Management of a solitary bone cyst using a custom-made surgical guide for a minimally invasive approach: technical note and case report.

BACKGROUND: Solitary Bone Cyst (SBC), also known as a simple bone cyst, hemorrhagic cyst, or traumatic cyst is classified by the WHO among non-odontogenic benign lesions of the jaw. The article explores the use of a static 3D-printed surgical guide to treat mandibular SBC, emphasizing a minimally surgical approach for this lesion. CASE PRESENTATION: A 20-year-old woman was referred for a persistent mandibular SBC lacuna, without specific complaints. Her medical history included a previous bone trepanation for a SBC in the same area, radiologically and surgically confirmed. X-ray assessment showed a well-defined unilocular radiolucency surrounding the root of the first left lower molar (tooth #36), measuring 10 × 10 mm. Pulp sensitivity was normal. CBCT data and STL files of dental cast were obtained preoperatively and registered. A 3D-printed surgical guide was used for minimally invasive trepanation of the buccal cortical. The simulation used a targeted endodontic microsurgery approach in order to determine axis and diameter of the trephine. Surgery was performed under local anesthesia. The guide was tooth supported integrating tubes and a fork for guiding precise trepanation. A 3.5 mm round bone window was created, leaving an empty cavity confirming SBC diagnosis and permitting bone curettage. A blood clot was obtained to promote bone healing. Complete reossification was observed after 6 months. The follow-up at 2 years confirmed a complete bone healing with normal pulp sensitivity. DISCUSSION: The 3D-printed windowed surgical guide with dental support offers big advantages, including improved visibility and reduced errors. Compared to traditional guides, it eliminates visual hindrance and allows easier and quick access to confined areas as well as an improved irrigation during drilling process. The article also highlights the importance of preoperative planning while acknowledging potential limitations and errors and surgical complications. CONCLUSION: The use of the 3D-printed surgical guide could be used in routine for minimally invasive intervention of SBC. This case also demonstrates the potential utility of this approach in various procedures in oral and maxillofacial surgery. The technique provides precise localization, reducing complications and enhances operative efficiency.

Quiste óseo simple de resolución espontánea: reporte de caso y revisión de la literatura / Simple bone cyst of spontaneous resolution: case report and literature review

Introducción: El quiste óseo simple (QOS) es un pseudoquiste intraóseo, de etiología desconocida que representa el 1% de los quistes maxilares. Radiográficamente se observa una imagen radiolúcida de bordes bien definidos, irregulares o festoneados. Su tratamiento consiste en la exploración quirúrgica y curetaje de paredes óseas. En pocas ocasiones se ha descrito resolución espontánea. El propósito de este documento es presentar un caso de QOS de resolución espontánea y realizar una revisión de literatura.Reporte de caso:Mujer de 12 años consulta para evaluación odontológica de rutina. En radiografía panorámica se observa lesión radiolúcida entre raíces de dientes 4.4 y 4.5, de límites bien definidos corticalizados. Se complementó con tomografía computarizada de haz cónico, donde se observó adelgazamiento de tablas óseas. Se realizó un diagnóstico presuntivo de QOS. Se controló a los 3 y 3,5 años observándose hueso de leve mayor densidad que el hueso circundante.Materiales y métodos:Se realizó una revisión de literatura sobre QOS de resolución espontánea en PubMed, Scopus y Web of Science, relacionando los términos libres “simple bone cyst” “spontaneous resolution” “jaws” y sus variantes.Resultados:Se encontraron 13 casos de QOS de resolución espontánea. Las características clínicas y radiográficas de los casos coinciden con la literatura. El 54% de los casos tuvo resolución espontánea en un periodo menor o igual a 5 años.Conclusión:En el presente caso se realizó el seguimiento radiográfico del paciente, demostrando que controlar en el tiempo puede considerarse como tratamiento, ya que la lesión podría resolverse espontáneamente.(AU)

