Infantile myofibromatosis: the most common fibrous tumor of infancy

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 β-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.

Neonatal Dermatopathology: A 10-Year Institutional Review

BACKGROUND/OBJECTIVE

Neonatal skin conditions are typically diagnosed through noninvasive methods. Few studies describe the spectrum of biopsy- evaluated neonatal skin lesions. We present our institutional experience with the conditions leading to skin biopsies in neonates. The objective is to describe the conditions for which skin biopsies are performed in neonatal patients.

METHODS

There were 20 neonatal skin biopsies over a 10-year period from the hospital's delivery unit, NICU, and pediatric hospital. Biopsies were categorized as inflammatory (not caused by an infectious agent), congenital, neoplastic, infectious, and vascular conditions.

RESULTS

The patients' ages ranged from 1 day to 4 weeks, with a male predominance. There were 6 inflammatory, 7 congenital, 5 neoplastic, 1 infectious, and 1 vascular lesions.

CONCLUSIONS

The most frequent neonatal skin biopsy lesions were inflammatory or congenital lesions. This review described the types of neonatal dermatopathology specimens that we encountered in practice.

Infantile Myofibromatosis of the Femoral Neck: A Case Report

CASE

A 15-month-old boy who was being followed for developmental dysplasia of the hip because of breech presentation was discovered to have a solitary infantile myofibroma in the left femoral neck. The patient was avoiding weight-bearing on the affected extremity; thus, stabilization of the femoral neck was performed using a proximal femur locking plate. Postoperatively, he achieved all gross motor developmental milestones.

CONCLUSION

This report is the first to describe a solitary infantile myofibroma in the femoral neck and demonstrates the utility of operative stabilization of these lesions.

A retrospective study comprising 228 cases of pediatric scalp and skull lesions

BACKGROUND

Most neurosurgery presentations in children present with a mass that may be scalp and skull lesions, including neoplastic and congenital malformed structural lesions, respectively. Clinicians should make early diagnoses and identify cases requiring surgical intervention promptly to help achieve a better prognosis.

METHOD

This study retrospectively reviewed studies on children's scalp and skull lesions within a pediatric medical center's department of neurosurgery. The detailed clinical information and pathological types of these cases were scrutinized.

RESULT

A total of 228 children's scalp and skull lesions with clinical information and identified histopathology types were summarized. The most common scalp and skull lesions were benign dermoid cysts; malignant types were rare but can occur in children.

CONCLUSION

Based on the combined clinical symptoms and image information, children's scalp and skull lesions should be diagnosed early. Malignant scalp and skull lesions/other special cases should be treated seriously.

Prenatal genetic diagnosis of disseminated infantile myofibromatosis: a case report and literature review

BACKGROUND

Infantile myofibromatosis (IM) is a rare disorder characterized by the formation of nodules in the skin, muscle, bone, and, more rarely, visceral organs. Very few cases are detected prenatally, and the final diagnosis cannot be made until pathology is completed after birth. Here, we present a case of disseminated form IM (DFIM) with a diagnosis established on prenatal genetic grounds.

CASE PRESENTATION

A woman at 23 weeks of gestation was referred for ultrasound evaluation of fetal kidney abnormality. Generalized masses in the skin and muscle of the fetus developed at 28 weeks. Prenatal genetic testing identified the pathogenic heterozygous variant c.1681C > T (p.R561C) of the PDGFRB gene inherited from the asymptomatic father. Intrauterine demise occurred at 31 weeks. Autopsy confirmed DFIM with involvement of the heart and kidney. All cases of prenatally detected IM were reviewed, revealing an association of high mortality with DFIM.

CONCLUSIONS

Prenatal IM diagnosis is difficult. Initial detection is always based on ultrasound. DFIM has high mortality. The germline p.R561C mutation in PDGFRB may cause fetal demise due to severe visceral involvement of IM. Prenatal genetic testing provides a diagnosis before pathological results are available, leading to better counseling and management of pregnancy with a fetus with IM.

