Soft tissue aneurysmal bone cysts (STABCs) are rare neoplasms histopathologically identical to aneurysmal bone cysts. These benign lesions are characterized by thin, peripheral ossification and no skeletal continuity. STABC may be difficult to distinguish from myositis ossificans (MO) and malignant entities from imaging and fine needle aspiration, due to rarity and overlapping features. We present a case of a STABC occurring in the paraspinal cervical muscles. The imaging, histopathology, molecular analysis, and treatment are discussed. Four other published cases of STABC of the head and neck are reviewed.

OBJECTIVE: Aneurysmal bone cysts (ABCs) are benign but aggressive vascular lesions within bone. Orbital ABCs, though rare, are clinically significant due to the risk of debilitating symptoms such as vision loss.
METHODS: Our systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using PubMed, Google Scholar, Embase, and SCOPUS databases to identify and assess primary articles exploring orbital ABC cases. Additionally, we present an illustrative case report.
RESULTS: Among the 54 cases from the 51 studies included, the mean age was 16.87 years, with 23 males, 29 females, and 2 unspecified. The most prevalent symptoms were exophthalmos (N = 36) and diplopia (N = 21). Regarding laterality, the right orbit was most commonly affected (N = 27), followed by the left orbit (N = 21), with four cases of bilateral involvement. Within the orbit, the medial wall most frequently impacted location (N = 14), followed by the orbital roof (N = 13), posterior wall (N = 7), lateral wall (N = 3), and orbital floor (N = 2), with 15 cases involving multiple locations. Surgical resection was the primary treatment, resulting in complete resolution in 44 cases. In our case, a 30-year-old male with an orbital aneurysmal bone cyst was managed surgically through bifrontal craniotomy with superior orbitotomy for lesion excision and orbital roof reconstruction.
CONCLUSIONS: Aneurysmal bone cysts in the orbit can be challenging, and complete removal of the lesion is essential for achieving optimal patient outcomes.

Aneurysmal bone cysts (ABCs) are rare benign bone lesions with a predilection for the metaphysis of long bones. They are often cystic, expansive, and osteolytic and may result in bony deformity. In general, there remains debate about optimal treatment for ABCs; however, the mainstay typically consists of a combination of curettage, bone grafting, and considering the need for internal fixation and osteotomies. The goals of treatment include preserving bony anatomy while eliminating the lesion. There is sparse literature regarding the treatment of osteoarthritis adjacent to benign bony tumors. If total hip arthroplasty is chosen as a treatment option, diligent preoperative planning is required, and the surgeon must assess the patient\'s bone stock, account for bony deformity, and utilize specific implants and techniques based on the patient\'s characteristics. We present a case of an adult patient with proximal femur ABC and symptomatic adjacent hip osteoarthritis who underwent treatment with total hip arthroplasty.

Tumors that develop on the chest wall are usually rare. This case report highlights a rare occurrence of a giant cell tumor originating from the anterior arch of the fourth rib. The patient, a 21-year-old male, presented with a bulging mass that had been gradually increasing in size over an eight-month period, reaching dimensions of 12 x 8 cm. Despite the noticeable swelling, the patient reported no associated pain or discomfort and denied any history of weight loss or trauma. The absence of chest pain or cardiovascular symptoms distinguished this case from other chest wall pathologies. This report underscores the importance of considering rare entities such as giant cell tumors in the differential diagnosis of chest wall masses, especially in cases where clinical presentation and patient history do not align with more common conditions.

UNASSIGNED: Aneurysmal bone cysts (ABCs) are aggressive, expansile, and locally destructive vascular lesions. The exact etiology of ABCs is currently unknown and hypothesized to be related to vascular malformations or disruption of osseous vascularity. To date, there have been no reports describing the development of pubic ABCs following penile inversion vaginoplasty (PIV).
UNASSIGNED: This report describes the development of a pubic ABC in a transgender patient who had previously undergone PIV, possibly indicating a very rare complication of this gender-affirming operation.
UNASSIGNED: A 37-year-old transgender female was initially referred to the orthopedic oncology clinic for evaluation of a 12-month history of left hip and groin pain. She had undergone gender-affirming PIV about 19 months prior to presentation. Magnetic resonance imaging (MRI) with contrast revealed a low T1 signal intensity and heterogenous T2 hyperintensity 7.5 × 4.9 × 4.3-cm destructive mass in the left superior pubic ramus extending across the pubic symphysis into the right superior pubic ramus. A needle core bone biopsy demonstrated a variably cellular spindle and round lesion with islands of osteoid formation and focal necrosis. The cells were negative for CD34, S100, and desmin. There was no evidence suggesting osteosarcoma, and final review favored the diagnosis of an ABC. Given the highly destructive nature of the mass, it was resected, and the resulting wound was reconstructed with a biologic dermal mesh.
UNASSIGNED: Although it is impossible to distinguish coincidence from causation in this case, the patient\'s recency of PIV and development of a rare ABC in a nearby bone warrants the speculation and discussion provided in this report.