Introduction: Simple bone cyst (SBC) is an intraosseous pseudocyst, of unknown etiology, which represents 1% of maxillary cysts. Radiographically, a radiolucent image with well-defined, irregular or scalloped edges is observed. Treatment consists of surgical exploration and curettage of bone walls. Spontaneous resolution has rarely been described. The purpose of this paper is to present a case of spontaneous resolution of SBC and perform a literature review.Case Report:A 12-year-old woman attends to a routine dental evaluation. Panoramic radiography shows a radiolucent image between roots of teeth 4.4 and 4.5, of well-defined corticated borders. It was complemented with cone-beam computed tomography examination, where thinning of cortical bone was observed. A presumptive diagnosis of SBC was performed. Controls at 3 and 3,5 years were performed and bone of slightly higher density than the surrounding bone was observed.Materials and methods:A literature review on SBC of spontaneous resolution was performed in PubMed, Scopus and Web of Science, relating the free terms “simple bone cyst” “spontaneous resolution” “jaws” and their variants.Results:13 cases of spontaneous resolution of SBC were found. The clinical and radiographic characteristics of the cases coincide with the literature. 54% of cases had spontaneous resolution in a period of 5 years or less.Conclusion:In the case presented, radiographic follow-up of the patient was performed, demonstrating that following-up can be considered as treatment, since the lesion could resolve spontaneously.(AU)

Pathological fracture of a solitary bone cyst in the calcaneus: a case series and literature review.

INTRODUCTION: Solitary bone cysts in the calcaneus (calcaneal bone cysts) are often asymptomatic. Pathological fractures are rare, and few reports are available concerning its risk assessment. Therefore, the indication for operative interventions remains debatable, and further discussion on the treatment of symptomatic cysts and pathological fractures in calcaneal bone cysts is necessary. MATERIALS AND METHODS: Clinical data of 21 patients with calcaneal bone cysts (16 men and five women) was retrospectively reviewed. The average age was 13.3 (range, 7-23) years. Clinical data, such as concerning symptoms, radiological findings, pathological findings and outcomes, were investigated, and the pathogenesis of symptomatic cysts was studied. RESULTS: Thirteen cysts were symptomatic, and eight were incidentally discovered. Computed tomography revealed no fracture in 12 cases, microfracture in eight and complete fracture in one. The areas under the curves of the receiver operating characteristic curves calculated to establish an association between cyst size and symptoms and cyst size and pathological fractures (microfracture and complete fracture) were 0.78 and 0.71, respectively. Symptomatic cysts and pathological fractures were associated with the cyst ratio (cyst size/calcaneus ≥ 0.20). On magnetic resonance imaging (MRI), fluid levels were observed in 11 of 21 (52%) patients. At the time of surgery, blood from the haemorrhage was aspirated from 15 of 21 (71%) cysts. CONCLUSIONS: Orthopaedic surgeons should be aware that the cyst ratio is associated with clinical symptoms and pathological fractures. MRI and gross findings revealed haemorrhage in the cystic fluid. In calcaneal bone cysts, repeated microfractures and spontaneous healing might occur.

Analysis on Biomechanical Relationship Between Calcaneal Cyst Lesion Size and Pathological Fracture / 医用生物力学

Objective To investigate the relationship between lesion size of solitary bone cyst ( SBC) and pathological fracture of calcaneus, so as to provide references for the treatment of SBC. Methods The three dimensional (3D) finite element model of foot and ankle was established based on CT images. Four models with gradient spherical bone defects were constructed in the focal area to simulate different SBC lesion sizes, and the biomechanical characteristics of calcaneus in different gait phases were analyzed. Results With the increasement of SBC size, the kinematics of calcaneus did not change significantly, but the peak stress of calcaneus increased gradually. When the SBC size exceeded 75% of the calcaneal width, the stress in calcaneal sulcus and cortical bone below SBC increased by 1. 48 times and 7. 74 times, respectively. Conclusions The risk of pathological fracture increases when the SBC diameter exceeds 75% of the calcaneal width, and early surgical intervention should be recommended. The calcaneal sulcus and the cortex bone below SBC are stress concentration regions and can be used as important areas to evaluate pathological fractures.

