Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disease that is characterized by the formation of heterotopic bone tissues in soft tissues, such as skeletal muscle, ligament, and tendon. It is difficult to remove such heterotopic bones via internal medicine or invasive procedures. The identification of activin A receptor, type I (ACVR1)/ALK2 gene mutations associated with FOP has allowed the genetic diagnosis of FOP. The ACVR1/ALK2 gene encodes the ALK2 protein, which is a transmembrane kinase receptor in the transforming growth factor-β family. The relevant mutations activate intracellular signaling in vitro and induce heterotopic bone formation in vivo. Activin A is a potential ligand that activates mutant ALK2 but not wild-type ALK2. Various types of small chemical and biological inhibitors of ALK2 signaling have been developed to establish treatments for FOP. Some of these are in clinical trials in patients with FOP.
Activins ; Bone and Bones ; Diagnosis ; Humans ; In Vitro Techniques ; Internal Medicine ; Ligaments ; Muscle, Skeletal ; Myositis Ossificans* ; Osteogenesis ; Phosphotransferases ; Tendons ; Transforming Growth Factor beta

A calcification mass was incidentally found in the soft tissue of a patient who had a history of trauma to the extremity during examination. The patient had no symptom. The pathological analysis of the mass revealed it was an early-phase synovial sarcoma (SS). The diagnosis was made before the onset of symptoms and proper surgical intervention was performed. Therefore, in case of a <1 cm lesion clinically suspicious of myositis ossificans, SS should be taken into consideration as a possible diagnosis.
Diagnosis ; Extremities ; Femur ; Humans ; Myositis Ossificans ; Myositis ; Sarcoma, Synovial

Myositis ossificans (MO) is a benign condition of non-neoplastic heterotopic bone formation in the muscle or soft tissue. Trauma plays a role in the development of MO, thus, non-traumatic MO is very rare. Although MO may occur anywhere in the body, it is rarely seen in the lumbosacral paravertebral muscle (PVM). Herein, we report a case of non-traumatic MO in the lumbosacral PVM. A 42-year-old man with no history of trauma was referred to our hospital for pain in the low back, left buttock, and left thigh. On physical examination, a slightly tender, hard, and fixed mass was palpated in the left lumbosacral PVM. Computed tomography showed a calcified mass within the left lumbosacral PVM. Magnetic resonance imaging (MRI) showed heterogeneous high signal intensity in T1- and T2-weighted image, and no enhancement of the mass was found in the postcontrast T1-weighted MRI. The lack of typical imaging features required an open biopsy, and MO was confirmed. MO should be considered in the differential diagnosis when the imaging findings show a mass involving PVM. When it is difficult to distinguish MO from soft tissue or bone malignancy by radiology, it is necessary to perform a biopsy to confirm the diagnosis.
Biopsy ; Buttocks ; Diagnosis, Differential ; Magnetic Resonance Imaging ; Muscles ; Myositis ; Myositis Ossificans ; Osteogenesis ; Physical Examination ; Thigh

12E7 Antigen ; Aged ; Antigens, CD ; metabolism ; Cell Adhesion Molecules ; metabolism ; Diagnosis, Differential ; Giant Cell Tumors ; pathology ; Giant Cells ; pathology ; Humans ; Male ; Mesenchymoma ; pathology ; Mucin-1 ; metabolism ; Myositis Ossificans ; pathology ; Osteosarcoma ; metabolism ; pathology ; surgery ; Penile Neoplasms ; metabolism ; pathology ; surgery ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Vimentin ; metabolism

Trigger point injection is a simple procedure that is widely performed for relieving pain. Even though there are several complications of trigger point injection, myositis ossificans has not been documented as one of its complications. We treated a patient who suffered from painful limitation of elbow motion and this was caused by myositis ossificans between the insertions of brachialis and supinator muscles after a trigger point injection containing lidocaine mixed with saline, and we also review the relevant medical literature.
Adult ; Elbow/surgery ; Humans ; Injections, Intralesional/*adverse effects ; Lidocaine/*adverse effects/therapeutic use ; Magnetic Resonance Imaging ; Male ; Myofascial Pain Syndromes/drug therapy ; Myositis Ossificans/diagnosis/*etiology/radiotherapy/surgery ; Range of Motion, Articular

Fibrodysplasia ossificans progressiva (FOP; OMIM 135100) is a rare but extremely disabling genetic disorder of the skeletal system, and is characterized by the progressive development of ectopic ossification of skeletal muscles and subsequent joint ankylosis. The c.617G>A; p.R206H point mutation in the activin A type I receptor (ACVR1) gene has been reported to be a causative mutation of FOP. In the present study, mutation analysis of the ACVR1 gene was performed in 12 patients diagnosed or suspected to have FOP. All patients tested had a de novo heterozygous point mutation of c.617G>A; p.R206H in ACVR1. Mutation analysis confirmed a diagnosis of FOP in patients with ambiguous features, and thus, could be used for diagnostic purposes. Early confirmation through mutation analysis would allow medical professionals to advise on the avoidance of provoking events to delay catastrophic flare-ups of ectopic ossifications.
Activin Receptors, Type I/*genetics ; Adolescent ; Adult ; Asian Continental Ancestry Group/*genetics ; Base Sequence ; Child ; Female ; Genetic Predisposition to Disease ; Heterozygote ; Humans ; Korea ; Male ; Myositis Ossificans/*diagnosis/genetics/radiography ; Point Mutation ; Young Adult

