Myositis ossificans (MO) is a reactive, localized, benign lesion that typically affects the extremities in younger people. It is a unique and uncommon condition that has been difficult to fully understand regarding its causes, development, and effective treatment. Commonly seen in muscles of arms, and thighs, it seldom includes the masticatory muscles. Severe trismus results if it affects the masticatory muscles. Magnetic resonance imaging and computed tomography scans are useful methods for identifying the calcified mass. Histopathology is essential for achieving an accurate diagnosis and planning subsequent treatment strategies. This report describes the case of a 30-year-old male patient who came with a complaint of pain during mouth opening for 1 month.

BackgroundThis study evaluated the therapeutic efficacy of a novel percutaneous Kirschner wire (K-wire) fixation combined with the K-Hammer technique in pediatric patients with supracondylar humeral fractures.MethodsThis retrospective cohort study included 34 pediatric patients [13 males (38.24%); 21 females (61.76%); mean age 5.82 ± 2.54 years] with acute extension-type supracondylar humeral fractures (diagnosed ≤7 days post-trauma). Under general anesthesia, fractures underwent fluoroscopy-guided closed reduction and percutaneous fixation: two lateral-entry 1.5–2.0 mm K-wire provided initial stabilization, followed by a third medial-entry K-wire inserted using the K-Hammer technique to achieve a biomechanically optimized cross-pinning configuration. Postoperatively, the elbow was immobilized in a 90° functional position with a long-arm fiberglass cast for 4 weeks.ResultsOver a mean follow-up of 12.24 ± 4.45 months (range: 6–23 months), functional outcomes per Flynn's criteria were excellent in 32 patients (94.12%), good in 2 (5.88%), and fair in 0 (0%). No cases of secondary displacement, osteonecrosis, or major complications—such as nonunion, iatrogenic neurovascular injury, myositis ossificans, or chronic elbow dysfunction—were observed during postoperative monitoring.ConclusionsThe K-Hammer-assisted medial K-wire insertion provides a streamlined, reproducible approach for managing irreducible extension-type pediatric supracondylar humeral fractures. It effectively mitigates iatrogenic ulnar nerve injury, minimizes soft tissue trauma, ensures biomechanical stability, and promotes optimal long-term elbow kinematics.

This case documents a rare occurrence of heterotopic mesenteric ossification (HMO) identified at autopsy, highlighting the long-term sequelae of prior abdominal trauma and expanding awareness of this uncommon entity in forensic pathology. HMO, also called intraabdominal myositis ossificans, is a subset of myositis ossificans traumatica and is characterized by the abnormal formation of osseous, cartilaginous, and sometimes bone marrow elements. It is generally associated with trauma or previous abdominal surgeries and can lead to potential life-threatening complications. Autopsy findings may highlight the presence of extensive ossified tissue formation in the mesentery, along with signs of the associated complications. Due to the rarity of these findings, the diagnosis at autopsy is challenging. In the present case report, the body of a 34-year-old Black male who died of multiple gunshot wounds was examined at the Cook County Medical Examiner's Office. He had a history of remote abdominal multiple gunshot wounds with subsequent exploratory laparotomy. During the post-mortem examination, dense fibrous adhesions were noted in the abdominal cavity and multiple fragments of ossified tissue were removed from the mesentery. The observed findings were suggestive of HMO. Radiological imaging can reveal early ossification within weeks of trauma, while histopathological analysis confirms the diagnosis, showing mature lamellar bone with minimal atypia. This case highlights the importance of recognizing and considering this rare entity in the differential diagnosis when no apparent causes of death are detected at autopsy.

