconstruction, compared with knees undergoing revision ACL with no previous meniscal surgery. STUDY DESIGN: Cohort study (Prevalence); Level of evidence, 2. METHODS: Data from a multicenter cohort was reviewed to determine the history of prior meniscal surgery (PM/MR) and the presence of grade II/III/IV chondral lesions at revision ACL reconstruction. The association between previous meniscal surgery and the incidence of chondral lesions was examined. Patient age was included as a covariate to determine if surgery type contributes predictive information independent of patient age. RESULTS: The cohort included 725 ACL revision surgeries. Chondrosis was associated with patient age (P < .0001) and previous meniscal surgery (P < .0001). After adjusting for patient age, knees with previous PM were more likely to have chondrosis than knees with previous MR (P = .003) or no previous meniscal surgery (P < .0001). There was no difference between knees without previous meniscal surgery and knees with previous MR (P = .7). Previous partial meniscectomy was associated with a higher rate of chondrosis in the same compartment compared with knees without previous meniscal surgery (P < .0001) and knees with previous MR (P ≤ .03). CONCLUSION: The status of articular cartilage at the time of revision ACL reconstruction relates to previous meniscal surgery independent of the effect of patient age. Previous partial meniscectomy is associated with a higher incidence of articular cartilage lesions, whereas previous meniscal repair is not. Although this association may reflect underlying differences in the knee at the time of prior surgery, it does suggest that meniscal repair is preferable when possible at the time of ACL reconstruction.

Prevalence of shoulder enchondromas on routine MR imaging.

The objective of this study was to examine the prevalence of incidental shoulder enchondromas on routine magnetic resonance (MR) shoulder imaging. Consecutive routine shoulder MR examinations (N = 477) performed for suspected internal derangement were reviewed for the presence of incidental enchondromas. Incidental enchondromas were detected on 2.1% of routine MR shoulder examinations, the vast majority abutting the physeal plate. This prevalence is important to appreciate, in order to form a meaningful differential diagnosis of pathologic proximal humerus lesions.

When should we biopsy a solitary central cartilaginous tumor of long bones? Literature review and management proposal.

Differentiation between benign and low-grade malignant cartilaginous tumors is a radiological and pathological challenge. Based on a literature review, we propose the following guidelines for the management of a solitary central cartilaginous tumor of long bones distinguishing three situations: 1. The tumor is considered to be aggressive and requires surgery if one of the following criteria is present: cortical destruction, Moth-eaten or permeative osteolysis, spontaneous pathologic fracture, periosteal reaction, edema surrounding the tumor on MR images, and soft tissue mass. Tumor biopsy followed by complete intralesional treatment is indicated. 2. The tumor is classified as active if two of the following active criteria are present: pain related to the tumor, endosteal scalloping superior to two-thirds of the cortical thickness, extent of endosteal scalloping superior to two-thirds of the lesion length, cortical thickening and enlargement of the medullary cavity. Tumor biopsy or excision is indicated. 3. The tumor is classified as possibly active if one of the previous active criteria is present. In such cases, bone scintigraphy and dynamic-enhanced MR imaging should be obtained. Radionuclide uptake superior to the anterior iliac crest at bone scintigraphy and early and exponential enhancement at dynamic-enhanced MR are considered as two additional active criteria. After these two examinations, if only one criterion is still present, the lesion can be regarded as possibly quiescent, and the following monitoring is suggested: first follow-up at three to six months and then once a year. Otherwise, if two or more active criteria are present, biopsy is recommended. 4. The tumor is considered quiescent and does not require surgery if no active or aggressive criterion is present. A radiological follow-up can be proposed.

[Enchondroma of the hand - treatment and long-term outcome]. / Enchondrome des Handskeletts - Therapeutisches Vorgehen und funktionelle Langzeitergebnisse.

