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Introduction. Nonhereditary heterotopic ossification (NHO) is a common complication of trauma. Progressive osseous heteroplasia (POH) and fibrodysplasia ossificans progressiva (FOP) are rare genetic causes of heterotopic bone. In this article, we detail the vascular patterning associated with genetic versus NHO. Methods. Vascular histomorphometric analysis was performed on patient samples from POH, FOP, and NHO. Endpoints for analysis included blood vessel (BV) number, area, density, size, and wall thickness. Results. Results demonstrated conserved temporal dynamic changes in vascularity across all heterotopic ossification lesions. Immature areas had the highest BV number, while the more mature foci had the highest BV area. Most vascular parameters were significantly increased in genetic as compared with NHO. Discussion. In sum, both genetic and NHO show temporospatial variation in vascularity. These findings suggest that angiogenic pathways are potential therapeutic targets in both genetic and nonhereditary forms of heterotopic ossification.

Background: Fibrodysplasia ossificans progressiva is an ultrarare autosomal dominant disorder and disabling syndrome characterized by postnatal progressive heterotopic ossification of the connective tissue and congenital malformation of the big toes. Fibrodysplasia ossificans progressiva has worldwide prevalence of about 1 in 2 million births. Nearly 90% of patients with fibrodysplasia ossificans progressiva are misdiagnosed and mismanaged and thus undergo unnecessarily interventions. So far, the number of reported existing cases worldwide is about 700. Clinical examination, radiological evaluation, and genetic analysis for mutation of the ACVR1 gene are considered confirmatory tools for early diagnosis of the disease. Association of fibrodysplasia ossificans progressiva with heterotopic ossification is well documented; however, postsurgical exaggerated response has never been reported previously, to the best of our knowledge., Case Presentation: We report a case of a 10-year-old Pakistani boy brought by his parents to our institution. He had clinical and radiological features of fibrodysplasia ossificans progressive and presented with multiple painful lumps on his back due to hard masses and stiffness of his shoulders, neck, and left hip. He underwent surgical excision of left hip ossification followed by an exaggerated response in ossification with early disability. Radiological examination revealed widespread heterotopic ossification. All of his laboratory blood test results were normal., Conclusion: Fibrodysplasia ossificans progressiva is a very rare and disabling disorder that, if misdiagnosed, can lead to unnecessary surgical intervention and disastrous results of early disability. We need to spread knowledge to physicians and patients' family members about the disease, as well as its features for early diagnosis and how to prevent flare-up of the disease to promote better quality of life in these patients.

Myositis ossificans traumatica (MOT) is a common form of heterotopic ossification associated to trauma. Rare mature manifestations and topographically atypical presentations of MOT are often misdiagnosed as osteosarcoma. This case study discusses a rare, mature case of MOT of the piriformis muscle, potentially clinically associated with piriformis syndrome. The ossification was observed on a dry sacral bone of an adult skeleton belonging to a South African male during routine inventory of the Raymond A. Dart Collection of Human Skeletons, the University of the Witwatersrand, Johannesburg. The MOT was located on the anterior aspect of the sacrum at a site corresponding to the upper portion of the origin of the muscle and extended laterally towards the greater trochanter, beyond the greater sciatic notch. It was cylindrical in shape and measured approximately 52.70 mm in length and 12.10 mm in diameter. Micro-focus CT revealed an extensive and mature bony development of the piriformis muscle with distinct outer cortical and inner trabecular bone. In addition, the skeleton showed widespread healed skeletal trauma, suggesting a history of trauma. The MOT was completely fused to the sacral bone excluding the possibility of congenital anomalies. Information on the MOT of the piriformis muscle is vital to clinicians and radiographers to aid in successful diagnosis and management of the piriformis syndrome and sciatica in the gluteal region. This case also provides a rare example to biological anthropologists, paleoanthropologists and bioarchaeologists of the representation of pathologies like these on a dry bone sample.

