Myopericytoma/myofibroma as a stromal component of mixed epithelial and stromal tumor of the kidney: A case report.

Mixed epithelial and stromal tumors (MESTs) of the kidney are rare renal neoplasms, primarily affecting middle-aged women. These tumors are characterized by a mix of epithelial and stromal components. While generally benign, MESTs require accurate diagnosis and appropriate management due to the potential for malignant transformation. The present study reports the case of a 75-year-old male patient who underwent a partial nephrectomy following the incidental discovery of a kidney tumor. Histopathological examination revealed a partially cystic tumor with solid areas, measuring 26 mm in diameter. The tumor had cysts lined with cuboidal cells and an ovarian-like stroma. The solid component consisted of elongated cells with eosinophilic cytoplasm and oval nuclei, showing angiocentric growth around small blood vessels without nuclear atypia or mitoses. Since the morphology of the solid component could not reveal the differentiation of those cells, immunohistochemical staining was performed and a myopericytoma/myofibroma component was established, mostly based on the positivity of smooth muscle actin, muscle-specific actin, h-caldesmon, estrogen receptor, progesterone receptor, solute carrier family 2 facilitated glucose transporter member 1 and collagen IV, along with a lack of staining for desmin, CD34, CD31 and CD99. Thus, to the best of our knowledge, for the first time in the literature, MEST with myopericytoma/myofibroma stromal component in a male patient was reported.

A rare case of cervical myofibroma in an infant: A case report.

INTRODUCTION: A solitary infantile myofibroma tumor arises as a hard, painless cutaneous or subcutaneous nodule and is defined as an uncommon soft tissue neoplasm that is usually seen in childhood. CASE PRESENTATION: A nine-month-old female infant presented with a solid mass that appeared one month ago. The mass gradually increased in size within the right posterior triangle of the neck, without any local or systemic accompanying symptoms. Laboratory tests were normal. Ultrasonography revealed a homogeneous tissue mass measuring 1.5 × 3 cm, with blood flow within it. Multislice CT scan accurately localized the isolated tumor. The mass was surgically excised and found within the sternocleidomastoid muscle, without any adhesions to adjacent tissues. Histological examination of the tumor and immunohistochemical tests confirmed infantile myofibroma. CLINICAL DISCUSSION: IM is one of the most common soft tissue tumors in children and mainly consists of myofibroblasts. 90 % of IM cases are diagnosed before the age of two years. Possible therapeutic measures for this tumor include conservative management, surgical resection, chemotherapy, radiation therapy, and steroid injections into the tumor. Surgical removal of the tumor is often performed, and if it is single and completely removed, the prognosis is good with a recurrence rate of less than 10 %. CONCLUSION: Infantile myofibroma is considered a benign tumor, but it may be fatal in some cases. Each case is treated individually according to the number (single or multicentric), size, location, symptoms, and visceral involvement. Surgical resection remains the therapeutic procedure of choice in most cases.

Clinicopathological features of myofibromas and myofibromatosis affecting the oral and maxillofacial region: A systematic review.

BACKGROUND: Myofibromas are rare benign neoplasms composed of myoid cells and myofibroblasts. This study aimed to systematically review case reports and a series of myofibromas (MF) and myofibromatosis (MFT) occurring in the oral and maxillofacial regions in order to describe their main clinicopathological features. METHODS: This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Electronic searches were conducted in 2023 in four databases: MEDLINE/PubMed, Web of Science, Scopus, and EMBASE. A manual search and a search in the grey literature were also conducted. The lesions were classified as MF or MFT according to their original report. RESULTS: A total of 169 cases were included in this systematic review. Men were slightly more affected, with a painless nodule. When occurring in soft tissue, MF usually developed in the gingiva (mean age:29.23 ± 21.93 years) and when it was intra-osseous, it occurred more frequently in the posterior mandible (mean age:14.33 ± 15.62 years). MFT occurred mainly in the mandible and was predominantly described as well-circumscribed masses of spindle cells organized in fascicles with a prominent vascular activity in a hemangiopericytoma-like pattern. The lesions were mainly positive for smooth muscle actin and vimentin immunomarkers. Surgical excision was the treatment of choice in the majority of cases and recurrence was observed in only three cases. CONCLUSION: MF and MFT affect more men, with an indolent clinical course. Intra-osseous tumors and MFT seem to occur more frequently in younger individuals. These lesions seem to have a good prognosis and low recurrence.