Generalized Infantile Myofibromatosis with Extensive Small Bowel Involvement in a Neonate

Infantile myofibromatosis is a rare benign congenital tumour that often regresses spontaneously but may pose therapeutic challenges in its widespread visceral form. We present the case of a full-term neonate with generalized infantile myofibromatosis including ubiquitous subcutaneous and muscular nodules, a tumour in the mastoid and disseminated intestinal involvement. The intestinal tumours led to a mechanical ileus with intestinal perforation within the first days of life. After partial small bowel resection and necessary proximal jejunostomy the boy was dependent on total parenteral nutrition. Chemotherapy with vinblastine and methotrexate was started and was temporarily supplemented with imatinib. Feeding stayed impossible despite tumour shrinkage. At the age of 4.5 months, restoration of intestinal continuity with further stricturoplasties was performed which - for the first time - allowed complete oral feeding. Chemotherapy was continued for further two months. Currently, the child is in good general condition with growth and further disease regression. This report suggests that massive visceral involvement of infantile myofibromatosis may require extensive intestinal surgery, as conservative therapy cannot resolve the disease and its sequelae.

A Unique Presentation of Multicentric Myofibromatosis in the Masseter Muscle of a Pediatric Patient

A 12-year-old female with a history of multicentric infantile myofibromatosis (IM) presented with a tender, enlarging cheek mass and trismus. Imaging identified an intramasseteric tumor. Given the unknown etiology of the tumor and her bothersome symptoms, the mass was excised using a transoral approach with concurrent facial nerve monitoring. Her pathology report confirmed the diagnosis of a myofibromatosis lesion embedded within the masseter muscle. While IM can often present with lesions in the head and neck region, the intramasseteric location is rare and presents unique considerations for surgical approach. Myofibromatosis lesions typically occur before two years of age, although there are some rare documented cases of multicentric myofibromatosis lesions presenting at older ages. Furthermore, this patient's family history of similar lesions suggests a familial variant, which may have implications for disease behavior and need for further work-up, monitoring, and management. Overall, this was an unusual presentation of IM given the patient's age, prevalent family history, and the location of the mass. This case report adds to the literature and discusses the clinical differential of a pediatric cheek mass, the surgical considerations for an intramasseteric tumor, and the natural history of infantile myofibromatosis.

Multicentric infantile myofibromatosis with extensive involvement limited to bone

Infantile myofibromatosis (IM) is the most common benign fibrous tumor of infancy, characterized by the development of single or multiple nodules in the skin, soft tissues, bone, and/or viscera. Multicentric forms are less frequent and can affect different tissues simultaneously and their prognosis depends on their extension and visceral involvement. Rarely, these forms are limited to the skeleton, in which case the absence of extraosseous lesions makes it difficult to suspect this entity. We present the case of an infant with multiple radiolucent lesions involving the skull, ribs, spine, and long bones, discovered in a radiological study performed after a minor trauma. A broad differential diagnosis was considered based on the osteolytic and polyostotic nature of the lesions on imaging studies. This report details and illustrates the typical radiological findings in bony involvement of IM, which suggest this disorder over other diagnostic options.

A Unique Case of Multicentric Infantile Myofibromatosis with Radiologic-Pathologic Correlation

Infantile myofibromatosis (IM) is a rare condition with a variable clinical presentation that characteristically affects young children. Most frequently it presents as one or more benign nodules of the skin, bones, soft tissues, or, rarely, visceral organs. According to the location and number of lesions, there are three different forms: solitary, multicentric without visceral involvement, and multicentric with visceral involvement (generalised), with the latter having the least favourable prognosis. We present a unique case of severe congenital generalised IM in a new-born male who required intubation and mechanical ventilation immediately after the birth due to respiratory distress. A chest radiograph showed numerous tumours involving the entire lung, resembling a metastatic lung disease. Additionally, the neonate had multiple, bluish, papular skin nodules and a biopsy of a skin nodule ultimately led to the diagnosis of IM. Diffuse lung involvement prevented adequate ventilation which resulted in multiorgan failure and death before targeted treatment could have been initiated. The presented case is unique, as such atypical extensive involvement of the lung and leptomeninges in IM has not been reported before. In this brief report, we present the findings of radiographic and ultrasonographic examinations in correlation with autopsy and histopathology.