Myositis ossificans (MO) is an uncommon myofibroblastic proliferation that may closely mimic sarcoma. A 33-year old woman presented with a 2-cm breast mass. A core needle biopsy showed highly cellular spindle cell proliferations with atypia and high proliferation activity. Focal areas of immature osteoid-like matrix were seen. After immunohistochemical analysis, a diagnosis of metaplastic breast cancer was made. Because of the proximity of the tumor to the rib, resection of the tumor including partial resection of the rib was carried out. Complete examination of the excised lesion allowed the correct diagnosis of MO. Only the resection specimens contained a predominance of mature organoid bone tissue admixed with variably cellular myofibroblastic proliferations with the typical zonal pattern, characteristic of MO. The diagnosis of MO was not possible on the initially performed core needle biopsy because biopsy material reflected only the central proliferative portion of the lesion showing increased pleomorphism and early osteoid formation. This case highlights the pitfall related to this unusual presentation of a benign lesion and points to the necessity to include MO in the differential diagnosis of triple-negative metaplastic breast cancer., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The purpose of this case report is to show the clinical presentation of a rare genetic disorder, called fibrodysplasia ossificans progressiva, on the development of the foot in a newborn. Shortened great toes and malformations of the first metatarsals are present in all affected individuals at birth. Irreversible heterotopic endochondral ossification of soft tissues occurs in the first decade of life, often resulting in permanent immobility by the third decade of life. Trauma caused by surgical excision of nodules, dental procedures, or injections can further exacerbate this condition. Early diagnosis is imperative for these patients to prevent irreversible damage that may result from unnecessary invasive interventions. This case report presents a boy aged 2 years 3 months who was born with bilateral bunion deformity. The goal is to raise awareness of this disorder in the podiatric community, especially for those who work with pediatric patients.

Clinical trials for orphan diseases are critical for developing effective therapies. One such condition, fibrodysplasia ossificans progressiva (FOP; MIM#135100), is characterized by progressive heterotopic ossification (HO) that leads to severe disability. Individuals with FOP are extremely sensitive to even minor traumatic events. There has been substantial recent interest in clinical trials for novel and urgently-needed treatments for FOP. The International Clinical Council on FOP (ICC) was established in 2016 to provide consolidated and coordinated advice on the best practices for clinical care and clinical research for individuals who suffer from FOP. The Clinical Trials Committee of the ICC developed a focused list of key considerations that encompass the specific and unique needs of the FOP community - considerations that are endorsed by the entire ICC. These considerations complement established protocols for developing and executing robust clinical trials by providing a foundation for helping to ensure the safety of subjects with FOP in clinical research trials., (© 2018 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Introduction: Myositis ossificans (MO) is an ectopic ossification characterized by an appearance of bone formation predominantly in muscle tissue. Trauma is the most common etiological factor, observed in almost 60-75% of cases, whereas a non-traumatic MO is rarely described in the literature. A diagnosis is based on clinical and radiological findings., Presentation of Case: A 75-year old female patient has been admitted to our clinic with a localized swelling of the posterior femoral compartment, presented on magnetic resonance as a calcification in the biceps femoris muscle. Laboratory test results were within the normal range. Surgical procedure consisted of excision of the tumor mass with primary wound reconstruction and drainage. The post-operative period was uneventful, and the patient was discharged from hospital on the seventh postoperative day. The pathohistology findings have shown the MO., Discussion: A non-traumatic MO is scarcely described in the literature. A chronic microtrauma, tissue ischaemia and inflammation are listed as causal mechanisms of a non-traumatic MO. MO non-traumatica occurs more often in patients with a parallel, subdural or epidural haemorrhage and a hip surgery. Our case did not present any family history, trauma or associated anomalies of hands or fingers., Conclusion: Myositis ossificans should be considered as the differential diagnosis of all soft tissue tumor masses, even if known risk factors are not present in the anamnesis. Surgery is a reasonable therapeutic strategy in the presence of a tumor mass in soft tissues, and definite diagnosis can be set only based on pathohistological findings., Key Words: Ectopic ossification, Non traumatic myositis, Surgery.

