Evaluation of different treatment modalities for fractured and non-fractured simple bone cyst: A single-center review of 68 patients

Simple bone cysts (SBCs) occur most frequently in the proximal aspect of the humerus and femur in growing age and are associated with intercurrent pathological fractures in up to 87%. Therapeutic management of SBCs remains controversial. The aim of this study was to examine the outcome of conservative and various surgical treatment modalities considering the specific anatomic location and integrity of the SBC.In this retrospective study, we analyzed 68 cases of SBCs who underwent a conservative or surgical treatment between 2009 and 2020 with a mean follow-up of 30.1 months. The epidemiological characteristics, complications, clinical, and radiographic outcome after conservative or surgical treatment were assessed.The study includes 50 male (73.5%) and 18 female (26.5%) patients with a mean age of 9.1 years. The most common locations were the proximal humerus (69.2%, n = 47) and femur (16.2%, n = 11). In 43 cases (63.2%; upper limb n = 40, lower limb n = 3) a pathological fracture occurred. Fifty patients (73.5%; upper limb n = 40, lower limb n = 10) underwent a conservative treatment. In 11 cases (16.2.1%; upper limb n = 4, lower limb n = 7) an intralesional curettage and defect reconstruction with bone substitute without stabilization were performed. Five patients (7.3%; upper limb n = 4, lower limb n = 1) received an osteosynthesis, in two cases (2.9%; upper limb 1; lower limb 1) combined with an intralesional curettage and defect reconstruction with bone substitute. All 32 pathological fractures treated conservatively (upper limb n = 31, lower limb n = 1) healed within 6 weeks; 17/43 patients (39.5%) suffered at least one second fracture. After intralesional curettage and defect reconstruction with bone substitute local recurrence was observed in 5/13 cases (38.5%). Spontaneous consolidation, at least partially, was observed in three cases (4.4%) following conservative treatment after fracture. No relevant secondary angular or torsional deformity was observed after treatment.The majority of SBCs can be treated conservatively, especially in the upper extremity. However, if a fracture is completely dislocated, joint affecting, unstable or open, surgical treatment is necessary. Load-dependent pain or the inability to mobilize timely after fracture can necessitate surgical treatment in SBCs affecting the lower extremity. Spontaneous resolution, especially after fracture, can be seen in rare cases.

Solitary Bone Cyst Like Areas in Myositis Ossificans: A Breast Mass in a Child

Myositis ossificans is an extraosseous, benign tumor-like condition characterized by prominent heterotopic ossification. Cystic degeneration in myositis ossificans is an uncommon entity. Case report: A 13-year-old girl presented with a large and painful breast lump. Physical examination revealed a mobile, hard mass, clinically resembling a fibroadenoma. The mass was excised and diagnosed as myositis ossificans with central bone cyst like changes. Conclusion: Our case represents the first myositis ossificans case with central bone cyst like changes in a child.

Identification of EWSR1-NFATC2 fusion in simple bone cysts

AIMS

Simple bone cysts are benign intramedullary tumours primarily involving the long bones in skeletally immature individuals. Several mechanisms have been proposed for their pathogenesis. Although the diagnosis is typically straightforward, the interpretation can be problematic, because of superimposed fracture causing them to resemble aneurysmal bone cysts and other tumours. EWSR1-NFATC2 or FUS-NFATC2 fusions, which are characteristic of a subset of aggressive round cell sarcomas, have been recently detected in simple bone cysts. The aim of this study was to examine the clinicopathological and molecular features in a series of simple bone cysts.

METHODS AND RESULTS

Using RNA-based next-generation sequencing and/or fluorescence in-situ hybridisation, we investigated the presence of EWSR1 or FUS rearrangements in nine simple bone cysts. The patients were five females and four males, aged 3-23 years (median, 14 years); the tumours ranged from 19 mm to 160 mm (median, 46 mm) in size, and involved the femur (n = 3), humerus (n = 2), fibula (n = 2), tibia (n = 1), and iliac wing (n =1). We identified three cases with EWSR1-NFATC2 fusion (showing identical breakpoints to those in EWSR1-NFATC2 sarcomas) and one additional case with FUS rearrangement. Unlike in EWSR1-NFATC2 sarcomas, immunohistochemical expression of NKX3.1 and NKX2.2 was absent in two simple bone cysts tested.

CONCLUSIONS

More than 40% of simple bone cysts harbour genetic alterations confirming that they are neoplastic, investigation of EWSR1 and/or FUS rearrangement may help to distinguish simple bone cysts from mimics, and NFATC2 rearrangement is not pathognomonic of malignancy.

Solitary Bone Cyst of Posterior Maxilla: A Rare Presentation

Solitary bone cyst (SBC) is an uncommon, nonneoplastic osseous lesion that mainly affects metaphysis of long bones and rarely presents in jaws. Due to the lack of true epithelial lining, it is considered as a pseudocyst. It is generally asymptomatic and often discovered incidentally during routine radiographic examination as well-defined unilocular or multilocular radiolucent lesion in the posterior mandible mainly in the first two decades of life. Here, we report a very rare case of a 15-year-old female patient having a lesion in the posterior maxilla with clinical, radiological, and histopathological presentations of SBC.