Prenatally Diagnosed Infantile Myofibroma of Sartorius Muscle-A Differential for Soft Tissue Masses in Early Infancy

BACKGROUND

Infantile myofibromatosis (IM) is a soft tissue disease with solitary or multiple benign tumors, and an etiology still unknown. IM is a mesenchymal disorder of early infancy and is more frequent in males. IM may present as a solitary lesion of the skin, bone, muscle, subcutaneous tissue, located at the head, neck, and trunk, with good prognosis; or, as a multicentric form, with or without visceral involvement (heart, lung, gastrointestinal tract, kidney), with a poor prognosis. The definitive diagnosis of IM is confirmed by pathology. Treatment may be conservative, surgical, or chemotherapeutical.

CASE PRESENTATION

A two months old female patient, prenatally diagnosed at 30 weeks, presenting with a tumor on the antero-internal aspect of the left thigh. She was admitted due to rapid postnatal evolution, and the patient required surgery for tumor resection. Previously, clinically, biological and imaging investigations were performed, but the final diagnosis was histological and by immunostaining. The patient had a favorable postoperative outcome.

CONCLUSIONS

Despite its low frequency, IM should be considered in the differential diagnosis of soft tissue masses at an early age. The clinical form (solitary or multicentric), location, and visceral involvement will dictate the treatment and prognosis.

What to Look Out for in a Newborn with Multiple Papulonodular Skin Lesions at Birth

Multiple papulonodular skin lesions at birth can indicate the presence of various benign and malignant disorders. Although the lesions’ clinical aspect (color and consistency, in particular) may steer the clinician towards one disorder or another (infantile myofibromatosis, xanthogranuloma, or metastatic neuroblastoma), the diagnosis can only be confirmed by the histopathologic assessment of a biopsy. In neonates, a rapid but accurate diagnosis is critical because skin lesions may be the first manifestation of a malignant disorder like leukemia cutis or metastatic neuroblastoma. Here, we review the various disorders that may manifest themselves as multiple skin lesions at birth.

Testicular Myofibroma in Children: A Case Report and Review of the Literature

Testicular tumors are rare in the prepubertal population and often are germ cell tumors. Myofibroma is a rare spindle cell neoplasm composed of myofibroblasts, which are intermediate cells between fibroblasts and smooth muscle cells. Only two prepubertal testicular myofibromas have been previously reported. While cryptorchidism is a risk factor for testicular germ cell tumors, the exact etiology of testicular myofibroma is unknown. We report a case of testicular myofibroma in a six-year-old male with a history of undescended testes, as well as a review of the literature. This case suggests a possible connection between undescended testes and testicular myofibroma.

Segmental overgrowth and aneurysms due to mosaic PDGFRB p.(Tyr562Cys)

Activating variants in the platelet-derived growth factor receptor β gene (PDGFRB) have been associated with Kosaki overgrowth syndrome, infantile myofibromatosis, and Penttinen premature aging syndrome. A recently described phenotype with fusiform aneurysm has been associated with mosaic PDGFRB c.1685A > G p.(Tyr562Cys) variant. Few reports however have examined the vascular phenotypes and mosaic effects of PDGFRB variants. We describe clinical characteristics of two patients with a recurrent mosaic PDGFRB p.(Tyr562Cys) variant identified via next-generation sequencing-based genetic testing. We observed intracranial fusiform aneurysm in one patient and found an additional eight patients with aneurysms and phenotypes associated with PDGFRB-activating variants through literature search. The conditions caused by PDGFRB-activating variants share overlapping features including overgrowth, premature aged skin, and vascular malformations including aneurysms. Aneurysms are progressive and can result in morbidities and mortalities in the absence of successful intervention. Germline and/or somatic testing for PDGFRB gene should be obtained when PDGFRB activating variant-related phenotypes are present. Whole-body imaging of the arterial tree and echocardiography are recommended after diagnosis. Repeating the imaging study within a 6- to 12-month period after detection is reasonable. Finally, further evaluation for the effectiveness and safety profile of kinase inhibitors in this patient population is warranted.

Advances in the Diagnosis and Management of Neonatal Sarcomas

Neonatal sarcomas comprise a heterogeneous group of rare soft tissue neoplasms that present unique diagnostic and therapeutic challenges. Recent advances in molecular profiling have improved diagnostic capabilities and reveal novel therapeutic targets. Clinical trials demonstrate differences in behavior between sarcoma subtypes that allow for better clinical management. Surgical resection has been replaced with a multimodal approach that includes chemotherapy and radiotherapy. Despite these advances, neonates with sarcoma continue to fare worse than histologically similar sarcomas in older children, likely reflecting differences in tumor biology and the complexities of neonatal medicine. This review focuses on recent advances in managing neonatal sarcomas.