Myofibroma of the pinna: a case report and review of the literature.

BACKGROUND: Myofibromas are rare mesenchymal tumors with a predilection for the head, neck, and oral cavity. Primarily affecting infants and young children, these tumors typically manifest as superficial painless nodules. Diagnosis is confirmed through histopathological examination of a biopsy, revealing nodules characterized by spindle cell proliferation. To our knowledge, only two cases of pinna myofibroma have been previously reported in the literature. CASE PRESENTATION: Here, we present the case of a three-year-old male who developed a myofibroma of the left auricle following trauma to the area one year earlier. The patient underwent surgical resection without any postoperative complications. The patient later returned with a lesion consistent with hypertrophic scar. CONCLUSIONS: This study aims to provide a comprehensive review of the clinical presentation, histopathologic and immunohistochemical features, and surgical management of this unique case of myofibroma of the pinna.

Misdiagnosis of synovial sarcoma - cellular myofibroma with SRF-RELA gene fusion: A case report.

BACKGROUND: Cellular myofibroma is a rare subtype of myofibroma that was first described in 2017. Its diagnosis is often challenging because of its relative rarity, lack of known genetic abnormalities, and expression of muscle markers that can be confused with sarcomas that have myogenic differentiation. Currently, scholars have limited knowledge of this disease, and published cases are few. Further accumulation of diagnostic and treatment experiences is required. CASE SUMMARY: A 16-year-old girl experienced left upper limb swelling for 3 years. She sought medical attention at a local hospital 10 months ago, where magnetic resonance imaging revealed a 5-cm soft tissue mass. Needle biopsy performed at a local hospital resulted in the diagnosis of a spindle cell soft tissue sarcoma. The patient was referred to our hospital for limb salvage surgery with endoprosthetic replacement. She was initially diagnosed with a synovial sarcoma. Consequently, clinical management with chemotherapy was continued for the malignant sarcoma. Our pathology department also performed fluorescence in situ hybridization for result validation, which returned negative for SS18 gene breaks, indicating that it was not a synovial sarcoma. Next-generation sequencing was used to identify the SRF-RELA rearrangement. The final pathological diagnosis was a cellular/myofibroblastic neoplasm with an SRF-RELA gene fusion. The patient had initially received two courses of chemotherapy; however, chemotherapy was discontinued after the final diagnosis. CONCLUSION: This case was misdiagnosed because of its rare occurrence, benign biological behavior, and pathological similarity to soft tissue sarcoma.

Adult-Onset Multifocal Cutaneous Myofibromas: A Case Report of a Rare Entity.

Myofibromas are observed in both infantile and adult presentations, with key differences in the number and severity of lesions between these two groups. Infantile presentations encompass both indolent, isolated cutaneous lesions, as well as aggressive, multicentric presentations with visceral involvement. Adult myofibromas appear to be characterized by a single isolated cutaneous lesion, generally asymptomatic and following a benign clinical course. The occurrence of adult multifocal myofibromas has not yet been described in the literature. Here, we report a case of a 57-year-old female who presented with two minimally symptomatic soft tissue lesions on her right leg, with the pathologic findings of each lesion consistent with a cutaneous myofibroma. This case report describes a rare presentation of adult-onset multifocal cutaneous myofibromas.

Corneal Infantile Myofibromatosis Caused by Novel Activating Imatinib-Responsive Variants in PDGFRB.

