Proliferative Myositis Research Articles

Proliferative Myositis in the Upper Extremity: Vaccination-Induced Pathology?

Proliferative myositis (PM) is a rare type of inflammatory myositis. It is a benign and self-limiting pathology, but its clinical presentation can simulate malignancy. This pictorial essay illustrates the typical imaging findings of PM on ultrasound (US) and magnetic resonance imaging (MRI) in three patients. Clinical history in all three patients revealed recent vaccination procedures.

Proliferative Myositis of the Erector Spinae Mistaken for Malignancy

We report the case of a 56-year-old woman who presented with a enlarging, painful upper back mass that had developed 4 days ago. The patient was referred to the Emergency Department from a primary care facility after ultrasonography showed an ill-defined mass-like lesion in the back muscle with potential for malignancy. Magnetic resonance imaging and ultrasonography at Eunpyeong St.Mary’s Hospital revealed an ill-defined hypervascular lesion longitudinally oriented in the left erector spinae. The initial differential diagnosis included an inflammatory mass such as proliferative myositis, sarcoidosis, low-grade lymphoma and low-grade infection. The patient underwent ultrasound-guided biopsy with pathology confirming proliferative myositis. Proliferative myositis is a rare benign proliferation of the skeletal muscles that can be mistaken for a malignancy due to its rapid progression.

Lack of FOS/FOSB Gene Rearrangements in Ischemic Fasciitis Indicates Distinct Pathogenesis from Proliferative Fasciitis and Proliferative Myositis.

Ischemic fasciitis is a pseudosarcomatous fibroblastic/myofibroblastic proliferation that shares several overlapping morphological features with proliferative fasciitis and proliferative myositis. Prompted by a recent study that demonstrated FOS gene rearrangements in proliferative fasciitis and proliferative myositis, suggesting that these lesions likely represent examples of "transient neoplasia," we examined a cohort of ischemic fasciitis for similar events. Nine cases of ischemic fasciitis were retrieved from our institutional archives for diagnosis verification, immunostaining for FOSB, and fluorescence in situ hybridization using validated FOS and FOSB break-apart probes. Additionally, RNAseq was performed on a subset of cases. In our cohort, eight out of nine cases of ischemic fasciitis were positive for FOSB IHC, but FISH studies were consistently negative for FOSB and FOS gene rearrangements in all cases. Additionally, RNA sequencing did not detect any gene fusions. These findings suggest that the pathogenesis of ischemic fasciitis is distinct from that of proliferative fasciitis and proliferative myositis.

The web-like pattern on MRI of proliferative myositis.

The web-like pattern on MRI of proliferative myositis.

Utility of C-FOS immunohistochemistry as an ancillary tool in the diagnosis of proliferative fasciitis and proliferative myositis

Introduction: Proliferative fasciitis (PF) and proliferative myositis (PM) are benign soft tissue neoplasms occurring in the subcutaneous tissue (PF) or skeletal muscle (PM).1 Gene FOS rearrangements and immunohistochemical (IHC) expression have been recently identified in PF/PM in a single study.2

Sarcomatoid Lesions of Head and Neck Region: A Diagnostic Dilemma

One challenging feature of head and neck pathology is that a dizzying array of sarcomatoid lesions occurs here ranging all the way from reactive to malignant and very aggressive. This makes accurate diagnosis critical. These lesions are quite diverse with great clinical and biological heterogeneity. Some are malignant while many others are benign or simply reactive in nature. For example; at mucosal sites, a well known lesion is spindle cell carcinoma (SpCC), which are overtly malignant, and the differential diagnosis then includes a number of different malignant spindle cell lesions. However, there are several benign or even non-neoplastic lesions that can sometimes be difficult to discern from SpCC, e.g. Nodular fasciitis, Proliferative myositis, Cellular schwannoma, Benign fibrous histiocytoma, Carcino sarcoma, Sarcomatoid melanoma. Fracture callus, etc.
 Aim of Study: There is a diagnostic challenge to the oral pathologists to differentiate dizzying array of sarcoma like lesions from other similar microscopic simulates ranging all the way from reactive to malignant and very aggressive. This article aims to review the sarcomatoid lesions of the head and neck region with emphasis on differential diagnosis histologically and immunohistochemicaly.

Proliferative fasciitis, a rare pseudosarcoma

Of the many benign mimickers of soft tissue sarcoma, proliferative fasciitis is a rare entity which is a diagnostic challenge for pathologist. Recognition of this pseudo sarcoma is very essential as it aids in the appropriate management of the same. Other members of the pseudo sarcoma family are proliferative myositis, nodular fasciitis, inflammatory pseudotumor and proliferative peribursitis. We present 3 cases of proliferative fasciitis which was reported in our hospital in the last 10 years, between 2007 and 2017. Keywords: Pseudosarcoma, Proliferative fasciitis, Rare soft tissue pseudo sarcoma.

Recurrent FOS rearrangement in proliferative fasciitis/proliferative myositis.