Fibrodysplasia ossificans progressiva (FOP) is a rare human skeletal disease caused by constitutively activating mutations in the gene ACVR1, which encodes a type I BMP/TGFβ family member receptor. FOP is characterized by progressive heterotopic ossification (HO) of fibrous tissues, including skeletal muscle, tendons, and ligaments, as well as malformation of the big toes, vertebral fusions, and osteochondromas. Surgical interventions in patients often result in enhanced HO, which can exacerbate rather than improve diagnostic outcomes. As a result of these difficulties, a variety of animal models are needed to study human FOP. Here we describe the methods for creating and characterizing zebrafish conditionally expressing Acvr1l Q204D , the first adult zebrafish model for FOP.

Background: Myositis ossificans describes a heterotopic bone formation within a muscle. Thereby myositis ossificans is classified in two different groups: myositis ossificans progressiva (MOP) which describes a genetic autosomal dominant rare disease and myositis ossificans traumatica (MOT). The exact pathogenesis of MOT is unclear. The aim of this article was to analyse and interpret the existing literature reporting MOT of masticatory muscles and compare the results with our own clinical experience with MOT. Risk-factors, etiology, clinical features, diagnostic imaging, as well as different treatment options were evaluated and recommendations for the prevention, diagnosis, and therapy of MOT of the masticatory muscles were given., Methods: Following the PRISMA-Guidelines, a systematic search within the PubMed/Medline database with a view to record literature of MOT of the masticatory muscles was performed. Furthermore, the database of our own clinic was screened for cases of MOT., Results: In total, 63 cases of MOT of the masticatory muscles which were reported in English-based literature were included in this study. Overall, 25 female and 37 male patients could be analysed whereas one patient's gender was unknown. Complication of wisdom-tooth infection (n = 3) as well as the results of dental procedures like dental extraction (n = 7), mandibular nerve block (n = 4), periodontitis therapy (n = 1) were reported as MOT cases. From the 15 reported cases that appeared after dental treatment like extraction or local anesthesia the medial pterygoid (n = 10) was the most affected muscle. Hereof, females were more affected (n = 9) than males (n = 6). The most reported clinical symptom of MOT was trismus (n = 54), followed by swelling (n = 17) and pain (n = 13). One clinical case provided by the authors was detected., Conclusions: Dental procedures, such as local anesthesia or extractions, may cause MOT of the masticatory musculature. Demographical analyses demonstrate that females have a higher risk of developing MOT with respect to dental treatment. The most important treatment option is surgical excision. Subsequent physical therapy can have beneficial effects. Nevertheless, a benefit of interpositional materials and drugs as therapy of MOT of the masticatory muscles has not yet been proven. Myositis ossificans progressiva has to be excluded.

Background: Fibrodysplasia ossificans progressiva (FOP), also known as Myositis ossificans progressiva or Munchmeyer's disease, is an extremely rare and disabling genetic condition of congenital skeletal malformations and progressive heterotopic ossification (HO). The disease is characterized by congenital skeletal anomalies and progressive ectopic bone formation in connective tissues such as ligaments, muscles and tendons. The disease has an incidence of about 1 in 2 million population., Case Details: We report a case of a 2-year and 8-month old male child with an initial diagnosis of soft tissue sarcoma based on fine needle aspiration (FNAC) of neck swelling., Conclusion: Fibroplasia ossificans progressive (FOP) characteristically manifests with bilateral malformation of the great toe and progressive heterotopic ossification (HO). Clinicians and radiologists should be aware of these to prevent permanent disability.