High tartrate-resistant acid phosphatase (TRACP 5b) level in cystic fluid is a significant prognostic marker for postoperative recurrence in solitary bone cysts.

Purpose: The pathogenesis of cystic fluid storage in solitary bone cysts remains unclear. We aimed to compare the results of the biochemical analysis of cystic fluid with clinical findings. We identified a significant marker of postoperative recurrence. Methods: Twenty-seven male and eight female patients were studied; the median age at diagnosis was 11 (5-23) years. The mean follow-up period was 60 months (range: 14-146 months). Clinical information including sex, age, affected site, radiological findings of phase (active or latent), surgical procedure, outcome, and biochemical analysis of serum and cystic fluid was obtained. Results: The 5-year healing rate was 64.0%. Biochemical analysis revealed that total protein and albumin values in the cystic fluid were significantly lower, compared to those in the serum. Levels of bone turnover markers, such as alkaline phosphatase, bone-specific alkaline phosphatase, and tartrate-resistant acid phosphatase 5b were remarkably elevated in the cystic fluid than in the serum. R values were 0.127, 0.076, and 0.095 for alkaline phosphatase, bone-specific alkaline phosphatase, and tartrate-resistant acid phosphatase 5b, respectively. Areas under the receiver operating characteristic curves, calculated to assess the association of alkaline phosphatase, bone-specific alkaline phosphatase, and tartrate-resistant acid phosphatase 5b levels in the cystic fluid with postoperative recurrence, were 0.57, 0.51, and 0.70, respectively. Conclusions: No clear correlation of bone turnover marker levels between the serum and cystic fluid was observed. The high tartrate-resistant acid phosphatase 5b level in the cystic fluid was associated with postoperative recurrence. The bone resorption caused by osteoclasts is considered to affect postoperative recurrence. Level of evidence: Level IV.

Current strategies for the treatment of solitary and aneurysmal bone cysts: A review of the literature.

This review of the literature aims to compare the etiology, the pathogenesis, the clinical diagnostics and the relevant treatment options of two different types of cystic bone lesions: the solitary bone cyst (SBC) and the aneurysmal bone cyst (ABC). Whereas the clinical symptoms and the radiographic appearance can be similar, the diagnostic pathway and the treatment options are clearly different. The solitary bone cyst (SBC) represents a tumor-like bone lesion, occurring most frequently in the humerus and femur in children and adolescents. Pain caused by intercurrent pathological fractures is often the first symptom, and up to 87% of the cysts are associated with pathological fractures. In the majority of cases 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. Pain under weight bearing or regaining the ability to mobilize after fracture timely can necessitate surgical treatment in SBCs affecting the lower extremity. Spontaneous resolution can be seen in rare cases. The aneurysmal bone cyst (ABC) is a benign, locally aggressive tumor that occurs in childhood and early adulthood. It usually affects the metaphysis of long bones but can also occur in the spine or the pelvis. ABC can be primary but also secondary to other bone pathologies. The diagnosis has to be confirmed by biopsy and histopathological examinations. With cytogenetic studies and the detection of specific translocations of the ubiquitin-specific protease (USP) 6 gene primary ABCs can be differentiated from secondary ABCs and other bone lesions. Among various modalities of treatment i.e. en bloc resection, intralesional curettage with adjuvants, embolization or the systemic application of denosumab, intralesional sclerotherapy using polidocanol is an effective and minimally invasive treatment of primary ABCs.

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 Like Areas in Myositis Ossificans: A Breast Mass in a Child.

BACKGROUND: 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.

[Tumor-like bony lesions of the skeleton]. / Tumorähnliche Knochenläsionen des Skeletts.