Fibrodysplasia ossificans progressiva (FOP; OMIM 135100) is a rare but extremely disabling genetic disorder of the skeletal system, and is characterized by the progressive development of ectopic ossification of skeletal muscles and subsequent joint ankylosis. The c.617G>A; p.R206H point mutation in the activin A type I receptor (ACVR1) gene has been reported to be a causative mutation of FOP. In the present study, mutation analysis of the ACVR1 gene was performed in 12 patients diagnosed or suspected to have FOP. All patients tested had a de novo heterozygous point mutation of c.617G>A; p.R206H in ACVR1. Mutation analysis confirmed a diagnosis of FOP in patients with ambiguous features, and thus, could be used for diagnostic purposes. Early confirmation through mutation analysis would allow medical professionals to advise on the avoidance of provoking events to delay catastrophic flare-ups of ectopic ossifications.
Activin Receptors, Type I/*genetics ; Adolescent ; Adult ; Asian Continental Ancestry Group/*genetics ; Base Sequence ; Child ; Female ; Genetic Predisposition to Disease ; Heterozygote ; Humans ; Korea ; Male ; Myositis Ossificans/*diagnosis/genetics/radiography ; Point Mutation ; Young Adult

OBJECTIVETo study the clinicopathologic features, diagnosis and differential diagnosis of myositis ossificans (MO).

METHODSThe clinical features, radiologic results and pathologic findings of 15 cases of MO (including biopsy and surgical specimens) were analyzed. The hematoxylin and eosin sections were reviewed under light microscope. Immunohistochemical staining for S-100 protein, vimentin, desmin, actin and osteonectin was performed.

RESULTSThe age of the patients ranged from 12 to 46 years. The male-to-female ratio was 11:4. Thirteen cases were located in the parosteum of long bone or subperiosteal soft tissue. The remaining two cases occurred in iliac region and palm, respectively. Five patients had history of injury, while 2 patients had operation before. Four patients had no history of trauma and the remaining one had unknown clinical history. Histologically, zonation pattern was not conspicuous in 10 biopsy cases and 8 corresponding surgical specimens. On the other hand, zonation pattern was observed in 5 biopsy cases and 7 corresponding surgical specimens. Follow up revealed relapses in two patients. Immunohistochemical study showed various degree of positivity for vimentin, desmin, actin and osteonectin. S-100 protein was focally positive in 2 of the cases. The Ki-67 index varied from 1% to 10%.

CONCLUSIONCorrect diagnosis of MO relies on correlation of clinical features, radiologic examination and pathologic findings.

Adolescent ; Adult ; Biopsy ; Child ; Female ; Humans ; Male ; Middle Aged ; Myositis Ossificans ; diagnosis ; genetics ; pathology ; S100 Proteins ; genetics ; Vimentin ; X-Rays ; Young Adult

Child, Preschool ; Diagnosis, Differential ; Humans ; Male ; Myositis Ossificans ; diagnosis ; diagnostic imaging ; pathology ; physiopathology ; Prognosis ; Tomography, X-Ray Computed

Osteochondromas are common and typically arise from the metaphyseal ends of long bones. An osteochondral neoplasm of the soft tissue, which is a lesion of uncertain pathogenesis, is uncommon and usually arises from the synovial tissue in joints and tendon sheaths. Rarely, extraskeletal osteochondromas also arise outside of synovial compartments. Most of the reported cases were presented in the hands and feet, especially in the fingers. Here we describe a 44-yr-old female patient who presented with a pain in the left buttock. A well-defined osseous mass was detected in the buttock. It consisted of sharply demarcated, mature hyaline cartilage that was covered with a fibrous capsule, which changed gradually into cancellous bone, more pronouncedly at the center. The diagnosis of an extraskeletal osteochondroma should be considered when a discrete, ossified mass is localized in the soft tissues. A case of pathologically proven extraskeletal osteochondroma of the buttock is presented with a literature review, magnetic resonance imaging, and radiological findings.
Accidental Falls ; Adult ; Buttocks* ; Diagnosis, Differential ; Female ; Human ; Myositis Ossificans/diagnosis ; Osteochondroma/complications ; Osteochondroma/diagnosis* ; Osteochondroma/radiography ; Osteochondroma/surgery ; Pain/etiology ; Sarcoma/diagnosis ; Soft Tissue Neoplasms/complications ; Soft Tissue Neoplasms/diagnosis* ; Soft Tissue Neoplasms/radiography ; Soft Tissue Neoplasms/surgery