Heterotopic ossification (HO) involves the formation and accumulation of extraskeletal bone tissue at the expense of local tissues including muscles and connective tissues. There are common forms of HO that are triggered by extensive trauma, burns and other bodily insults, and there are also rare congenital severe forms of HO that occur in children with Fibrodysplasia Ossificans Progressiva or Progressive Osseous Heteroplasia. Given that HO is often preceded by inflammation, current treatments usually involve anti-inflammatory drugs alone or in combination with local irradiation, but are not very effective. Recent studies have provided novel insights into the pathogenesis of acquired and genetic forms of HO and have used the information to conceive and test new and more specific therapies in animal models. In this review, I provide salient examples of these exciting and promising advances that are undoubtedly paving the way toward resolution of this debilitating and at times fatal disease., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Myositis ossificans circumscripta (MOC) is a rare benign condition characterized by heterotopic ossification occurring in the soft tissues. We report the case of a 15-year old patient complaining of mixed hip pain. No trauma has been reported during the interview. The joint had inflammation appearance and a non-mobilizing swelling adhered to the deeper structure with parietal projection over the groin fold. Radiographs of the hip showed a thickening of the soft tissues of the hip and some periarticular calcifications with unclear appearance. Excisional biopsy of the calcifications was decided and performed. Diagnosis was confirmed by histological examination of the surgical specimen. At six months follow-up the patient was very satisfied with his functional results. Returning to school sports was authorized. The patient had successful outcome.

Fibrodyplasia ossificans progressiva (FOP) is an ultra-rare genetic condition of heterotopic ossification (HO) that results in progressive loss of joint function, ultimately rendering movement impossible. Death is most commonly the result of thoracic insufficiency syndrome, or complications related to recurrent respiratory infections. There are no current treatments for FOP, but early and emerging clinical trials offer hope for this devastating disease. With the recent reporting of a comprehensive global natural history study, scales to assess joint dysfunction, and a more accurate prediction of joint survival, it is now possible to construct a conceptual framework for the clinical staging of FOP. Based on assessment of FOP features in seven areas, it is possible to assign five clinical stages. FOP features include flare-up activity, body regions affected, thoracic insufficiency, other complications, activities of daily living (ADLs), ambulatory status, and the cumulative joint involvement scale (CAJIS) score. Assessments of these features assign an individual with FOP to early/mild, moderate, severe, profound, or late-stage disease. These criteria seek to be flexible enough to be used by clinicians without reliance on advanced imaging or specialized testing, as well as by investigators involved in research or clinical trial studies who would have these tools available. These staging measures for FOP assess the influence of HO and accelerated joint dysfunction (due to congenital abnormalities) on the ability to perform common functional activities, and thus a delay or lack of progression from one stage to the next represents the ultimate test of efficacy for drug trials. This framework will serve both as a prediction tool for FOP progression as well as a critical opportunity to substantiate therapeutic interventions. The staging system proposed here will permit an accurate assessment of severity to appropriately develop or revise clinical plans of care, define operational research criteria, and identify the effectiveness of interventions. Ultimately, this clinical staging will aid the field in moving toward earlier intervention at a stage where disease-modifying therapies may be most efficacious., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Flare-ups of the hips are among the most feared and disabling complications of fibrodysplasia ossificans progressiva (FOP) and are poorly understood. In order to better understand the nature of hip flare-ups in FOP, we evaluated 25 consecutive individuals with classic FOP (14 males, 11 females; 3-56years old, median age, 17years old) who presented with acute unilateral hip pain., Results: All 25 individuals were suspected of having a flare-up of the hip based on clinical history and a favorable response to a four day course of high-dose oral prednisone. Ten individuals (40%) experienced rebound symptoms of pain and/or stiffness within seven days after discontinuation of prednisone and all ten subsequently developed heterotopic ossification (HO) or decreased mobility of the affected hip. None of the 14 individuals who experienced sustained relief of symptoms following a course of oral prednisone experienced HO or decreased mobility. Incidental radiographic findings at the time of presentation were multifactoral and included osteochondromas of the proximal femur (18/25; 72%), degenerative arthritis (17/25; 68%), developmental hip dysplasia (15/25; 60%), previously existing heterotopic ossification (12/25; 48%), intra-articular synovial osteochondromatosis (8/25; 32%) or traumatic fractures through pre-existing heterotopic bone (1/25; 4%)., Conclusions: Developmental joint pathology may confound clinical evaluation of hip pain in FOP. The most useful modality for suspecting an ossification-prone flare-up of the hip was lack of sustained response to a brief course of oral prednisone. Evaluation of soft tissue edema by ultrasound or magnetic resonance imaging showed promise in identifying ossification-prone flare-ups and warrants further analysis in prospective studies., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare and devastating disorder characterized by cumulative episodes of progressive heterotopic ossification. It is estimated that there exist 600-700 patients in Mainland China. Nevertheless, due to the rarity, many FOP patients were initially misdiagnosed. Until now fewer than 150 patients have been identified in Mainland China. This review summarizes the epidemiology and clinical features of FOP patients, the progress of clinical and basic research in China, and the future of FOP care in China., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Fibrodysplasia ossificans progressiva is characterized by congenital skeletal anomalies and progressive heterotopic ossification. We present a 4 year old male patient who underwent unnecessary harmful multiple biopsies before the diagnosis of fibrodysplasia ossificans progressiva is made. Though rare, diagnosis of fibrodysplasia ossificans progressiva should be considered whenever characteristic radiographic features of multifocal heterotopic bone formation is seen along with the valgus deformities of the big toes.