Tumor-like bony lesions are, by definition bony lesions, which can be clinically, radiologically and histologically mistaken for real bone tumors. This article presents the aneurysmal bone cyst (ABC), solitary bone cyst (SBC), fibrous dysplasia, osteofibrous dysplasia Campanacci and non-ossifying fibroma (NOF). Many tumor-like bony lesions are often incidental findings. The combination of X­ray imaging specifically supplemented by magnetic resonance imaging (MRI) or computed tomography (CT) enables a diagnostic classification in the majority of cases.

[Tumor-like bony lesions of the skeleton]. / Tumorähnliche Knochenläsionen des Skeletts.

Tumor-like bony lesions are, by definition bony lesions, which can be clinically, radiologically and histologically mistaken for real bone tumors. This article presents the aneurysmal bone cyst (ABC), solitary bone cyst (SBC), fibrous dysplasia, osteofibrous dysplasia Campanacci and non-ossifying fibroma (NOF). Many tumor-like bony lesions are often incidental findings. The combination of X­ray imaging specifically supplemented by magnetic resonance imaging (MRI) or computed tomography (CT) enables a diagnostic classification in the majority of cases.

A large maxillary cemento-ossifying fibroma superimposed with solitary bone cyst documented over 18 years: A case report.

INTRODUCTION: Cemento-ossifying fibromas are rare, benign lesions of the head and neck regions. The origin of these lesions can be traced to the periodontal ligament, because its cells are able to form cement, lamellar bone, or fibrous tissue. CASE PRESENTATION: A rare case report of a young Caucasian female with a COF is described including follow-ups. She remained untreated for several years despite early radiographic findings of the lesion without a definitive diagnosis. The patient ultimately underwent radical surgery and the whole lesion was removed. The subsequent histological examination confirmed the clinical diagnosis of a COF. Since then, the patient has been under regular clinical and radiological follow-ups. DISCUSSION: This rare case report of a COF, documented over 18 years, shows the importance of consecutive therapy after radiologic and clinical findings, as such lesions continue growing and may subsequently lead to severe medical conditions. Therefore, complete surgical resection of COFs is advised to achieve good results in terms of health and recurrence. CONCLUSION: Long-term follow-up of patients is required as recurrences can occur for up to 10 years following treatment. Well-planned radical and wide surgical resection of these lesions has proven not only to be effective in eliminating the aetiological factors, but can also achieve decent bone regeneration and aesthetic results with almost no deformation in the surgical site.

Possible pathogenesis of calcaneal bone cysts.

INTRODUCTION: Recent literature indicates that calcaneal bone cysts have different clinical features compared to long bone cysts. Yet, previous studies have mainly focused on pathogenesis of long bone cysts. In this study, the pathogenesis of calcaneal bone cysts was investigated from radiological and pathological findings. MATERIALS AND METHODS: Patients comprised 18 males and 6 females diagnosed with calcaneal bone cysts at a median age ± standard deviation of 13.0 ± 3.6 years. Plain radiographs, computed tomography, magnetic resonance imaging, cystography, bone scintigraphy, and pathology were reviewed. RESULTS: All cysts occupied the central triangular area of the bone, with six extending posteriorly and two developing anteriorly. Fifteen of 20 cases (75%) showed the expanded foramen structures at the anterior margin of the posterior facet. According to cystography, four cysts showed absence of leakage to subtalar joint. Cystic fluid caused chronic haemorrhaging in 18 cases and pathologically detected cholesterol clefts were noted in 14 cases. DISCUSSION: The location of the expanded foramen structures was consistent with the nutrient foramens of the sinus tarsi artery in the unaffected population. Hence, initial cysts may originate from the collapse of the sinus tarsi artery. Subsequent haemorrhage may extend into the central triangle area, which is biomechanically free of stress. Because of poor bone remodelling, degenerative change of the haemorrhage is prolonged. The results of this study showed that circulation collapse of the sinus tarsi artery and mechanical factors are important in the formation of calcaneal bone cysts.