Neurogenic Myositis Ossificans (NMO) is a rare form of heterotopic ossification that occurs in approximately 10–20% of patients with severe central nervous system injuries, most commonly after traumatic brain or spinal cord injury. It is characterized by ectopic bone formation within periarticular soft tissues, leading to pain, swelling, and progressive joint stiffness. We report the case of a 54-year-old male who developed a paraplegia after a spine injury. Radiographs revealed early periarticular calcifications that progressively matured into well-organized ossifications on CT, showing cortical and trabecular differentiation without continuity with the adjacent skeleton—features typical of NMO. Laboratory tests showed elevated alkaline phosphatase with no systemic inflammation. The patient was managed conservatively with anti-inflammatory therapy and physiotherapy, resulting in stabilization of the ossifications but no functional recovery. This case illustrates the characteristic imaging evolution of NMO and emphasizes the radiologist’s key role in early diagnosis, differential assessment, and follow-up to guide appropriate multidisciplinary management.

IntroductionSwelling in the short external rotator muscles (SERMs) in patients with cerebrovascular disease may regress to non-traumatic myositis ossificans. This study investigates the temporal changes in CT findings of myositis ossificans, aiming to provide exploratory insights for diagnostic accuracy and clinical management.MethodsWe retrospectively reviewed 1,469 CT examinations of the pelvis conducted at our institution between 2001 and 2023, totaling 436 cases of cerebrovascular disease. We selected 20 patients showing swelling of SERMs, including six patients with bilateral swelling. Of the 20, only patients with at least one follow-up CT, six cases (eight hip joints), were selected for analysis, including two cases with bilateral involvement. The intervals between swelling, calcification, and ossification were calculated, with calcification defined as a high-attenuation area (≥100 HU) and ossification as peripheral calcification with internal fat density.ResultsAll eight hip joints exhibited calcification, either concurrently or sequentially with swelling. The mean interval from swelling to calcification was 12 ± 5.3 days, and 112 ± 102 days from swelling to ossification in six hips that developed ossification. In two hip joints, calcification disappeared without ossification developing. In all cases, the affected hip corresponded to the side of the paralyzed lower limb. On initial examination, all patients exhibited fever, two with fever of unknown origin.ConclusionThis study determined temporal progression in CT findings of myositis ossificans in swelling of SERMs of patients with cerebrovascular disease. Further, detecting swelling, calcification, or ossification in SERMs in follow-up CT is informative in excluding infections or neoplastic conditions.

ABSTRACTAtraumatic myositis ossificans in the head and neck is rare and diagnostically challenging. Its rapid growth, frequently inconclusive biopsies, and nonspecific imaging findings can mimic malignancy, such as sarcoma, leading to potential misdiagnosis. Awareness of this entity is crucial for clinicians to avoid unnecessary overtreatment and ensure appropriate management.

Muscle injuries are among the most prevalent musculoskeletal conditions in athletes, contributing significantly to morbidity and time lost from competition. The use of ultrasound (US) is advantageous in assessing these injuries due to its low cost, accessibility, portability, dynamic real-time capabilities and utility in prognosis and rehabilitation planning. This state-of-the-art review offers a comprehensive synthesis of current evidence on the anatomical, technical and clinical aspects of diagnostic US in evaluating sports-related muscle injuries. Key topics include the differentiation between direct and indirect injury mechanisms, classification systems, prognostic indicators and common complications such as fibrosis, haematoma and myositis ossificans. Emphasis is placed on a practical, stepwise approach to US examination and reporting, incorporating anatomical detail and functional assessment to support individualised return-to-play decisions. Despite certain limitations, the US remains a cornerstone imaging modality in sports medicine. Emerging technologies, including advanced imaging techniques, hold promise for enhancing diagnostic accuracy and optimising clinical outcomes.

Myositis Ossificans (MO) is a benign lesion in which bone tissue forms within muscle or soft tissue after a traumatic injury. It most commonly occurs in the extremities, large muscle groups and demographically in young adults, with a higher incidence in women. 60–75% of cases are associated with trauma. To achieve an accurate diagnosis of suspected soft tissue lesions, different imaging methods need to be evaluated. In cases where imaging findings are insufficient, biopsy may be required for histopathological confirmation. This case report aims to emphasize the following: 18F-Fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) should be considered in the differential diagnosis of soft tissue tumors, the diagnostic importance of the CT component in 18F–FDG PET-CT, and the crucial role of a detailed medical history in reaching a diagnosis.