Çakan M, Aktay-Ayaz N, Karadağ ŞG, Keskindemirci G. An extreme entity in differential diagnosis of musculoskeletal involvement-fibrodysplasia ossificans progressiva: a case based review. Turk J Pediatr 2018; 60: 593-597. Fibrodysplasia ossificans progressiva is one of the most devastating disorder of mankind characterized by progressive heterotopic ossification. Apart from hallux valgus, other symptoms start to develop in the first decade of life. The initial symptoms are tumefactive lesions on the back that gives an impression of benign or malignant tumoral lesion. It may cause restricted motion of the neck and shoulders and magnetic resonance imaging of the lesions may be reported as myositis or myofasciitis and these children may be referred to rheumatologists. Currently there is no definitive treatment of the disease but the most important issue in these patients is `primum non nocere`, because any invasive procedure could potentially trigger a flare and heterotopic calcification. Herein, we present a young case of fibrodysplasia ossificans progressiva to remind the typical signs and symptoms of the disease to all clinicians caring for children.

This case report describes the diagnosis, surgical treatment, and management of a patient with low-grade chondrosarcoma of the cervical spine that initially presented as myositis ossificans. Chondrosarcoma is rare in the cervical spine and in this patient, may have been the result of an injury from a motor vehicle crash. The management of this patient has been unusual in that a complete excision was not performed because the patient refused standard treatment.

We report a case of an 18-year-old woman, with bilateral acute inflammatory pain on the hip area, during the premenstrual period, and progressive increase in volume and rigidity of both hips. Bilateral exuberant soft tissue calcifications were present on the radiographic exams, and the patient also presented with bilateral short-length hallux valgus. A heterozygous mutation in the protein kinase domain of ACVR1 gene was found, allowing the diagnosis of fibrodysplasia ossificans progressive. Due to the relation between the disease flares and the premenstrual period, the patient was put into a chemically induced amenorrhea, with no new inflammatory crises since.This case illustrates the importance of an accurate diagnosis to prevent unnecessary diagnostic procedures, as well as the need to develop specific treatment strategies to address each patient's particular needs., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