BACKGROUND: An enchondroma is with up to 90% the most common benign tumour of the hand. Functional long-term outcome studies of the several treatments do not exist. The aim of this study is thus to evaluate the information from our 147 patients about diagnostics, operative treatment and follow-up treatment. METHODS: 147 patients with 183 histologically secured enchondromas of the hand, who had been treated between 1973 and 2004, were analysed by follow-up examination and radiological findings retrospectively. RESULTS: We found 136 mono- and 11 polyostotic lesions. The proximal phalanx was afflicted most commonly (44.8%). There was no preference for one special finger, only the thumb was afflicted below average (9.8%). The most common symptoms were pain and swelling (51.7%) or pathological fracture (25%). We found 11 relapses (7.5%) after an average of 4.4 years. In two cases we found a grade 1 chondrosarcoma. 84.2% of the patients achieved a "very good" or a "good" functional long-term outcome, 11.7% a "fair" and 4.2% a "poor" outcome. CONCLUSION: Standard treatment should be the accurate extirpation of the tumour and subsequent filling of the defect with cancellous bone. Only very small, asymptomatic lesions can be treated conservatively with six-month check-up examinations.

Epidemiology of bone tumors in Mexico City: retrospective clinicopathologic study of 566 patients at a referral institution.

A retrospective analysis of all bone tumors accessioned at a large referral center (Instituto Nacional de Rehabilitacion) in Mexico City between 2000 and 2005 is presented. A total of 6216 biopsies and surgical resection specimens were reviewed during this period, of which 566 corresponded to bone tumors. Benign bone tumors accounted for 71.6% of cases and malignant bone tumors for 28.4%. The tumors affected men in 53.7% of cases and women in 46.3% of cases, with an average age at presentation of 25 years. The femur was the most common location of the tumors (39.9%), followed by the tibia (17.7%) and humerus (11.8%). The commonest malignant bone tumors were osteosarcoma (46.6%) and chondrosarcoma (8.7%). Of malignant bone tumors, 18.6% corresponded to metastases of carcinomas from internal organs and 8.1% were multiple myeloma. The most common benign bone tumor was osteochondroma (43.7%) followed by giant cell tumor of bone (14.6%) and enchondroma (10.1%). The age distribution showed a peak in children and adolescents comprised predominantly of benign lesions and a second peak in young adults that corresponded to malignant bone tumors (principally osteosarcoma). Malignant bone tumors most often involved the femur, vertebra, and tibia. Our results parallel the findings previously reported in the world literature and show a similar distribution and epidemiology as in other developed and underdeveloped countries. Geographic location does not appear to represent a risk factor for any particular type of bone tumor and does not affect the age distribution, location, or histopathologic type of the lesions.

Assessment of interobserver variability and histologic parameters to improve reliability in classification and grading of central cartilaginous tumors.

The distinction between benign and malignant cartilaginous tumors of bone is one of the most difficult subjects in surgical pathology. The grading of chondrosarcoma also seems to vary considerably among pathologists. However, clinical management differs. The purpose of this study was (1) to investigate interobserver variability in histological diagnosis and grading of central cartilaginous tumors and (2) to assess the diagnostic value of defined histologic parameters in differentiating enchondroma and central grade I chondrosarcoma. The interobserver variability was assessed using a set of 16 cases evaluated by 18 specialized pathologists. Subsequently, 20 enchondromas and 37 central grade I chondrosarcomas diagnosed in a multidisciplinary team with full clinical, radiologic, and pathologic data available with 10 years of follow-up were collected. Cytologic and tissue-architectural features were assessed to find an optimal set of parameters to differentiate enchondroma from central grade I chondrosarcoma. We demonstrate considerable variation in the histologic assessment of cartilaginous tumors (weighted kappa=0.78). The distinction between enchondroma and grade I chondrosarcoma was shown to be the most disconcordant (kappa coefficient=0.54), and also the differentiation between grade I and grade II chondrosarcoma was subjected to variation (kappa coefficient=0.80). The application of a combination of 5 parameters (high cellularity, presence of host bone entrapment, open chromatin, mucoid matrix quality, and age above 45 y) allowed optimal differentiation between enchondromas and central grade I chondrosarcomas. With a classification tree based on 2 parameters (mucoid matrix degeneration more than 20% and/or host bone entrapment present), 54 of the 57 (94.7%) cases were assessed correctly (sensitivity 95% and specificity 95%). Our study confirms the low reliability of the diagnosis and grading of central chondrosarcoma. However, these classifications guide therapeutic decision making in daily practice. Therefore, we propose a classification model that, combined with a tailored radiologic assessment, may improve reliability of the diagnosis of cartilaginous tumors.