Proliferative fasciitis (PF) and proliferative myositis (PM) are rare benign soft tissue lesions, usually affecting the extremities of middle-aged or older adults. Presenting as poorly circumscribed masses, they histologically show bland spindle cell proliferation in a myxoid to fibrous background and a hallmark component of large epithelioid "ganglion-like" cells in various numbers, which may lead to their misdiagnosis as sarcoma. PF/PM has been long considered as reactive, akin to nodular fasciitis; however, its pathogenesis has remained unknown. In this study, we analyzed the FOS status in 6 PF/PMs (5 PFs and 1 PM). Five PF/PMs occurred in adults, all showing diffuse strong expression of c-FOS primarily in the epithelioid cells, whereas spindle cell components were largely negative. Using fluorescence in situ hybridization (FISH), all 5 c-FOS-immunopositive tumors showed evidence of FOS gene rearrangement in the epithelioid cells. RNA sequencing in 1 case detected a FOS-VIM fusion transcript, which was subsequently validated by reverse transcriptase-polymerase chain reaction, Sanger sequencing, and VIM FISH. The one pediatric PF case lacked c-FOS expression and FOS rearrangement. c-FOS immunohistochemistry was negative in 45 cases of selected mesenchymal tumor types with epithelioid components that may histologically mimic PF/PM, including pleomorphic sarcoma with epithelioid features and epithelioid sarcoma. Recurrent FOS rearrangement and c-FOS overexpression in PF/PM suggested these lesions to be neoplastic. FOS abnormality was largely restricted to the epithelioid cell population, clarifying the histological composition of at least 2 different cell types. c-FOS immunohistochemistry may serve as a useful adjunct to accurately distinguish PF/PM from mimics.

A Case of Proliferative Myositis Arising from the Sternocleidomastoid Muscles: Diagnosis and Treatment

We describe here diagnosis treatment of a case that rose from the sternocleidomastoid muscle and was treated without surgical excision. A 56-year-old man presented with a rapidly growing, painless and not well-circumscribed mass at the right side of the neck. We diagnosed this tumor as proliferative myositis (PM) based on the typical findings from ultrasonography, computed tomography, and core-needle biopsy, and treated it without surgical excision. Herein we report a successful diagnosis and treatment process of a case of PM, which was followed-up with ultrasonography.

Preoperative Diagnosis of Proliferative Myositis by Enhanced Computed Tomography and the Apparent Diffuse Coefficient Map from Magnetic Resonance Imaging

Proliferative myositis is a rare intramuscular inflammatory lesion that occurs in the head and neck and which could be resolved without treatment. Herein, we present the imaging characteristics for its preoperative diagnosis, potentially mitigating the need for surgery. We describe the enhanced computed tomography (CT) and magnetic resonance imaging (MRI) findings of two patients. We observed a checkerboard-like pattern in the sternocleidomastoid muscle on enhanced CT in one patient. We also identified the involvement of two heads of the sternocleidomastoid muscle. Coronal enhanced CT imaging was also useful in the preoperative diagnosis because it revealed a lattice structure, equivalent to muscle fibers. On MRI, diffusion-weighted sequences showed hyperintensity, and the apparent diffusion coefficient map showed hypointensity in proliferative myositis. Enhanced CT and MRI-based diffusion-weighted sequences and the apparent diffusion coefficient map are useful in the preoperative diagnosis of proliferative myositis and could be useful for avoiding the need for complete surgical excision.

Proliferative Myositis: A Comprehensive Review of 33 Case Reports

Proliferative myositis, a rare reactive intramuscular myofibroblastic proliferation, is not well recognized in clinical practice. It overgrows within a few weeks and expands the space between the muscle causing infiltrative-like border mimicking sarcoma. Knowledge of the natural history and pathology of proliferative myositis is essential in order to prevent misdiagnosis and unnecessary surgical resection. Thirty-three reported cases of proliferative myositis in PubMed and Web of Science databases from 2000 to 2018 had been reviewed with the main emphasis in clinical presentation, radiological and pathological findings, treatment, and prognosis. Both males (19 cases) and females (14 cases), predominantly the middle-aged and senior adults, were affected. Upper extremity and shoulder girdle were commonly involved. The chief complaint varied from either painful or painless mass. The traumatic injury was reported as a significant predisposing factor. The lesion typically proliferated and separated muscle bundle. Ultrasonography of the lesion revealed a characteristic “checkerboard pattern” on transverse view. The definite diagnosis was based on the demonstration of spindle-shaped fibroblast/myofibroblast admixed with giant ganglion-like cells in the biopsy. Immunohistochemistry may be useful diagnostic tool when the histopathology was inconclusive. Misdiagnosis of sarcoma occurred due to its rapid growth and infiltrative-like border. Watchful management without surgery was sufficient because of the potential for spontaneous regression. Thoroughly clinical examination and appropriate investigations, including imaging and histopathology, are crucial.