Diverse presentation and tailored treatment of infantile myofibromatosis: A single-center experience

BACKGROUND

Infantile myofibromatosis (IM) is a rare benign fibrous tumor with diverse clinical presentations and treatments, such as watchful waiting, surgical excision, and low-dose chemotherapy.

PROCEDURE

Clinical presentation and tailored treatment of five infants with solitary and generalized IM are described, together with a review of the literature.

RESULTS

Three patients underwent total-body magnetic resonance imaging (MRI) at diagnosis and during follow up, which revealed disease extension that aided in designing treatment. Visceral involvement included central nervous system, cardiac, gastrointestinal, muscle, bone, and subcutaneous tissue lesions. The patient with the solitary form of IM was followed up without treatment and had spontaneous improvement. Patients with the multicentric form received intravenous low-dose methotrexate and vinblastine chemotherapy. One patient who received oral methotrexate due to cardiac involvement and unfeasible central line access had excellent results. Recurrence was successfully treated by the same methotrexate and vinblastine regimen as that administered at diagnosis.

CONCLUSIONS

We suggest screening all patients with one or more IM lesions by means of total body MRI due to its inherent superior soft tissue resolution. Total-body MRI may also be used for routine follow up. Oral methotrexate can be administered successfully in patients that lack central line access, and recurrent lesions can be treated with the same chemotherapeutic combination as that given at diagnosis. Long-term follow up is needed, since recurrence could appear years after initial presentation of the disease.

Generalized infantile myofibromatosis with visceral involvement presenting as diffuse hypopigmented macules at birth

The initial clinical presentation of infantile myofibromatosis can vary from subtle skin changes to large tumors. Here, we describe a case of congenital generalized infantile myofibromatosis which presented with diffuse hypopigmented macules, some with subtle atrophy and telangiectasia. Further workup revealed visceral involvement which led to treatment with systemic chemotherapy. Awareness of this rare clinical presentation is crucial to expedite workup and treatment given the poor prognosis in infants with visceral involvement.

Infantile Myofibromatosis: 32 Patients and Review of Literature

BACKGROUND

Infantile myofibromatiosis (IM) is a rare benign tumor in the infants, but it has a bad prognosis if IM erncroaches on the viscera. Multiple tissues can be invaded by IM, including the subcutaneous tissue, the muscle of the neck, back, and head, but seldom in the bones and the viscera. The histopathologic and immunohistochemical examinations are necessary in daigonosis of IM as it might be misdiagnosed as the malignant tumor.

MATERIALS AND METHOD

Thirty-two consecutive patients with IM in our hospital (2003-2013) were enrolled and the clinical date were analyzed to understand IM better, such as the feature of clinical manifestations, pathology, imaging tests, and treatment.

RESULTS

All of them underwent excision operations, 4 of them with invasion in the bones, 2 with invasion in the craniums, and the rest in the ulna and the humerus. The immunohistiochemical analysis shown that the tumor cells were positive to vimentin and smooth muscle actin while negative to the S100 protein and desmin. Twenty-five patients were in follow-up, 2 cases recurred.

CONCLUSIONS

IM is a benign tumor, but IM with the viscera involvement has a bad prognosis. The strategy of waiting and observation for IM without visceral involvement could be selected.

Diagnostic limitations and considerations in the imaging evaluation of advanced multicentric infantile myofibromatosis

Infantile myofibromatosis, the most common fibrous tumor of infancy, is classified in 2 forms; as a solitary nodule or as numerous, widely-distributed multicentric lesions with or without visceral involvement. Although benign, multicentric myofibromas are still associated with a high incidence of morbidity and mortality due to the infiltration of critical structures. Herein, we present a case of an infant with aggressive PDGFRB and NOTCH3 mutation-negative myofibromas distributed throughout the vascular, respiratory, and gastrointestinal systems. The extensive disease resulted in pulmonary hypertension, respiratory failure and gastrointestinal obstruction refractory to chemotherapy and unamenable to surgical resection. Despite the presence of numerous highly invasive myofibromas, multiple imaging modalities largely underestimated, or even missed, tumors found at autopsy. This case demonstrates the limitations of radiographic imaging to assess disease burden in multicentric infantile myofibromatosis. The postmortem findings of extensive disease far exceeding what was demonstrated by multiple imaging modalities suggests that pediatricians should have a high index of suspicion for undetected tumors if clinical deterioration is otherwise unexplained.