Incidental enchondromas of the knee.

OBJECTIVE: The purpose of our study was to determine the prevalence of incidental enchondromas on routine MR knee imaging. MATERIALS AND METHODS: We retrospectively reviewed 449 consecutive routine knee MR examinations for the presence of enchondromas. MRI was considered positive when a focal geographic area of lobular marrow replacement (nonsubchondral) was identified on T1 weighting and high signal intensity was seen on T2 weighting. Patients with enchondromas were further evaluated for demographics; lesion site, size, and relationship to the physeal plate; aggressive imaging features described with chondrosarcoma; concurrent internal derangement; and study indication. RESULTS: The prevalence of incidental enchondromas was 2.9% on routine knee MR examinations. The prevalence was highest in the distal femur (2.0%), followed by the proximal tibia (0.7%) and the proximal fibula (0.2%). The average lesion size was 1.9 x 1.2 x 1.3 cm (57% of lesions were < 1 cm). Most lesions were located in the metaphysis (71%) or diaphysis (21%). Enchondromas were within 1.5 cm of the physeal plate in 72% of cases. No aggressive imaging features to suggest chondrosarcoma were seen. All patients had evidence of internal derangement as the cause of symptoms and the request for imaging. CONCLUSION: Incidental enchondromas can be identified on 2.9% of routine MR knee examinations, most frequently in the distal femur (2.0%). This significant prevalence is much higher than in an autopsy series (0.2%), likely reflecting the increased sensitivity of MRI for detecting small lesions, and is important to recognize to avoid confusion with other pathologic entities.

First occurrence of periosteal chondroma (juxtacortical chondroma) in Uromastyxmaliensis (Reptilia: Sauria: Agamidae).

The occurrence of a periosteal chondroma (juxtacortical chondroma) in an adult male Uromastyx maliensis is documented for the first time. The chondroma developed near the right shoulder joint from the periosteal membrane, causing partial atrophy in the surrounding skeletal muscles. In the chondroma tissues widespread central necrosis and secondary calcium salt deposition were observed. Monomorphic chondrocytes were irregularly spread in the chondromucin matrix. The lizard had locomotor problems due to irritation of the periosteum and reduced movement of the bones constituting the shoulder joint caused by the chondroma.

[The results of curettage and bone cementing for enchondromas of the distal femur]. / Femur alt uç enkondromlarinin küretaj ve kemik çimentosu ile tedavi sonuçlari.

OBJECTIVES: We evaluated patients who were treated with curettage and cementing for enchondromas localized in the distal femur. METHODS: The study included 13 patients (7 females, 6 males; mean age 54 years; range 43 to 65 years) who underwent surgery for enchondromatosis in the distal femur. Enchondromas were detected incidentally in 10 patients; of these, complaints of pain appeared afterwards in seven patients. Surgery involved curettage and cement filling of the defects. Preoperative biopsies were obtained in seven patients. Clinical evaluations were made with a visual analog scale. The mean follow-up period was four years (range 1 to 5 years). RESULTS: Radiographically, the size of the lesions ranged from 3 cm to 6 cm (mean 4.5 cm). Computed tomography showed cortical extension in five patients and erosion leading to narrowing in the posterior cortex in one patient. The mean pain score decreased from 3.63 (range 0 to 7) to 0.54 (range 0 to 3) postoperatively (p<0.05). Histopathological diagnoses of surgical specimens were enchondroma in 12 patients and grade 1 chondrosarcoma in one patient. Postoperatively, only one patient who had erosion and narrowing in the posterior cortex required cast immobilization for three weeks. None of the patients had recurrence, sarcomatous changes, or infection. No functional loss developed after surgical treatment. CONCLUSION: Treatment of femoral enchondromas with curettage and cementing yields successful functional and radiologic results.