Proliferative myositis

We report on a 42-year-old woman showing a rapidly growing tumor on her left flank; it was removed by surgery. Histological examination revealed the typical picture of proliferative myositis. Since the clinical symptoms of this disease are nonspecific, the diagnosis always depends on histological evidence. Despite its rapid growth and its cellular pleomorphism, proliferative myositis is a reactive process and has to be differentiated histologically from sarcoma of the soft tissue.

What do we know about intravascular fasciitis affecting inferior vena cava? management and report of a case

Intravascular fasciitis is a rare entity characterized by the proliferation of myofibroblasts and giant cells in relation to small and medium-sized blood vessels. It characterized by a rapid growth and its morphology can simulate other malignant neoplastic processes of more aggressive behavior such as sarcomas. It belongs to a group of benign lesions that affect the subcutaneous tissue and fascia (sometimes to the muscle) sharing characteristics similar to proliferative fasciitis, nodular fasciitis and proliferative myositis. It can sometimes be confused with lesions typical of fibromatosis even. We report a case of a patient with a symptomatic retroperitoneal mass who underwent surgery. The intraoperative findings showed a tumor originating in the inferior vena cava. The histopathological study revealed an intravascular fasciitis.

Proliferative myositis in the right brachioradialis: A case report.

Proliferative myositis is a rare, self-limiting, benign disease. Its diagnosis can be difficult and in many cases is not confirmed until after surgical resection. Herein, we report a case of proliferative myositis of the right brachioradialis in a 64-year-old man. The patient presented with a rapidly growing, painless mass in his right forearm. Magnetic resonance imaging and fine-needle aspiration biopsy led to a diagnosis of proliferative myositis. Complete surgical resection of the mass was performed. Postoperative pathological examination confirmed the diagnosis. To the best of our knowledge, this is the first report of proliferative myositis in the right brachioradialis. Fine-needle biopsy is helpful in the diagnosis of proliferative myositis, thus avoiding unnecessary surgical trauma and costs.

Perirectal Proliferative Myositis: A Case Report

Proliferative myositis is a rapidly growing benign intramuscular proliferative lesion that is believed to be incited by muscle trauma; these lesions are managed by either surgical excision or watchful waiting, as they have shown a tendency for spontaneous regression. The patient is a …

Miositis proliferativa con metaplasia ósea. Reporte de un caso

Proliferative myositis is a rare, benign lesion and the presence of osseous metaplasia is even more infrequent. Its rapid growth and diffuse infiltration pattern may cause it to be confused with a malignant tumour. We present a case of proliferative myositis in a 68 year old male with a history of low grade fibromyxiod sarcoma who presented with swelling in the anterior left shoulder.An ill-defined, 2×1cm whitish lesion was found in the deltoid muscle. A proliferation of spindle cells, pseudoganglion cells and calcified osteoid was observed. Immunohistochemistry showed positivity for vimentin, β-catenin (cytoplasmic), Ki 67 (6%) and focal positivity for actin and myosin smooth muscle in spindle cells, negativity for MYO-D1, myogenin, CD34, desmin, caldesmon. A diagnosis of proliferative myositis with foci of osseous metaplasia was made.

Proliferative Myositis: A Rare Pseudosarcoma in Children

Proliferative myositis is one of several benign, rapidly enlarging tumours of soft tissue that are often confused with sarcoma. We present an unusual case of proliferative myositis in a 7 year female involving right submandibular region. Proliferative myositis is a rare, inflammatory tumour that is often misdiagnosed as sarcoma. The clinical course of proliferative myositis is benign, and simple excision is curative.

FNAC Diagnosis of Soft Tissue Tumour (Proliferative Fascitis and Proliferative Myositis ): A Case Report

Nodular fascitis is a benign fibroblastic tumour characterized by rapid growth and most of the time requires its differentiation from other tumorous lesions. Here is a case of 45 year old male who presented with a soft tissue swelling in the popliteal region. On FNAC, a differential diagnosis of proliferative myositis and proliferative fasciitis was given. Histopathological examination gave a diagnosis of nodular fascitis. Hence cytology helps to give a definite diagnosis and aid in the surgical management of soft tissue tumors.

Benign proliferative myositis of the sternohyoid muscle: Review and case report

We report a case of a 51-year-old woman who presented with a rapidly enlarging, painful, midline neck mass that developed over a three day period. A CT scan of the neck showed a solid circumscribed mass in the sternohyoid muscle. The initial differential diagnosis included inflammation of thyroglossal duct remnant, an abnormal lymph node, and thyroid carcinoma. The patient underwent operative excision with final pathology revealing proliferative myositis. Proliferative myositis is an uncommon benign proliferation of skeletal muscle and has only been reported a limited number of times in the head and neck region.

Atypical proliferative myositis: original MR description with pathologic correlation: Case report

Proliferative myositis (PM) along with proliferative fasciitis and nodular fasciitis are a group of pseudosarcomatous myofibroblastic proliferations. Although the histologic presentation of each is almost identical, the magnetic resonance imaging (MRI) appearance of proliferative myositis is closer to that of inflammatory myopathies. We report a case of PM in which the imaging and histologic features combine typical findings of PM with unusual imaging features, suggesting of reactive (or nodular) fasciitis.