We report a case of a 29-year-old man who had been a victim of a public road accident. Four weeks later, the patient developed an isolated right thigh mass located ventrally in the distal one-third of the thigh. The mass was painful and associated with fever and inflammatory syndrome. Plain radiographs showed a bilateral calcified thickening of soft tissues with well-defined bony margins. Ultrasound objectified diffuse calcifications of soft tissues.CT scan-confirmed the diagnosis of myositis ossificans circumscripta, showing a bilateral thickening of the vastus intermedius chief of the quadriceps dotted with calcifications, extending along the femur axis. These calcifications have well-defined bony margins separated from the periosteum by a lucent zone., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background: Congenital bilateral hallux valgus with associated absence or fusion of the interphalangeal joint is a classic diagnostic feature of fibrodysplasia ossificans progressiva (FOP), a human genetic disease of extra-skeletal bone formation caused in nearly all cases by a gain-of-function mutation in Activin A Receptor I/Activin-like Kinase 2 (ACVR1/ALK2), which encodes a bone morphogenetic protein (BMP) Type 1 receptor. This toe malformation prompts the suspicion of FOP even before the appearance of extra-skeletal bone. Here we report the case of a four-month-old child who was suspected of having FOP on the basis of a great toe malformation identical to that seen in children with the disease., Methods: The patient's genomic DNA of the coding region of ACVR1 was sequenced and analyzed for mutations known to cause FOP and novel mutations. Subsequent comparative genomic hybridization (CGH) and single nucleotide polymorphism (SNP) analyses were performed to detect mutations elsewhere in the genome., Results: Genetic testing exonerated ACVR1 as culpable for the patient's toe malformation. CGH and SNP analyses identified a large intragenic deletion in a different BMP Type 1 receptor gene, BMP Receptor 1B/Activin-like kinase 6 (BMPR1B/ALK6), a gene associated with a variable spectrum of autosomal dominant brachydactyly phenotypes., Conclusions: This report illustrates that while toe morphology remains the earliest indicator of FOP, toe morphology alone is not an unequivocal clinical diagnostic feature of FOP, and supports that embryonic development of the great toe is highly sensitive to dysregulated signaling from at least two BMP type I receptors., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Fibrodysplasia ossificans progressiva (FOP), a disabling disorder of progressive heterotopic ossification (HEO), is caused by heterozygous gain-of- function mutations in Activin receptor A, type I (ACVR1, also known as ALK2), a bone morphogenetic protein (BMP) type I receptor. Presently, symptomatic management is possible, but no definitive treatments are available. Although extensive guidelines for symptomatic management are widely used, regional preferences exist. In order to understand if there was worldwide consensus among clinicians treating FOP patients, an expert panel of physicians directly involved in FOP patient care was convened. Using a modified Delphi method, broad international consensus was reached on four main topics: diagnosis, prevention of flare-ups, patient and family-centered care and general clinical management issues. This study of physician preferences provides a basis for standardization of clinical management for FOP.

Fibrodysplasia ossificans progressiva (FOP) is a rare disease characterized by the association of congenital bone abnormalities and extraskeletal ossification flare-ups occurring in muscles and fasciae. Early diagnosis is important to prevent ossification flare-ups, but some atypical presentations can lead to errors in diagnosis and therefore delay. Here, we report on a case of an atypical presentation of FOP in a girl, in whom prominent transverse reductional abnormalities delayed diagnosis. The patient developed extraskeletal ossifications and progressive fibrosis that led to motor restrictions. Since early diagnosis is important, we discuss the clinical presentations of FOP and the differential diagnoses., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Background Myosits ossificans (MO) is a rare but important differential diagnosis for a heterotrophic bony tumor in the muscles. It is often misdiagnosed as a malignant tumor. With a previous trauma the diagnosis is myositis ossificans traumatic (MOT). In most cases, it is benign and predominantly seen in the big muscles. But there can be malignant etiologies too. Case Description We report a rare case of MO in the muscle of the craniocervical junction. This 37-year-old woman had a riding accident years ago. Because of persisting pain and cervical dysfunction, we did a total resection. Clinical Implications MOT is a benign tumor that can be treated conservative in most cases. In case of persistent pain or neurological deficits, and especially for securing diagnosis, surgical resection is recommended., Competing Interests: Interessenkonflikt: Nein., (Georg Thieme Verlag KG Stuttgart · New York.)

A 77-year-old male who had had an olecranon fracture 15 years ago presented himself with mild pain of the right elbow. Physical examination revealed painless hardening of the finger and wrist flexors in an area of 10 cm from the origin. Conventional radiographs showed a mature myositis ossificans.

Fibrodysplasia Ossificans Progressiva is a rare debilitating disorder of the musculoskeletal system affecting one in two million individuals. It is characterized by progressive extraskeletal ossification of soft tissues resulting in the original skeleton being encased in unyielding new bone leading to disability and ultimately death from cardiorespiratory failure. The present case brings to light the delays and potential pitfalls in diagnosis as a result of the rarity of the condition., Competing Interests: Conflict of interest: None declared

Myositis ossificans progressiva (MOP) is an autosomal dominant disorder. There is a progressive ectopic ossification and skeletal malformation, mainly in the connective tissue of muscle. The diagnosis is based on the clinical findings and radiological demonstration of the skeletal malformations. A 38-year-old female patient was admitted to our department with progressive increase of the thigh. Results of laboratory studies were normal. The radiography of the right thigh showed multiple intramuscular calcifications. Myositis ossificans progressiva should be diagnosed as early as possible and non-invasively, based upon history, clinical and radiological findings. Early and correct diagnosis is fundamental for indication of proper management of the disease., Competing Interests: The authors declare no conflict of interest.