Purpose: To investigate the genetic cause, clinical characteristics, and potential therapeutic targets of infantile corneal myofibromatosis. Design: Case series with genetic and functional in vitro analyses. Participants: Four individuals from 2 unrelated families with clinical signs of corneal myofibromatosis were investigated. Methods: Exome-based panel sequencing for platelet-derived growth factor receptor beta gene (PDGFRB) and notch homolog protein 3 gene (NOTCH3) was performed in the respective index patients. One clinically affected member of each family was tested for the pathogenic variant detected in the respective index by Sanger sequencing. Immunohistochemical staining on excised corneal tissue was conducted. Functional analysis of the individual PDGFRB variants was performed in vitro by luciferase reporter assays on transfected porcine aortic endothelial cells using tyrosine kinase inhibitors. Protein expression analysis of mutated PDGFRB was analyzed by Western blot. Main Outcome Measures: Sequencing data, immunohistochemical stainings, functional analysis of PDGFRB variants, and protein expression analysis. Results: We identified 2 novel, heterozygous gain-of-function variants in PDGFRB in 4 individuals from 2 unrelated families with corneal myofibromatosis. Immunohistochemistry demonstrated positivity for alpha-smooth muscle actin and ß-catenin, a low proliferation rate in Ki-67 (< 5%), marginal positivity for Desmin, and negative staining for Caldesmon and CD34. In all patients, recurrence of disease occurred after corneal surgery. When transfected in cultured cells, the PDGFRB variants conferred a constitutive activity to the receptor in the absence of its ligand and were sensitive to the tyrosine kinase inhibitor imatinib. The variants can both be classified as likely pathogenic regarding the American College of Medical Genetics and Genomics classification criteria. Conclusions: We describe 4 cases of corneal myofibromatosis caused by novel PDGFRB variants with autosomal dominant transmission. Imatinib sensitivity in vitro suggests perspectives for targeted therapy preventing recurrences in the future. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Unresectable infantile myofibroma discovered in utero.

The authors present a case of a proliferative nodule located beneath an infant's lower lip that was initially discovered on prenatal ultrasound and fetal magnetic resonance imaging (MRI). Biopsy revealed a smooth muscle actin-positive spindled cell proliferation with hemangiopericytoma-like vessels consistent with infantile myofibromatosis (IM). Since the location prevented surgical management, the clinicians opted to observe the lesion. Ultimately, the lesion fully regressed on its own confirming conservative management is an option for isolated IM.

Intramasseteric Solitary Myofibroma: A Case Report.

Solitary myofibroma or infantile myofibroma is a rare spindle cell neoplasm that generally affects infants before the age of 2 years but cases in young children and adults have been described. Although the location of infantile myofibroma in the oral and maxillofacial region has been described, the intramasseteric location of the lesion is very uncommon. A thorough assessment of histopathological and immunohistochemical characteristics is necessary to have a correct diagnosis. Treatment relies on surgical resection. In this article, we present a rare clinical case of a 15-year-old patient with a myofibroma of the masseteric muscle and its management.

Isolated infantile myofibroma of the calvarium: Report of a case with a literature review.

OBJECTIVE: Infantile myofibromatosis is a rare entity of childhood characterized by benign myofibroblastic tumors in the soft tissues, the bones, and occasionally the viscera. Solitary skeletal lesions are relatively uncommon. Calvarial involvement should be distinguished from more aggressive tumors for appropriate treatment. METHODS: We reviewed solitary infantile myofibroma of the calvarium and discussed the relevant computed tomography and magnetic resonance imaging findings along with differential diagnosis. A case study of the frontal bone in a 5-month-old girl was also presented. RESULTS: Fourteen cases were reviewed, including the current case. Of the 13 cases with known sex, eight were male and five female. The mean age was 3.03 with an age range of 0.41-9 years. Nine of the 14 tumors were in the frontal bone. The lesions were intradiploic with tabula interna and/or externa of the calvaria involvement. The mean largest diameter was 22.3 mm. Upon computed tomography, all the lesions were expansile and lytic, and hypoattenuated, isoattenuated or occasionally hyperatenuated. Calcification was not seen. On magnetic resonance imaging, most neoplasms were hypointense on T1-weighted and T2-weighted images. Neoplasms showed hypointense signal on diffusion-weighted imaging and hyperintense on apparent diffusion coefficient, without restricted diffusion in three cases. All lesions were intensely enhanced after gadolinium administration. Treatment was total surgical resection and recurrence was not observed during follow-up. CONCLUSIONS: Infantile myofibromas are rare, typically intradiploic expansile lytic lesions with tabula interna and/or externa involvement. Distinctive imaging features include the presence of hipointense signals on T2-weighted magnetic resonance images without restricted diffusion on diffusion-weighted imaging. A slow-growing, firm, painless, and nontender mass with supportive imaging findings should raise suspicion of the disease.