Unicameral bone cyst in the pelvis: report of a case treated by placement of screws made from a composite of unsintered hydroxyapatite particles and poly-l-lactide

Unicameral bone cysts are fluid-filled benign lesions that occur mostly in the long bones. Unicameral bone cysts in the pelvis are extremely rare. Continuous decompression using titanium or hydroxyapatite screws has been reported as a treatment. Screws made from a composite of unsintered hydroxyapatite particles and poly-l-lactide can be used for the treatment. An adolescent male patient presented with a unicameral bone cyst in the ilium extending to a region adjacent to the hip joint. As initial treatment, the cortex was fenestrated when the patient was 13 years old and β-tricalcium phosphate implanted. The cyst first reoccurred when the patient was 15 years old and again when he was 17 years old. During the most recent treatment, unsintered hydroxyapatite particles and poly-l-lactide composite screws were placed, and no recurrence was observed during 2 years of follow-up. The slow biodegradability and absorbability of the screws may allow continuous drainage of unicameral bone cysts.

Radiological Evaluation Key to Diagnosis of Idiopathic Solitary Cyst

Idiopathic solitary cysts have a predilection for long bones and the mandible. Although the origin of these cysts is unclear, the prognosis seems to be good, given proper diagnosis and surgical treatment. A 14-year-old female patient with a bone lesion in the right mandibular ramus was referred to the Department of Pediatric Dentistry at the Medical University of Gdansk, Poland. Due to severe headache lasting two days, the patient had previously undergone magnetic resonance imaging (MRI) examination of the head. A unilocular bone cyst in the mandible was discovered incidentally. Comparison with a previous orthopantomogram (OPG) taken two years earlier for routine dental treatment revealed a clearly visible but smaller bone lesion at the same location. Surgery was carried out in order to achieve bone regeneration. This report documents the importance of careful evaluation and assessment of all radiographs taken, as the lesion could have been diagnosed and treated much earlier, thus lowering the risk of complications.

A rare presentation of a simple bone cyst

Simple bone cyst is an oft-described entity, which goes by many sobriquets and has been presented in the literature as early as 1926. It is a lesion of unclear etiology with many proposed hypothesis for its pathogenesis and nonspecific histopathological presentation. We present a case of a solitary bone cyst, which clinically presented as a solitary lesion, but radiological examination revealed multiple lesions peppering the maxilla and the mandible, thereby highlighting the importance of atypical presentation and “surprise” lesions that may show up on radiological examination.

Etiological aspects of solitary bone cysts: comments regarding the presence of the disease in two brothers. Is the genetic theory sustainable or is it pure coincidence? - Case report

Beginning the study of benign tumors of the bone in children and adolescents, a group of diseases that have in common the clinical aspects, evolution, and surgical treatment, genetic theory in the etiology of the solitary bone cyst, can be sustained by some cases of siblings with the same disease. This paper presents the particular case of two brothers, treated in our clinic for the same condition: solitary bone cyst of the proximal humerus. The two brothers were admitted with the same symptoms, the localization was the same. Because of the genetic studies regarding this condition, we think that it is an interesting aspect of this pathology. This study also tried to find the most appropriate approach in the treatment of these tumors.

Pathological fractures of the proximal femur due to solitary bone cyst: classification, methods of treatment

Fractures are a very important issue in a child's orthopedic pathology. Neglected a good amount of time, being considered "not too serious", or "rare", having better and faster healing methods and not leaving sequels, like in the case of adults, a child's fractures remain an important chapter of traumatology in general. Because of the raising prevalence of child osteoarticular traumas, as well as new less invasive treatment methods, this theme is always to date. The paper analyzes particular cases of bone fractures that appeared due to minor traumas, on bones with a high brittleness, localized especially on the long bones. Although these fractures on a pathological bone can be seen at all levels of the human skeleton, this paper focuses on fractures located in the proximal third part of the femur. A group of children admitted in the Pediatric Orthopedic Department of "M.S. Curie" Hospital-Bucharest with this diagnostic, were analyzed between 2009 and 2013.

Unicameral Bone Cyst in the Calcaneus of Mirror Image Twins

Unicameral bone cysts (UBCs) are benign tumor-like lesions that commonly occur in the diaphyseal or metaphyseal region of the long bones within the first 2 decades of life. Until today, the pathogenesis of UBC has been unclear, but mechanisms such as vascular occlusion or a response to trauma have been supposed. During the past decade, in particular, the genetic aspects of the development of this rare lesion have been discussed. We present the first case of mirror image monozygotic twins with a mirror image UBC of the calcaneus. Our findings reinforce the importance of additional studies to understand the significance of cytogenetic factors in the etiology of UBC.

A comparative study of clinicopathological features between simple bone cysts of the calcaneus and the long bone

BACKGROUND

The potential unrevealed clinicopathological differences between simple bone cysts situated in the calcaneus (calcaneal bone cysts) and those situated in long bones (long bone cysts) were investigated in the present study.

METHODS

A total of 41 cysts from 41 patients who underwent operative treatment were evaluated: 16 cysts in the calcaneus, 17 in the humerus, 7 in the femur, and 1 in the tibia. The clinical course, radiological findings, and histological features were retrospectively reviewed.

RESULTS

The mean patient age was 11.5 years (range, 3 to 25 years), and the mean follow-up was 33.0 months (range, 12 to 77 months). The mean patient age was significantly higher in patients with calcaneal bone cysts (13.5 years; long bone cysts, 10.2 years, P < .05). No treatment failure was seen for patients with calcaneal bone cysts, while 7 long bone cysts required reoperation. In H&E-stained specimens of the cyst wall, cholesterol clefts were identified in 10 of the 16 calcaneal bone cysts (62.5%), whereas none were identified in long bone cysts (0%; P < .0001).

CONCLUSION

Our study elucidates the different clinicopathological features existing between calcaneal bone cysts and long bone cysts. Cholesterol clefting is most likely due to hemorrhaging and the subsequent breakdown of blood in the cyst. The significance of these differences between long bone and calcaneal cysts is still open to conjecture.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.