Myofibroma/myofibromatosis: MDCT and MR imaging findings in 24 patients with radiological-pathological correlation

Background

The aim of this study was to characterize the radiological features of myofibroma on multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) and correlate the imaging findings with pathologic features.

Methods

The radiological findings of 24 patients with 29 myofibromas were retrospectively reviewed. All images were evaluated with emphasis on density, signal intensity, hypointense area, and enhancement, correlating these with pathologic findings.

Results

On plain MDCT scan, 4(26.7%) tumors were homogeneous isodensity, 4(26.7%) tumors were heterogeneous hyperdensity, and 7(46.7%) tumors were heterogeneous hypodensity. On contrast-enhanced MDCT scan, all tumors (9/9) showed heterogeneous enhancement with moderate in 3(33.3%) and marked in 6(66.7%) tumors, and their enhancements were higher compared to adjacent skeletal muscle (P = 0.0001). On MRI, heterogeneous slight hyperintensity, homogeneous slight hyperintensity, and heterogeneous hypointensity on T1-weighted imaging (T1WI) were observed in 14(82.3%), 1(5.9%) and 2(11.8%) tumors, respectively. On T2-weighted imaging (T2WI) and fat-suppressed (FS) T2WI, all tumors demonstrated heterogeneous hyperintensity. All tumors showed heterogeneous marked enhancement on FS contrast-enhanced T1WI. On T1WI, T2WI, FS T2WI, and FS contrast-enhanced T1WI, irregular strip or/and patchy hypointensities were found in 16(94.1%), 12(100%), 17(100%) and 17(100%) tumors, respectively, and pseudocapsule was seen in 5(29.4%) tumors. The hypointensities and pseudocapsule on MRI were exactly corresponding to pathological interlacing collagen fibers and fibrosis. The age of the recurrent group was lower than that of the non-recurrent group (P = 0.001) and the tumors without pseudocapsule were more likely to recur than those with pseudocapsule (P = 0.034).

Conclusion

Myofibromas are characterized by heterogeneous density or signal intensity, with moderate or marked enhancement. The hypointensities and pseudocapsule on MRI may be helpful in diagnosis, and the absence of pseudocapsule and younger age may be risk factors for tumor recurrence.

Massive infantile myofibromatosis of the upper lip causing airway distress in a newborn

Infantile myofibromatosis is a rare condition characterized by benign spindle cell tumors most commonly involving the head, neck, and chest. An infant female with a prenatal diagnosis of a large facial mass was delivered via Cesarean at 34 weeks. Sparse prenatal care was received. Following delivery, the neonate was found to have an 8 cm ulcerative mass involving the upper lip and philtrum. Respiratory distress developed, and mask ventilation was difficult secondary to the size of the mass. The patient was successfully intubated after numerous attempts and then transferred to the children's hospital. Additional imaging demonstrated similar masses within bilateral iliopsoas and gluteal muscles, and her right gastrocnemius. A biopsy confirmed infantile myofibromatosis. At two weeks of life, she underwent resection with bilateral myocutaneous advancement flaps and successful extubation. She received adjuvant vinblastine and methotrexate for her pelvic and extremity disease with excellent response. We present the first case of airway distress secondary to myocutaneous myofibromatosis.

Novel PDGFRB rearrangement in multifocal infantile myofibromatosis is tumorigenic and sensitive to imatinib