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 ß-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.

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.

Cisto ósseo solitário em mandíbula: relato de caso clínico / Solitary bone cyst of the mandible: clinical case report

Objetivo: apresentar um caso clínico de paciente com cisto ósseo solitário em mandíbula e sua evolução após o tratamento de exploração e curetagem cirúrgica por meio de achados radiográficos. Caso clínico: paciente do sexo masculino, 45 anos, compareceu à clínica da Faculdade de Estudos Administrativos ­ Fead. Ao exame clínico, os tecidos se apresentavam dentro dos padrões de normalidade e ao exame radiográfico observou-se área radiolúcida unilocular, limites regulares e bem definidos em região anterior de mandíbula entre ápices dos dentes 33, 32, 31, 41 e 42, sem deslocamento desses. Para confirmação do diagnóstico, além do exame clínico, foi necessário realizar a tomografia de feixe cônico e exploração cirúrgica. Após a exploração cirúrgica foi realizada a curetagem das paredes ósseas e a proservação do caso para acompanhar a sua evolução. Considerações finais: por ser uma lesão de comportamento não agressivo, responde bem a este tipo de tratamento, sendo notável sua melhora durante o período de acompanhamento.(AU)

Objective: To present a clinical case report of a patient with solitary bone cyst of the mandible and its evolution after exploration and surgical curettage treatment through radiographic findings. Case report: A 45-year-old male patient attended the clinic of the School of Administrative Studies - FEAD. The clinical examination showed normal tissues and the radiographic examination showed unilocular radiolucent area and regular and well-defined boundaries in the anterior mandible between the apexes of teeth 33, 32, 31, 41, and 42, without displacement. To confirm the diagnosis, in addition to the clinical examination, cone beam tomography and surgical exploration were required. After the surgical exploration, bone wall curettage and case proservation were performed to monitor the evolution. Final considerations: Considering it is a non-aggressive lesion, it responds well to this type of treatment, with considerable improvement during follow-up.(AU)

Expansile radiolucent lesion of the Temporomandibular Joint-A diagnostic enigma.

Radiolucent lesions of Temporomandibular Joint (TMJ) represent a diagnostic challenge and a treatment conundrum. Biopsy of the lesions is technically difficult owing to their complex anatomy. The Differential Diagnosis (DD) includes a wide array of lesions including Simple Bone Cyst, Ameloblastoma, Central Giant Cell Granuloma, Hemangioma, Osteoblastoma, Osteochondroma, Chondroblastoma, Chondrosarcoma, Neurofibroma and metastatic malignant lesions though none has a specific predilection for TMJ. Here we present a case report of a large expansile radiolucent lesion of right TMJ in a 22 year old male patient with difficulties involved in diagnosis and management. Though cystic lesion of TMJ is uncommon it is incumbent on the Maxillofacial Surgeon for an early diagnosis and prompt management.

Quiste óseo solitario maxilar y mandibular. Reporte de un caso y revisión de la literatura / Maxillary and mandibular solitary bone cyst. Case report and literature review

Resumen El quiste óseo solitario es una lesión benigna cuyo origen sigue siendo hasta hoy desconocido, siendo el traumatismo la principal teoría de su origen, atribuido a un sangrado intraóseo, el cual no permite la reparación ósea, lo que conlleva a la formación de una cavidad quística con contenido serohemático sin revestimiento epitelial siendo la mandíbula la más afectada en la mayoría de los casos; se presenta en pacientes entre 20 y 30 años, con prevalencia por género masculino, asintomática, de crecimiento lento y desplazamiento de corticales, pudiendo producir fracturas patológicas mandibulares, su hallazgo es incidental durante el examen radiográfico, observándose como una imagen radiolúcida uni- o multilocular, con bordes definidos, sin zona esclerótica. Estudios complementarios de tomografía y resonancia magnética, han mostrado que estas cavidades no necesariamente están ocupadas por líquido, sino que puede haber gas o estar vacías. Se debe de hacer diagnóstico diferencial con quiste dentígero, ameloblastoma, tumor odontogénico queratinizante, tumor odontogénico epitelial calcificante, tumor odontogénico adenomatoide.