Myositis ossificans circumscripta (MOC) is a rare condition characterized by nontumoral heterotopic ossification of the soft tissues. This condition affects young subjects, occurring mainly after trauma. It is ubiquitous, predominantly located in girdles and limbs. We report the case of a young patient with paravertebral MOC without traumatic context; the aim of this study was to recall diagnostic criteria and imaging aspects.

Background: Myositis Ossificans Cicumscripta is a rare condition characterized by aberrant bone formation in paramuscular soft tissue of the extremities usually associated with trauma or a genetic mutation. Very few cases involve the head or neck and it is rarely found in the pediatric population., Objectives: We present a case of a 5-month old with a rapidly growing posterior neck mass suspicious for neoplasia, which was treated with surgical resection and found to be a non-traumatic, non-genetic form of Myositis Ossificans. The workup, treatment, and findings of the patient are outlined and a review of the literature on this disease is discussed., Conclusion: Myositis Ossificans is characterized by aberrant bone formation typically occurring after trauma but may be secondary to an underlying genetic abnormality. The case presented in the absence of trauma or an underlying genetic abnormality and is therefore an exceedingly rare instance of the sporadic form that presented spontaneously in the head and neck of a pediatric patient., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Fibrodysplasia ossificans progressiva is a rare disorder of heterotopic ossification. Procedures like biopsy and surgery are known to be aggravating factors in promoting heterotopic ossification Clues to clinical diagnosis may therefore be a great advantage to treating orthopedician. Valgus deformity of great toe is an important diagnostic clue for treating physicians and thus aids in preventing the clinicians from subjecting the patients to unnecessary invasive and traumatic procedures. Hence clinical clues to early diagnosis are important in establishing the correct diagnosis and directing future management.

Fibrodysplasia ossificans progressiva is a rare autosomal dominantly inherited disorder of connective tissue caused by mutations in the gene encoding for ACVR1/ALK2, a bone morphogenetic protein type I receptor. It is mainly characterized by congenital malformations of the great toes and the formation of qualitatively normal bone in extra-skeletal sites leading to severe disability and eventually death. We present a sporadic case from Northern Tanzania with a minor unilateral hallux anomaly and the common ACVR1 c.617G>A mutation.

Severe variants of fibrodysplasia ossificans progressiva (FOP) affect <2% of all FOP patients worldwide, but provide an unprecedented opportunity to probe the phenotype-genotype relationships that propel the pathology of this disabling disease. We evaluated two unrelated children who had severe reduction deficits of the hands and feet with absence of nails, progressive heterotopic ossification, hypoplasia of the brain stem, motor and cognitive developmental delays, facial dysmorphology, small malformed teeth, and abnormal hair development. One child had sensorineural hearing loss, microcytic anemia, and a tethered spinal cord and the other had a patent ductus arteriosus and gonadal dysgenesis with sex reversal (karyotype 46, XY female). Both children had an identical mutation in ACVR1 c.772A>G; p.Arg258Gly (R258G), not previously described in FOP. Although many, if not most, FOP mutations directly perturb the structure of the GS regulatory subdomain and presumably the adjacent αC helix, substitution with glycine at R258 may directly alter the position of the helix in the kinase domain, eliminating a key aspect of the autoinhibitory mechanism intrinsic to the wild-type ACVR1 kinase. The high fidelity phenotype-genotype relationship in these unrelated children with the most severe FOP phenotype reported to date suggests that the shared features are due to the dysregulated activity of the mutant kinase during development and postnatally, and provides vital insight into the structural biology and function of ACVR1 as well as the design of small molecule inhibitors., (© 2015 Wiley Periodicals, Inc.)