Myofibroma of the body of mandible: A case report of a solitary lesion.

Myofibromas are rare benign lesions and are often found as solitary entities. The treatment of the lesion is complete excision and the recurrence is rare. A 56-year-old female presented to the Oral and Maxillofacial Surgery clinic for further evaluation and management of a solitary lesion of the right body of the mandible that was first noticed incidentally by her referring dentist. An incisional biopsy was first performed in the clinic with the diagnosis of myofibroma. The patient was then treated with complete excision of the lesion and extraction of the adjacent teeth. The final biopsy report confirmed the initial diagnosis of myofibroma. Intraosseous solitary lesion of the mandible is a rare lesion with a handful of reported cases. Uniquely, the diagnosis of myofibroma in this 56-year-old is the oldest reported case of myofibroma. There are distinct histopathological features of the lesion that distinguishes this entity from other closely resembling lesions.

Myofibroma of mandibular alveolus: A case report.

Phenotypic heterogeneity has been a complex phenomenon lately, fetching attention in tumour pathology. Myofibroblastic differentiation is one such example and, besides, functional heterogeneity contributes to the biological behaviour of the tumours. Myofibroma is a distinctive neoplasm of myofibroblasts with a low incidence rate in the oral cavity. A case of myofibroma in mandibular alveolus in an adult patient is reported here for its rarity and diagnostic dilemma.

Solitary intraosseous myofibroma: a rare case diagnosed from mandibular fracture.

Intraosseous myofibroma is a rare tumor of benign nature, slow growth, and low morbidity. The aim of this article is to report a case of pathologic fracture associated with the incidental diagnosis of myofibroma in the mandible of an adolescent. A 15-year-old girl reported that she experienced a physical assault resulting in facial injuries 1 month previously and had since experienced severe pain, malocclusion, and chewing difficulty. The cone beam computed tomographic examination revealed multiple features suggestive of pathologic fracture associated with a hypodense lesion with lobulated limits, as well as expansion and thinning of the cortical bone in the left mandible. The histopathologic diagnosis of the lesion indicated myofibroma. Treatment consisted of enucleation and curettage of the lesion with reduction and internal fixation of the fracture. After 18 months, the osteosynthesis plates and an impacted mandibular third molar were removed. Curettage of the lesion in association with treatment of the mandibular fracture proved to be effective for both bone consolidation and absence of recurrence while restoring mandibular functionality.

Solitary, adult-onset, intraosseous myofibroma of the rib: a case report and literature review.

Myofibromas are rare benign tumors with myofibroblastic origin. They occur especially in cutis and subcutaneous tissue of the head and the neck, less frequently on the extremities. Myofibromas grow very slowly and are often painless, which is why patients often present relatively late. In the literature, there were many reports about intraosseous myofibromas of the craniofascial bones but reports of the trunk and extremities in adults are very rare. The authors present a very rare case of an intraosseous myofibroma of the ribs resulting in pathological fracture, including a research of literature from other cases of intraosseous myofibromas of the trunk or extremities.

Cellular myofibromas with SRF fusions: clinicopathological and molecular study of 3 cases of a rare entity and a potential mimic of sarcoma.