Abstract Solitary bone cyst is a benign lesion of unknown origin up to the present date. Its origin is mainly attribute to trauma theory, caused by intra-osseous bleeding which prevents bone repair, causing thus a cystic cavity with serous hematic content lacking epithelial lining. In most cases, the lower jaw is the most affected. It is observed in patients with ages ranging 20-30 years, generally male, it is an asymptomatic, slow-growing entity which progresses toward the cortical plates; it can cause pathological mandible fractures. Its discovery is usually incidental during a radiographic examination. It appears as a radiolucent, unilocular ormultilocular image, with well -defined borders, lacking sclerotic areas. Additional tomography and magnetic resonance studies have revealed that these cavities are not necessarily taken up by fluids: there can be presence of gas, or they could be empty. A differential diagnosis must be established to discard dentigerous cysts, ameloblastoma, keratinizing odontogenic tumor, calcifying epithelial tumor or adenomatoid odontogenic tumor.

An unusual case of proximal humeral simple bone cyst in an adult from secondary cystic change.

BACKGROUND: Simple bone cysts (SBC) have been documented to occur in adults with closed physeal plates, most commonly affecting the calcaneus in this patient subset. Although most authors theorize an association to trauma, etiology of simple bone cysts remains an enigma up to now. CASE PRESENTATION: A 26-year-old kickboxing coach sought consult for a painful right shoulder which on radiographs and magnetic resonance (MR) imaging showed a proximal humeral lesion with signs of ossification. The patient was lost to follow-up but again sought consult after 3 years for the recurring complaint. On repeat radiographs, computed tomography (CT) scan, and MR images, tumor enlargement with cystic findings typical of simple bone cyst were documented. Diagnostic aspiration of the lesion was firstly done, revealing straw-colored fluid. The patient then underwent intralesional curettage with alpha-tricalcium phosphate cement reconstruction of the lytic defect. No perioperative complications were incurred, and on latest follow-up at 3 years postoperatively, Musculoskeletal Tumor Society (MSTS) and visual analog scale (VAS) pain scores were 30/30 and 0/10, respectively. CONCLUSIONS: The authors believe their report provides support to a possible association to trauma of simple bone cysts occurring in the adult population with closed physes and suggest this subset of patients may require a different treatment approach from that for juvenile simple bone cysts.

Solitary bone cyst of a lumbar vertebra treated with percutaneous steroid injection: a case report and review of literature.

PURPOSE: We describe a rare case of solitary bone cyst involving the vertebral body of L4. INTRODUCTION: To the best of the authors' knowledge, only 15 cases of solitary bone cysts involving the spine have been reported previously. All the reported cases were treated surgically, including resection and curettage with or without bone grafting. In the current case, treatment was with steroid injection alone. METHOD: A cystic lesion involving the vertebral body of L4 was identified in a 16-year-old girl with persistent low back pain of 2 years' duration. According to the radiological characteristics of the lesion, a diagnosis of solitary bone cyst was suspected. The patient underwent surgical intervention with percutaneous steroid injection alone since there was no evidence of thinned cortex or pathological fracture. The patient was discharged 2 days after this intervention with resolution of the low back pain. RESULT: At the final follow-up 7 months after treatment, the patient was asymptomatic and the beginning of bony healing was evident. CONCLUSION: Herein, we reported an extremely rare case of solitary bone cyst involving the body of the fourth lumbar vertebra. Local steroid injection should be considered as a minimally invasive intervention for a solitary bone cyst involving the spinal column with no evidence of thinned cortex or pathological fracture.