Enchondroma in the Diaphysis of Tibia – A Case Report and Review of its Characteristics and Differentials in the Diaphysis

Introduction: Enchondroma is a solitary, benign, intramedullary cartilaginous tumor commonly noticed in the phalanges of hands and feet with characteristic radiological features. Its occurrence in aberrant sites with atypical features lead to diagnostic dilemma. Enchondromas which are usually managed non-operatively can mimic other benign and malignant lesions, especially chondrosarcoma. Case Report: We report the case of a 31-year-old farmer who presented with long standing inconspicuous pain in his left leg which turned out to be a diaphyseal enchondroma even though it demonstrated aggressive radiological features mimicking a chondrosarcoma. Incisional biopsy was done from the scalloped areas to obtain the correct histological diagnosis. He underwent thorough curettage of the lesion and remains asymptomatic 2 years after the procedure. We attempt to discuss the differentials which the orthopedic surgeon should keep in mind for diaphyseal lesions mimicking enchondroma. Conclusion: Though classically found in metaphysis, Enchondromas are not uncommon in diaphysis of long bones. Enchondromas are generally benign, but can cause diagnostic dilemma when they present with aggressive features at rare locations and surgeons should be wary of the differentials. Despite a size of more than 6 cm and evidence of cortical erosion and intramedullary widening, the lesion could still be benign. Early biopsy will help to differentiate Enchondroma from a malignant transformation or malignant tumor. Keywords: Enchondroma, chondrosarcoma, diaphysis, multilocular, endosteal scalloping, chondroma.

Bilateral Facial Paralysis and Deafness in a Child Treated for Acute Lymphoblastic Leukemia

Involvement of the ear and temporal bone in acute leukemias are uncommon. We report a case of atypical mastoiditis with bilateral facial paralysis in a child diagnosed with Acute Lymphoblastic Leukemia (ALL). A 20-month-old male child was diagnosed with ALL and developed otorrhea unresponsive to antimicrobial treatment during the first week of chemotherapy followed by hearing loss, loss of balance, and bilateral facial paralysis. A CT scan of the mastoids showed cortical erosion of the temporal bone and presence of soft tissue contents filling the mastoid cells and external auditory canal bilaterally. Mastoidectomy was performed to collect material for analysis. Histopathologic examination of the material revealed an active chronic inflammatory process, with a moderate amount of plasma cells. Chemotherapy was reintroduced 3 weeks after the surgical procedure, and progressive improvement of otorrhea and imbalance was noted. Grade III House–Brackmann peripheral facial paralysis persisted on 6-month follow-up, and the patient is in rehabilitation program.

Risk Indicators for Osteomyelitis versus Osteitis on MRI

Category: Other Introduction/Purpose: Magnetic resonance imaging (MRI) is the most accurate modality for identifying osteomyelitis with prior literature reporting sensitivities and specificities of 90% and 80%, respectively. MRI findings consistent with osteomyelitis include bone marrow edema, hyperintensity on T2-weighted images (T2WI), and confluent signal on T1-weighted images (T1WI). Additional radiographic indicators include superficial ulceration, exposed bone, and cortical erosion. What is unclear is which of these factors, alone or in combination, is most closely associated with a diagnosis of osteomyelitis. The goal of the current study is to determine which clinical risk factors and MRI findings are most predictive of osteomyelitis. Methods: After IRB approval, clinical records of one hundred five patients who underwent bone biopsy of the foot or ankle between 2015-2017 were retrospectively examined. Patients who did not obtain MRI within 30 days preceding bone biopsy were excluded. A total of 65 patients were included. Diagnosis of osteomyelitis was determined by histology. Blinded radiologic review of MRI was performed to evaluate presence of 4 key indicators of osteomyelitis: hyperintensity on T2WI, confluent signal on T1WI, depth of ulceration, and presence of cortical erosion. Bivariate Poisson regression with robust error variance was used to determine if an association existed between the incidence of osteomyelitis and patient comorbidities and radiographic indicators. A multivariate Poisson regression including patient and radiographic indicators as controls was performed using backwards, stepwise regression until only variables with p<0.05 remained. Results: Of 65 subjects, 41 (63.1%) and 24 (36.9%) had pathologic evidence of osteomyelitis or indeterminate results, respectively. The sensitivity (Se) and specificity (Sp) for osteomyelitis versus osteitis by radiologist heuristic was 51.4% and 77.8%, respectively. The sensitivity and specificity for hyperintensity on T2WI (Se:90.2%; Sp:16.7%), confluent signal on T1WI (Se:43.9%; Sp:83.3%), depth of ulceration (Se:78.0%; Sp:41.7%), and cortical erosion (Se:41.5%; Sp:79.2%) are detailed. Bivariate analysis determined diabetes (Relative risk [RR]=3.2, 95% Confidence Interval [CI]=1.14-8.72, p=0.026) and confluent signal on T1WI (RR=1.5, 95%CI=1.08-2.16, p=0.015) were risk factors for osteomyelitis. An immunocompromised state and presence of cortical erosion were trending towards statistical significance. Multivariate analysis determined an immunocompromised state (RR=1.8, 95%CI=1.32-2.39, p=<0.001) and confluent signal on T1WI (RR=1.6, 95%CI=1.08-2.28, p=0.019) to be independent risk factors for osteomyelitis. Conclusion: The results of this study demonstrate that confluence of signal on T1WI and an immunocompromised state were independent risk factors for osteomyelitis. Additionally, patients with evidence of cortical erosion or diabetes should be more thoroughly evaluated if clinical concern for osteomyelitis is high. Patients with these comorbidities or radiographic indicators should undergo bone biopsy for definitive diagnosis.