Cellular myofibromas/myopericytomas harboring recurring SRF fusions are recently characterized as rare and diagnostically challenging entities, which can mimic myogenic sarcomas. These tumors belong to the pericytic/perivascular myoid tumor family, which comprises a group of genetically heterogenous and sometimes morphologically overlapping entities. In this series, we describe 3 cases of SRF-rearranged cellular myofibromas/perivascular myoid tumors with a smooth muscle-like phenotype in children. The children ranged from 7 to 16 years of age, and all presented with a painless mass in the extremities, 2 of which were deep-seated. Histologically, the tumors demonstrated a smooth muscle-like morphology and immunophenotype with mild atypia and low-level mitotic activity. Prominent dense collagen deposition and coarse calcification was observed in 2 tumors. RNA sequencing revealed SRF fusions in all cases, with each tumor showing a different 3' partner gene, RELA, NFKBIE, and NCOA3. Of these, NCOA3 has not been reported previously, and this expands the molecular spectrum by identifying a novel fusion partner for SRF. Given that histological features can be worrisome for a myogenic sarcoma, wider awareness of this emerging tumor is valuable to avoid potential misclassification.

Radial nerve myofibroma: a rare benign tumor with perineural infiltration. Illustrative case.

BACKGROUND: Myofibromas are benign mesenchymal tumors, classically presenting in infants and young children in the head and neck region. Perineural involvement, especially in peripheral nerves within the upper extremity, is extremely rare in myofibromas. OBSERVATIONS: The authors present the case of a 16-year-old male with a 4-month history of an enlarging forearm mass and rapidly progressive dense motor weakness in wrist, finger, and thumb extension. Preoperative imaging and fine needle biopsy confirmed the diagnosis of a benign isolated myofibroma. Given the dense paralysis, operative management was indicated, and intraoperative exploration showed extensive involvement of tumor within the radial nerve. The infiltrated nerve segment was excised along with the tumor, and the resulting 5-cm nerve gap was reconstructed using autologous cabled grafts. LESSONS: Perineural pseudoinvasion can be an extremely rare and atypical feature of nonmalignancies, resulting in dense motor weakness. Extensive nerve involvement may still necessitate nerve resection and reconstruction, despite the benign etiology of the lesion.

Congenital Infantile Myofibroma: The Importance of Molecular Diagnosis.

Infantile myofibromatosis is an uncommon soft tissue neoplasm that may present at birth or in early infancy. Although rare, this neoplasm is one of the most common benign fibrous tumors of infancy. Even though these tumors do not spread, they can compress or damage nearby organs. There is not an established management protocol, but it is advisable to maintain periodic clinical and imagological control until stability. Watchful waiting is an option to consider in the absence of problematic symptoms and visceral involvement. We report a case of solitary infantile myofibromatosis, without visceral involvement. It showed an initial rapid growth, raising concern among medical doctors and motivating soft tissue biopsy, always recommended as the clinical picture deviates from the classic presentation. Histology interpretation is often challenging, making genetics and clinical evaluation essential to exclude and prevent the misdiagnosing of more aggressive lesions.

Non-familial paediatric oral myofibroma - A masquerade. Case report with a brief literature review.

Myofibromas are fibrous tumours that could be of familial or non-familial origin, belonging to the fibroblastic and myofibroblastic subset with a wide spectrum of clinical behaviour. Oral myofibromas present with a broad range of differential diagnoses, including benign and malignant lesions. Histopathologically, these lesions may imitate many other soft tissue tumours of the oral cavity, such as spindle cell tumours of nerve, smooth muscle cell origin, and other myofibroblastic lesions, thus leading to misdiagnosis and mistreatment. In the present paper, we report a soft tissue lesion, which presented as a growth on the gingivobuccal sulcus in a 7-year-old child. We also emphasise the various differential diagnoses that need to be eliminated and the importance of immunohistochemistry to know the nature of tumour cells in establishing the accurate diagnosis.

Imaging palpable tumors in pediatrics: Part 2.

Palpable tumors in children are a common reason for consulting a radiologist. The origin of these lesions varies widely, and although they are common, classic radiology books do not cover some of them. This series of two articles aims to review the clinical and radiological characteristics of a selection of palpable tumors in children that radiologists need to be familiar with.