This case study demonstrates the effectiveness of early surgical excision of the traumatic myositis ossificans of the vastus intermedius muscle in an elite football player and return to sports activity within 3months from the initial injury. A 27-year-old male professional football player presented with progressive pain and loss of range of motion after sustaining a severe, right quadriceps contusion 4weeks earlier. After unsuccessful conservative therapy, the differential diagnosis of myositis ossificans was suspected and confirmed on radiographic examination. MRI revealed significant edema encompassing a substantial portion of the vastus intermedius muscle. Surgical treatment was considered for the right thigh mass, being symptomatic 1month after the onset and refractory to conservative treatment and rehabilitation program. At 2months postsurgery, the patient was asymptomatic and had completed a rehabilitation program. Early surgical treatment followed-up with a rehabilitation program results with a complete recovery of muscle strength and range of motion. At 3months postinitial injury, the patient was considered fully recovered and had returned to the match without reporting pain or other symptoms.

Osteochondroma (OC) is a benign bone tumor commonly found near the ends of long bones. While spinal and hip localizations are rare, bilateral hip involvement is often associated with hereditary multiple exostoses, occurring in 30% to 90% of such cases. This report describes a unique case of bilateral hip OC developing after a spinal cord injury, in the absence of family history or hereditary multiple exostoses. A 35-year-old male presented with painful bilateral hip swelling and restricted mobility following a rural accident that caused a C6-C7 vertebral fracture with bilateral anterior dislocation of the articular facets. He also exhibited spastic tetraplegia and flexion contractures, with signs suggestive of femoral nerve compression. Initial imaging revealed myositis ossificans involving the iliopsoas and spinal muscles. A bone scan identified an immature osteoma. Histopathological examination following surgical excision confirmed the diagnosis of OC. The patient underwent spinal surgery 2 days after the trauma, followed by admission to a physical medicine rehabilitation unit. Surgical resection of the left hip lesion improved flexion, and a similar procedure on the right hip yielded temporary improvement but led to complications, including infection requiring antibiotics and drainage. Despite surgical interventions, tumor recurrence occurred within 3 months. Imaging confirmed recurrent myositis ossificans and fluid collections. One year postinjury, neurological deterioration was noted, with spastic tetraplegia progressing from the C5 to C7 level and worsening lower limb spasticity. Valium was introduced for spasm management. This case highlights a rare occurrence of bilateral hip OC following spinal cord injury and raises important questions about trauma-induced mechanisms in OC pathogenesis. It suggests the need for further investigation into the relationship between spinal trauma, heterotopic ossification, and tumor development.

Myositis Ossificans Traumatica of the Masticatory Muscles Following Orthognathic Surgery

Diagnostic challenges in osteosarcoma arise in small biopsies with under-representation of the lesion and scant or absent osteoid matrix. This study aimed to validate the utility of SATB2 antibody in the diagnosis of osteosarcoma and differentiate it from its histological mimics. A total of 70 histologically proven cases of osteosarcomas and 97 other histological mimics were included in the study. IHC was performed using SATB2 monoclonal antibody. SATB2 antibody revealed nuclear positivity in all 70 (100%) cases of osteosarcoma. The majority of the conventional osteosarcomas (30 cases, 55.6%) showed 5+ score with a strong-staining intensity. Parosteal osteosarcomas and low-grade central osteosarcoma displayed less extensive staining compared to conventional osteosarcomas. The benign bone-forming tumors (osteoid osteoma and osteoblastoma) showed intense nuclear staining in nearly 100% of the cells. Fibrous dysplasia, osteofibrous dysplasia, callus formation, and myositis ossificans also showed nuclear positivity predominantly along the osteoid. Enchondromas and grade 1 and 2 conventional chondrosarcomas were negative. Positive staining was observed in phosphaturic mesenchymal tumor, juvenile trabecular ossifying fibroma, and desmoplastic fibroma. The other tumors like Ewing sarcoma, lymphoma, chordomas, and undifferentiated sarcomas were negative. Thus, SATB2 can be used to differentiate small-cell osteosarcoma from round-cell sarcomas and enchondroma and chondrosarcomas (grade 1 and 2) from chondroblastic osteosarcoma. It can be used as a useful adjunct in specific settings where osteoid is equivocal.