Solitary epiphyseal enchondromas.

BACKGROUND: Enchondromas originating in the epiphyses of long bones are rare. The purpose of the present study was to evaluate the prevalence as well as the radiographic and clinical characteristics of epiphyseal enchondromas among patients who had been referred to the Armed Forces Institute of Pathology and Walter Reed Army Medical Center. METHODS: We performed a retrospective review of 761 patients who had been referred to our two institutions over an approximately fifty-five-year period and who received a final diagnosis of enchondroma. All lesions had been biopsied, and the pathological diagnosis had been confirmed. Lesions of the hands, feet, or axial skeleton (253 patients) as well as lesions that appeared to originate in the metaphysis or diaphysis (475 patients) were excluded. Only enchondromas of the long bones that originated in the epiphysis were analyzed. The study group included thirty-three patients (twenty male patients and thirteen female patients) with a mean age of 26.7 years, including eleven patients with open physes. We performed additional descriptive analyses with regard to patient age, gender, lesion location, clinical presentation, and treatment as well as an extensive radiographic analysis. RESULTS: The most common locations were the proximal part of the humerus (ten lesions; 30%) and the distal part of the femur (six lesions; 18%). The most common presenting symptom was pain (twenty-three patients). Radiographic analysis demonstrated extensive matrix mineralization in association with twenty-three lesions. Twenty-eight of the thirty-three lesions were geographically well defined; of these, twenty-one had sclerotic borders, and seven did not. Although all lesions were centered and were predominantly located within the epiphysis, twenty of the thirty-three lesions demonstrated radiographic evidence of metaphyseal extension, including four of the eleven lesions in patients with open physes. Twenty-four lesions extended into the subchondral bone. The mean size of the thirty-three enchondromas in greatest radiographic dimension was 2.7 cm (range, 1.1 to 4.9 cm). Twenty-six of the thirty-three lesions were amenable to surgical treatment with curettage with or without bone-grafting, with only one recurrence. With the limited follow-up available, no lesion underwent sarcomatous degeneration. CONCLUSIONS: Epiphyseal enchondromas are rare lesions. Although their biologic behavior appears to mirror that of conventional metaphyseal enchondromas, their proximity to the joint space may lead to more frequent painful symptoms, a propensity for physeal involvement, and the need for earlier definitive surgical intervention.

The causes of pain in benign solitary enchondromas of the proximal humerus.

Patients with benign solitary enchondromas of the proximal humerus frequently present to the diagnosing physician with shoulder pain. Once the lesion is considered benign, emphasis can be placed on identifying the etiology for the pain. We reviewed our experience with these patients to identify the cause of the presenting pain. A retrospective review of clinical records and radiographic studies (radiographs, magnetic resonance images, and bone scans) was done for all patients presenting to an orthopaedic oncology unit with solitary enchondroma of the proximal humerus. Attention was focused on diagnostic evidence of additional disease in the shoulder. Fifty-seven patients (mean age, 53.6 years) met the criteria of the study and were included for evaluation. Of patients presenting with pain, 82% (47 of 57 patients) had findings seen on magnetic resonance imaging scans that correlated with the initial clinical diagnostic impression, suggesting that other disease was present that could explain the pain. Solitary enchondromas of the proximal humerus often are found incidentally during the initial evaluation of patients with shoulder pain. This study showed that additional treatable disease usually is present in patients with enchondromas of the proximal humerus.