Myositis ossificans (MO) is a rare benign cause of heterotopic bone formation in soft tissue that most commonly affects young adults, typically following trauma. We report the case of an 11-year-old girl who developed MO mimicking osteosarcoma in her right shoulder. Plain radiography and computed tomography showed poorly defined flocculated densities in the soft tissue and a periosteal reaction along the proximal humerus. On magnetic resonance imaging, the mass displayed an ill-defined margin and inhomogeneous signal change. Histologically, the mass had a pseudosarcomatous appearance. Based on these findings, the patient was initially misdiagnosed with osteosarcoma at another hospital. The diagnosis was difficult because the patient was 11 years old and had no trauma history, with atypical radiographic changes and a predilection for the site of origin for osteosarcomas. We finally made the correct diagnosis of MO by carefully reviewing and reflecting on the pathological differences between stages., (© 2015 Japan Pediatric Society.)

Myositis ossificans is a self-limiting, benign ossifying lesion that can affect any type of soft tissue, including subcutaneous fat, tendons, and nerves. It is most commonly found in muscle as a solitary lesion. Ossifying soft-tissue lesions historically have been inconsistently classified. Fundamentally, myositis ossificans can be categorized into nonhereditary and hereditary types, with the latter being a distinct entity with a separate pathophysiology and treatment approach. The etiology of myositis ossificans is variable; however, clinical presentation generally is characterized by an ossifying soft-tissue mass. Advanced cross-sectional imaging alone can be nonspecific and may appear to be similar to more sinister etiologies. Therefore, the evaluation of a suspicious soft-tissue mass often necessitates multiple imaging modalities for accurate diagnosis. When imaging is indeterminate, biopsy may be required for a histologic diagnosis. However, histopathology varies based on stage of evolution. The treatment of myositis ossificans is complex and is often made in a multidisciplinary fashion because accurate diagnosis is fundamental to a successful outcome., (Copyright 2015 by the American Academy of Orthopaedic Surgeons.)

Soft tissue lesions can contain bone or cartilage matrix as an incidental, often metaplastic, phenomenon or as a diagnostic feature. The latter category includes a diverse group ranging from self-limited proliferations to benign neoplasms to aggressive malignancies. Correlating imaging findings with pathology is mandatory to confirm that a tumor producing bone or cartilage, in fact, originates from soft tissue rather than from the skeleton. The distinction can have dramatic diagnostic and therapeutic implications. This content focuses on the gross, histologic, radiographic, and clinical features of bone or cartilage-producing soft tissue lesions. Recent discoveries regarding tumor-specific genetics are discussed., (Copyright © 2015 Elsevier Inc. All rights reserved.)

A young soccer player was diagnosed with myositis ossificans 6 weeks after a muscle strain in the right thigh. Radiographic and sonographic investigations initially helped to confirm diagnosis and later supported clinical improvement. We present our approach to the case and discuss pathophysiology, prevention and treatment of this rare condition., (2015 BMJ Publishing Group Ltd.)

Fibrodysplasia ossificans progressiva is a rare genetic disease that manifests in early life with malformed big toes and progressive heterotopic ossification that forms qualitatively normal bone in characteristic extraskeletal sites. Mutation c.617G>A in the activin A receptor type I gene is reported in all patients with fibrodysplasia ossificans progressiva. No cases of cardiac involvement have been described in children. We report the case of a child with halluces valgi at birth, along with two tender, firm, immovable masses located on the right and left parietal-occipital region, a transitory subluxation of the right hip and an unusual ventricular septal hypertrophy. We hypothesize that the ventricular septal hypertrophy could be the result of a thickening of the fibrous portion of the septum, and a possible new element of the phenotype, probably resulting from the mechanical stimuli secondary to the significant hemodynamic changes occurring at birth., (© 2015 Japan Pediatric Society.)

An 18-year-old man presented with mid left thigh pain after sequential lacrosse injuries 1 month and 2 weeks prior. Physical examination was significant for a tender mass in the mid left thigh., (Copyright 2015, SLACK Incorporated.)