BACKGROUND. Post-traumatic myositis ossificans (MO) is a complication of observation characterized by bone formation in soft tissues. The lesion, proceeding in stages, according to clinical and visual manifestations, manifests itself at each stage. The diagnosis is established based on anamnesis, features and research methods, which can be informative depending on the stage of the disease. AIM: To present the possibility of computed and magnetic resonance imaging in the diagnosis of MO in children. METHODS: In this study we analyzed data from 68 children who had signs of MO according to radiological diagnostic methods. The average age of patients was 12.3±4.9, from 2 months to 17 years. There were 42 boys (61.76%), girls — 25 (38.24%). The cause of OM in the studied patients was damage to the musculoskeletal system (fractures, bruises of soft tissues) and/or impaired blood circulation in the muscles as a result of prolonged forced immobility during their stay in the intensive care unit, as well as in connection with the consequences of trauma (vegetative state, lower paraplegia). RESULTS: At the early stage of MO, classical radiographs in all 49 children were negative, at 4–6 weeks after injury, half of them had weak radiopaque changes in the surrounding space. CT showed initial soft tissue edema or volumetric changes, both with and without calcification at 4–6 weeks. In case of fuzzy zonal changes on CT and differential diagnosis MRI was performed in 34 children, which made it possible to solve problems with the diagnosis of MO. MO affected zones were identified in several anatomical areas: in 48 children out of 68, dysfunction of the muscles of the limbs was revealed, followed by the muscles of the pelvis (29 children) and upper limbs (14 children). CONCLUSION: Traumatic MO is capable of affecting any extraskeletal muscles. Our study showed that MO is more common in the anterior region of the thigh, which includes the quadriceps muscle group. For correct and timely MO diagnosis it needs to use several detection methods. CT is currently the best method for MO diagnosing. If the symptoms are not obvious on CT and there is a need for additional differential diagnosis, MRI should be performed.

Outcomes of posterior wall acetabular fractures with marginal impaction using greater trochanter autografting: A prospective cohort study.

Bone scintigraphy remains the second highest volume procedure in nuclear medicine laboratories with diverse applications. Bone scans are highly sensitive and can detect abnormalities much earlier than conventional X-rays. They provide a full-body image, allowing for the assessment of multiple bone sites simultaneously. they can also show specific patterns associated with specific diseases, eliminating ambiguity in diagnosis and establishing a specific diagnosis. Bone scan may be the final station to confirm the diagnosis of certain bone lesions that appear equivocal on other imaging modalities. There are some conditions where bone scans can be considered accurate and guide precise diagnosis, particularly when interpreted in conjunction with clinical findings and/or other imaging modalities as bone metastases, myositis ossificans, osteomyelitis, discitis, avascular necrosis, metabolic bone disease, fibrous dysplasia, osteopetrosis, stress fractures, Rheumatoid arthritis, reflex sympathetic dystrophy, transient migratory osteoporosis, hypertrophic osteoarthropathy, osteoid osteoma, condylar hyperplasia and osteopoikilosis.