Infantile myofibromatosis (IM) is an aggressive neoplasm composed of myofibroblast-like cells in children. Although typically localized, it can also present as multifocal disease, which represents a challenge for effective treatment. IM has previously been linked to activating somatic and germline point mutations in the PDGFRβ tyrosine kinase encoded by the PDGFRB gene. Clinical panel-based targeted tumor sequencing of a tumor from a newborn with multifocal IM revealed a novel PDGFRB rearrangement, which was reported as being of unclear significance. Additional sequencing of cDNA from tumor and germline DNA confirmed a complex somatic/mosaic PDGFRB rearrangement with an apparent partial tandem duplication disrupting the juxtamembrane domain. Ectopic expression of cDNA encoding the mutant form of PDGFRB markedly enhanced cell proliferation of mouse embryo fibroblasts (MEFs) compared to wild-type PDGFRB and conferred tumor-forming capacity on nontumorigenic 10T1/2 fibroblasts. The mutated protein enhanced MAPK activation and retained sensitivity to the PDGFRβ inhibitor imatinib. Our findings reveal a new mechanism by which PDGFRB can be activated in IM, suggest that therapy with tyrosine kinase inhibitors including imatinib may be beneficial, and raise the possibility that this receptor tyrosine kinase might be altered in a similar fashion in additional cases that would similarly present annotation challenges in clinical DNA sequencing analysis pipelines.

Infantile Myofibroma Presenting as a Large Ulcerative Nodule in a Newborn

The differential diagnosis of a congenital cutaneous vascular-appearing mass in a newborn is broad and includes both benign and malignant tumors. We report the case of a newborn who presented with an erythematous exophytic skin nodule on the right upper leg. Excision was performed due to ulceration, concern for bleeding, and for diagnosis. Pathology revealed the mass to be an infantile myofibroma. This case highlights the importance of considering a broad differential diagnosis in a newborn with a cutaneous mass. While history, physical exam, and imaging can help diagnose some cases, a biopsy or excision is often needed to distinguish benign lesions from more concerning lesions.

PDGRFB mutation-associated myofibromatosis: Response to targeted therapy with imatinib

Heterozygous activating mutations in platelet-derived growth factor receptor B (PDGFRB) have been recently identified as a cause of autosomal-dominant infantile myofibromatosis. We describe a 36-year-old man with PDGFRB c.1681C>T (p.R561C) mutation. Upon progressive disease, the patient received treatment with imatinib and showed a remarkable response with remission of multiple lesions after 12 months. This is the first report of an adult patient with PDGFRB c.1681C>T mutation treated with imatinib.

Infantile myofibromatosis treated by mandibulectomy and staged reconstruction with submental flap and free fibula flap: a case report

BACKGROUND

Infantile myofibromatosis is the most common benign fibrous tumor in infants. Three different types have been reported in the literature. The most commonly affected areas are the head, the neck and the trunk. Our patient showed a very high level of mandibular destruction resistant to all mandibular sparing treatment strategies requiring segmental mandibulectomy and complex reconstruction.

CASE PRESENTATION

We describe a rare case of multicentric infantile myofibromatosis with mandibular bone destruction. The treatment required a succession of chemotherapy, a subtotal transoral resection and a hemi-mandibulectomy. The mandibular reconstruction was staged with initial bridging titanium plate with a submental flap, followed later by a fibula free flap.

CONCLUSION

Mandibular involvement by myofibromatosis is rare, and the extend of bone destruction and reconstruction make this case unique. To our knowledge, this is the only reported case of fibula free flap mandibular reconstruction in a patient with infantile myofibromatosis , as well as one of the youngest reported submental island flaps for any pathology. We describe the clinical presentation and management, including relevant imaging, histopathology, medical and surgical treatment as well as a review of relevant literature.

A Rare Case of Infantile Myofibromatosis Presenting to the Emergency Department as Undiagnosed Long Bone Fractures

Infantile myofibromatosis is a disorder of mesenchymal tumors that usually presents within the first 2 years of life. Most patients initially present because of the presence of visible or palpable subcutaneous tumors. We report a case of a fussy 5-week-old infant who presented to an emergency department with bilateral femur fractures initially thought to be due to nonaccidental trauma or a metabolic bone disorder. She was ultimately diagnosed after admission with infantile myofibromatosis after taking an extensive family history and after further laboratory and radiologic evaluation. There are no previously published cases of undiagnosed infantile myofibromatosis presenting to the emergency department, especially with multiple long bone fractures.

Solitary myofibroma of the lumbar vertebra in young adult: A case report with 4-year follow-up of postoperative CT or MRI

BACKGROUND

Solitary myofibroma of the spine is extremely rare, particularly among adults. To the best of our knowledge, only 3 cases affecting lumbar vertebrae have been reported in the English language literature. Of them, only 1 case was an adult case of solitary myofibroma affecting the L1 vertebra.