Malignant Transformation of Synovial Chondromatosis: A Systematic Review

Background: Synovial chondromatosis (SCh) can undergo malignant transformation. Pathologic diagnosis of secondary synovial chondrosarcoma (SChS) is challenging and misdiagnosis may result in over- or undertreatment. Method: A systematic review revealed 48 cases of SChS published in 27 reports since 1957. Data was collected to identify findings indicative of SChS and outcomes of treatment. Results: At median follow-up of 18 months, patients were reported as alive (10%), alive without disease (22%), alive with disease (15%), dead of disease (19%), dead of pulmonary embolism (4%), and unknown (29%). Initial diagnosis of SChS (grade: low/unknown 48%, intermediate/high 52%) was after biopsy in 58%, local resection in 29%, and amputation in 13%. Seventy-four percent of patients underwent 1.8 (mean) resections. Patients treated prior to 1992 were managed with amputation in 79% of cases compared to 48% after 1992. Symptoms were present for 72 mos prior to diagnosis of SChS. Synovial chondrosarcoma demonstrated symptom progression over several months (82%), rapid recurrence after complete resection (30%), and medullary canal invasion (43%). The SChS tumor dimensions were seldom quantified. Conclusion: Malignant degeneration of synovial chondromatosis is rare but can necessitate morbid surgery or result in death. Pathognomonic signs for SChS including intramedullary infiltration are present in the minority of cases. Progression of symptoms, quick local recurrence, and muscle infiltration are more suggestive of SChS. Periarticular cortical erosion, extra-capsular extension, and metaplastic chondroid features are non-specific. Although poorly documented for SChS, tumor size is a strong indicator of malignancy. Biopsy and partial resection are prone to diagnostic error. Surgical decisions are frequently based on size and clinical appearance and may be in conflict with pathologic diagnosis.

Whole-spine Computed Tomography Findings in SAPHO Syndrome

Objective.We evaluated the whole-spine computed tomography (CT) findings in patients with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome to improve our understanding of this rare disease.Methods.Whole-spine CT images obtained in 69 patients with SAPHO were reviewed. For each individual, a total of 25 vertebrae were evaluated for the distribution of affected vertebrae, CT manifestations of vertebral lesions, symmetry and location of distribution of the lesions on vertebrae, involvement pattern, and narrowing of adjacent intervertebral disc space. Paravertebral ligamentous ossifications, apophyseal joint disorders, and costovertebral joint disorders were also evaluated.Results.All the 69 patients with SAPHO exhibited abnormalities on whole-spine CT. Sixty-four had vertebral lesions, 52 had paravertebral ossifications, and 47 had both. The vertebral lesions were observed in 441 vertebrae, with a predilection for thoracic spine. The lesions exhibited a mixture of cortical erosion, reactive osteosclerosis of surrounding cancellous bone, and syndesmophyte. They may be confined to the vertebral corner (65.1%) or be extensive, involving the endplate (34.9%). Corner lesions could start in any part of the epiphyseal ring. The lesions were asymmetrically distributed. The affected vertebrae were more consecutively involved in a “kissing” appearance (78.2%). Intervertebral disc spaces were usually normal or mildly narrowed. There were 320 foci of paravertebral ossifications observed, with a predilection for the supraspinous ligament. Paravertebral ossifications were delicate and segmental. Ossifications throughout annulus fibrosis and apophyseal joint were not observed.Conclusion.Our investigation of the distributional, morphological features and the involvement pattern of spinal lesions in patients with SAPHO demonstrated distinct CT characteristics.

Adult Intramedullary Ewing Sarcoma of the Proximal Hip

Ewing sarcoma of bone is classically a permeative lesion in the diaphysis of long bones in children. While they occur primarily in children and adolescents, they can be seen in young adults in their 20s, but these are typically seen in flat bones. The permeative nature of the lesion can elicit new bone formation creating a partially sclerotic appearance, cortical expansion presenting as a “Codman triangle,” or have an “onion-skin” type of aggressive periosteal reaction/periostitis. Ewing sarcoma is rarely seen without an associated soft-tissue mass and is even rarer to just have benign-appearing periostitis (e.g., thick, uniform, or wavy cortex). We present such a case of Ewing sarcoma in a young adult confined to just the medullary metadiaphysis without cortical erosion or soft-tissue mass. To the best of our knowledge, this is the first case to be reported in the radiology literature.

Hydatid Disease of the Femur with an Extraosseous Extent due to a Former Biopsy Complicated by a Pathological Fracture

Hydatid disease of the bone represents about 1–2.5% of all human hydatid disease. Spine is the most affected part of the skeleton with 50% incidence of all bone hydatidosis. Extraspinal bone hydatidosis is much rare. Diagnosis is difficult in the bone hydatid disease. Bone tumors, tumor-like lesions, and specific and nonspecific infections should be considered in the differential diagnosis. Radiological, laboratory, and clinical findings combined with strong element of suspicion are the key for diagnosis. Bone biopsies should be avoided because of the danger of anaphylaxis, sensitization, and spread. This paper describes the management of a patient with primary hydatidosis of the femur, which had been complicated by an extraosseous involvement, cortical erosion, and a pathological fracture due to a former needle biopsy.