Myositis ossificans (MO) is commonly characterised as a benign, self-limiting ossifying lesion in extraskeletal soft tissues. We present a case of MO of the clavicle in a 13 year old boy who did not have any history of preceding trauma. Multiple clinical investigations were required to reach the diagnosis of MO. Initial radiographic and imaging findings were inconclusive. Diagnosis was only achieved after biopsy and molecular study (COL1A1::USP6 gene fusion). Atraumatic MO presents a complex diagnostic challenge due to its close clinical similarity to bone and soft tissue tumours like osteosarcoma, requiring the correlation of histopathological and molecular findings with plain radiography and clinical observations. This was an exceedingly rare case of MO due to the location of the mass, the absence of a history of trauma and the patient’s age. To the best of our knowledge, there have been no previously published case reports of atraumatic MO of the clavicle in a paediatric patient.

Myositis ossificans (MO) is a rare entity of extra-skeletal bone formation in various muscles, most commonly in quadriceps, gluteals, small muscles of hand and brachialis, which often triggered by trauma or ischemia. It is first described in medical literature during the 17th–18th centuries, with early cases linked to traumatic injuries. Traumatic MO Formally classified by German pathologist Von Dusch in 1868. Historically, it was termed "rider's bone" due to its association with horseback riding injuries. Repeated trauma to the elbow from sports may be linked to the development of myositis ossificans traumatica (MOT). We report a case of MOT in a 26-year-old male who sustained non-traumatic ischemic compression during sleep and presented with severe pain and a fixed flexion deformity of the elbow. The patient typically presented as a painful, tender, enlarging mass, which was located in anterior distal humerus within brachial muscles of the upper arm, following subtle repetitive local trauma. Although it seems unnoticed, causing ischemia alteration in brachial muscles while he was sleeping on his volar aspect of the elbow for several months. Imaging studies, including ultrasound, X-ray, CT and MRI, revealed a bony mass in the anterior aspect of the right elbow and a history of brachial ischemia caused by sustained pressure. Biopsy histology and molecular biology studies confirmed the diagnosis of MOT. Clinically, MO may present as a painful soft-tissue mass, which could be confused with tumor or inflammatory lesions. MO goes through different phases of evolution, and its appearance on imaging varies depending on the stage of investigation. For differentiation diagnosis from soft-tissue tumors or other malignancies, comprehensive image studies and histology, molecular biology studies are compulsory.

Myositis ossificans traumatica of the masticatory muscles following orthognathic surgery: a case report

Myositis ossificans is a non-neoplastic ossifying mass seen in association with a bony and soft tissue trauma. We present a case of myositis ossificans mass developed after a distal humerus fracture mimicking the shape of lateral humeral condyle which led to inappropriate fixation of implant over the mass. Preoperative planning, extensile surgical approach, complete excision of the mass and use of image intensifier are highlighted which will avoid complications like failure of fixation and recurrence.

Myositis ossificans (MO) is a benign soft tissue lesion, characterized by ectopic ossification due to inappropriate fibroblast differentiation, most commonly affecting skeletal muscles. It often occurs in young adults after muscle trauma, predominantly in male patients and very rarely in children. We describe the case of a previously healthy 3-year-old boy who developed a lesion in his deltoid muscle after vaccination against tick-borne encephalitis. During an MRI scan, performed under general anesthesia, fine needle aspiration biopsy (FNAB) and core needle biopsy (CNB) were performed. While the CNB sample resulted in a non-diagnostic finding, the FNAB sample showed cytomorphology consistent with the diagnosis of MO. A molecular analysis performed on the FNAB sample confirmed the presence of COL1A1::USP6 fusion, which is considered diagnostic for MO in the appropriate clinical context. The boy was then referred to the orthopedic surgeon. Extracorporeal shock-wave therapy was chosen as the first-line treatment, but as it was too painful, the lesion was surgically removed, and histopathologic evaluation confirmed the diagnosis. Although rare in children, the diagnosis of MO should be considered in soft tissue lesions after trauma. We present the first pediatric case of MO diagnosed by FNAB and propose that FNAB, as a minimally invasive diagnostic procedure, is a suitable diagnostic approach, especially when molecular testing is available to confirm the diagnosis.