METHODS

We report a case of solitary myofibroma affecting the L5 vertebra in an 18-year-old man and the postoperative imaging of solitary myofibroma for the first time. Conventional radiographs demonstrated an expansile osteolytic lesion with thinned cortex and marginal sclerosis. Computed tomography (CT) showed a purely osteolytic expansile lesion with partial disappearance of thinned cortex. MRI of the lesion revealed an isointense signal on T1-weighted images, an inhomogeneous slightly hyperintense signal on T2-weighed images, and homogeneous avid enhancement with gadolinium.

RESULTS

Surgical excision was performed and the lesion was diagnosed as solitary myofibroma on pathological examination. One-year follow-up postoperative CT demonstrated decreased size of the osteolytic lesion with sclerotic change. Four-year follow-up postoperative MRI revealed complete resolution of the lesion replaced by normal fatty marrow.

CONCLUSION

If a benign-looking expansile osteolytic lesion reveals a homogeneously isointense signal on T1-weighted image, inhomogeneous slightly hyperintense signal on T2-weighted image, and homogeneous avid enhancement with gadolinium, solitary myofibroma should be considered in the differential diagnosis of spine bone tumors. It can be resolved completely.

STAT6 Reliably Distinguishes Solitary Fibrous Tumors from Myofibromas

Solitary fibrous tumors (SFT) and myofibromas (MF) historically have belonged to the same morphologic spectrum and have been lumped together under the nonspecific umbrella term, "hemangiopericytoma" along with other pericytic/myoid tumors. While current evidence shows clear distinction between the two entities, they frequently remain in the same histopathologic differential diagnosis. This diagnostic dilemma especially is common for smaller incisional biopsies from the oral cavity. STAT6 immunohistochemistry (IHC) recently was established as a reliable method to detect solitary fibrous tumor; however, the literature is sparse regarding STAT6 reactivity in MFs. The authors report ten new cases of oral solitary fibrous tumor, discuss histopathologic similarities and differences between the two tumors, and list respective STAT6 IHC expressivity. After IRB approval, 10 cases diagnosed as SFT and 24 cases of MF were collected from the University of Florida Oral and Maxillofacial Pathology Biopsy Service between the years 1994 and 2016. The original hematoxylin and eosin slides and related IHC were reviewed. IHC with STAT6 antibody was performed on all 34 samples, and the findings were analyzed. All cases were from the oral cavity or perioral regions. 10/10 SFTs expressed STAT6 nuclear reactivity, while no cases of MF showed nuclear expression of STAT6. STAT6 is a dependable marker to differentiate SFTs from MFs.

Putative Intravascular Myofibroma Mimicking a Vascular Malformation With Phleboliths

Myofibroma is a rare, benign myofibroblastic tumor that commonly presents at birth or in early infancy, usually as a painless, slow-growing, solitary, nodular mass. We present a case of a 40-year-old woman with a painful, solitary, myofibroma on the right elbow. The unique features of this case include age and gender of the patient, site, pain on presentation, tumor morphology, and putative intravascular nature of the tumor.

Mimickers of Infantile Hemangiomas

Infantile hemangiomas (IHs) are the most common tumors of infancy and usually follow a typical course of growth and involution. We report four soft tissue tumors that were referred to the pediatric dermatology clinic as IHs and the process by which they were diagnosed and treated. Clinicians should be aware of presentations of these uncommon, but serious soft tissue tumors. Many of these mimickers have a vastly different clinical prognosis, and early intervention to limit sequelae is crucial. Biopsy of atypical lesions should be considered early in the diagnostic process since they have varied prognosis and treatment strategies.