BACKGROUND: Aneurysmal bone cysts (ABCs) are benign, osteolytic lesions that can occur in long bones, vertebrae, or rarely, the skull. Here the authors present the case of a 15-year-old male with a primary ABC of the left frontoparietal skull along with a review of the literature to provide insight into the nature of this rare disease.
METHODS: An otherwise healthy 15-year-old male presented with a tense, painful lesion of the left frontoparietal scalp. He could not identify any inciting trauma, but first noted the lesion less than 2 weeks prior to presentation with progressive enlargement. Cranial imaging revealed a lytic skull lesion with fluid-fluid levels suggestive of ABC. Curative therapy was provided via wide excision of the lesion and calvarial reconstruction of the resultant skull defect. This was performed without complication, and histopathological evaluation confirmed the diagnosis of primary ABC.
CONCLUSIONS: ABCs of the skull are rare entities and most often arise in the skull base versus the calvaria. Typically, these lesions are associated with an underlying bone pathology (secondary ABCs) but can be rarely seen as isolated lesions (primary ABCs). Clinical management consists of excision and adjuvant therapy for underlying pathology where appropriate.

UNASSIGNED: An aneurysmal bone cyst (ABC) is an unusual, non-cancerous bone lesion that is characterized by its lytic (causing bone loss), hemorrhagic, and expanding nature. ABCs are relatively rare, making up only 1% of all bone tumors. These cysts are typically found in long bones and the spine but are very rarely seen in the metatarsal bones, making such occurrences quite uncommon.
UNASSIGNED: In this case report, we present a case of ABC of the 3rd metatarsal in a 26-year-old female with complaints of long-standing foot pain and gradually increasing swelling of the dorsum of the foot. After radiological evaluation, she had undergone histopathological evaluation. An en bloc resection of the metatarsal along with the tumor mass was performed and the gap was replaced with an ipsilateral fibular strut graft. Histopathological examination of the resected tissue was suggestive of ABC without any evidence of malignancy. At the end of 1 year of follow-up, she is now completely pain free with intact rom of foot and ankle.
UNASSIGNED: The present study aims to describe a case of ABC of the metatarsal, a condition that not only poses a diagnostic dilemma but also constitutes a challenge in the management of lesion.

UNASSIGNED: Spinal aneurysmal bone cysts (ABCs) are rare, histologically benign tumors with aggressive behavior, which may cause bone and soft-tissue destruction, particularly affecting neural elements. Management of these tumors, including treatment modalities and follow-up protocols, remains challenging.
UNASSIGNED: A 7-year-old boy presented with chest wall pain persisting for two months before admission, accompanied by progressive mono paresis lasting ten days before admission. Myelopathy signs were evident during the examination. Imaging confirmed a multicystic lesion at the T6 level involving the posterior elements of the vertebra, with significant cord compression. Due to deteriorating neurological function, he underwent urgent laminectomy and neural decompression, followed by subtotal tumor resection. Postoperative histopathological examination confirmed the diagnosis of an ABC, and the patient experienced significant neurological recovery. However, after 21 days, the patient was readmitted to the emergency department with severe paraparesis. Magnetic resonance imaging revealed rapid growth of the residual tumor, leading to cord compression. He underwent aggressive total tumor resection, T6 vertebral body corpectomy, and fixation with pedicle screws and cage insertion. Following the second surgery, prompt neurological recovery occurred.
UNASSIGNED: This rare case report emphasizes the importance of a close follow-up protocol for spinal ABCs in the pediatric population. It highlights the challenges in managing these tumors and the need for vigilant monitoring to detect and address rapid recurrences.

BACKGROUND: Aneurysmal bone cyst (ABC) is an uncommon, benign, vascular multicystic bony lesion that most frequently develops in the first two decades of life. The metaphysis of long bones, pelvic, and vertebral column are the most common locations. The precise underlying pathophysiology of ABCs formation remains unclear; however, it is believed that reactive processes subsequent to trauma or vascular disturbance may play an important role. Involvement of the skull base rarely occurs with a prevalence of up to 5% of intracranial ABCs.
METHODS: An 18-year-old adolescent female with a history of progressive blurred vision since three months ago presented to our office. The brain and orbital MRI demonstrated no abnormal findings. After three months of glucocorticoid treatment with the diagnosis of multiple sclerosis, the visual impairment of the left eye deteriorated abruptly. The patient underwent an MRI and the imaging study demonstrated a well-defined 30 × 22 × 20-mm lesion at the anterior clinoid process with an extension to the optic canal and ethmoid sinus. The patient underwent pterional craniotomy, and the tumor was resected. The histopathological examination was suggestive of ABC.
CONCLUSIONS: ABC and other conditions should be considered in young-age people with an early unilateral decline in vision and imaging studies should be obtained in early stages and during follow-ups.

OBJECTIVE: We report a case of fibrous dysplasia (FD) with aneurysmal bone cyst (ABC)-like change in a child with orbital involvement, review the related cases, and discuss clinical features, therapy, and prognosis of this disease.
METHODS: A 10-year-old girl had right proptosis (degree of exophthalmos: OD 16 mm, OS 13 mm) and limited vision (visual acuity: OD 1.0, OS 0.8) without trauma. Preoperative CT showed a 5.0*4.3 cm right-sided crania-orbital communicating tumor. MRI indicated a well-defined multicystic mass with scattered fluid levels and soap bubble-like alterations. The child underwent total tumor resection and orbital parietal titanium mesh reconstruction. At 20 months of follow-up, the child has recovered from ocular problems, and the tumor has not recurred.
CONCLUSIONS: FD combined with ABC rarely occurs in orbit and generally begins with ocular symptoms. The etiology is uncertain. Early diagnosis and surgery are essential. Complete resection is suggested whenever possible because residual lesions may recur.