Myofibroma in Infancy and Childhood

Myofibromas are rare fibroblastic-myofibroblastic tumors in children. Their biological behavior is unpredictable and spontaneous regressions have been described. This is a retrospective review of clinical characteristics, treatment, and outcome of children diagnosed with myofibroma between 1999 and 2013 at Texas Children's Hospital. The median age at diagnosis of 42 patients was 37 months. Approximately two thirds of the patients were male. The median length of follow-up was 50.5 months (range, 0 to 165 mo). Thirty-eight patients (90%) had solitary lesions; 19 (50%) in the head and neck, 10 (26%) in the limbs, and 9 (24%) in the trunk. Twelve patients underwent a complete surgical resection. Of the 30 patients with positive margins, only 1 had tumor progression. Two patients had multicentric involvement, and 2 patients had generalized disease with visceral involvement. One patient with generalized disease and a progressive maxillary sinus mass was treated with vinblastine and methotrexate chemotherapy followed by complete surgical resection. All patients were alive at last follow-up. Myofibromas of childhood demonstrate clinical variability, and may spontaneously regress. Positive surgical margins do not adversely affect outcome. The rare patient with progressive unresectable disease may benefit from chemotherapy.

The spectrum of infantile myofibromatosis includes both non-penetrance and adult recurrence

Infantile myofibromatosis is characterized by benign myofibroblastic tumors within skin, muscle, bone or viscera which have a characteristic staining pattern on immunohistochemistry. The condition typically presents in infancy and the tumors often disappear by the third year of life. Mutations in the PDGFRB gene and NOTCH3 genes have been identified in familial forms of the condition. We present two families with molecularly confirmed germline mutations in the PDGFRB gene, one demonstrating a phenotype ranging from complete non-penetrance to neonatal lethality; and the other illustrating adult recurrence of the tumors.

Unusual Presentation of Infantile Myofibroma in the Deep Palm of a Child: A Case Report and Discussion of the Differential Diagnosis

Infantile myofibroma or myofibromatosis is a myofibroblastic and fibroblastic proliferation that is most commonly reported in children younger than 2 years of age. It is a benign process composed histologically of a biphasic pattern of spindle-shaped cells surrounding a zone of less differentiated cells in a hemangiopericytoma-like pattern. We report this tumor in a unique presentation in the deep palm of a 2-year-old child without skin ulceration and with an intimate association with the median nerve. The well-circumscribed nature of the tumor facilitated complete excision with neural preservation. Final pathology was consistent with an unusual type of myofibroma or myofibromatosis. Conservative management with partial excision has been advocated for these masses because of potential surgical morbidity and its benign nature. This case report highlights the differential diagnosis of uncommon soft tissue tumors in the pediatric hand as well as the importance of a surgeon's surgical assessment in guiding treatment.

Evolution of Fibroblastic Connective Tissue Nevus in an Infant

Fibroblastic connective tissue nevus (FCTN) is a rare and recently described neoplasm of fibroblastic/myofibroblastic lineage. We report a case of a 1-month-old healthy male infant who presented with a dermal plaque on the upper chest since birth. A punch biopsy demonstrated a dermal spindle-cell neoplasm with variable smooth muscle actin positivity and negative staining for CD34, consistent with myofibroma. Over the course of the next year, the remaining lesional tissue exhibited clinical softening and a surgical excisional specimen revealed histologic findings distinct from the original biopsy. These included a poorly circumscribed proliferation of bland spindle cells arranged in short fascicles centered in the dermis and extending into the subcutis with positivity for CD34, and absence of staining with smooth muscle actin features diagnostic of FCTN. Our case allowed the opportunity to see this unusual neoplasm at different stages, and we hypothesize that FCTN may undergo an early cellular phase and that time is required for these lesions to "mature" and demonstrate the more characteristic features of FCTN.

Extracalvarial Composite Infantile Myofibromatosis: Case Report and Literature Review

Infantile soft tissue tumors of the head are very rare and the majority of them are myofibromas. The authors present the case of a 1-day-old boy with a scalp tumor with several distinct histopathological features including myofibroma, hemangiopericytoma, and fibrosarcoma consistent with the diagnosis of composite infantile myofibromatosis. Genetic testing was negative for trisomy 17, translocation (12; 15), FUS, and ETV6 translocations. Despite the ominous histopathological features, the clinical course was benign. The authors review here available literature concerning current concepts of making the diagnosis of composite infantile myofibromatosis and discuss treatment options.

[Skin tumors in children]

The presence of a congenital or acquired cutaneous lesion is a frequent reason for consultation in pediatric plastic surgery unit. The management of these lesions requires a good knowledge of specific diagnoses in children. This step is sometimes difficult because of the multiplicity of possible diagnosis. Some skin tumors may be the external sign of a general disease or an underlying malformation; those can change the overall prognosis and management and require to be properly identified. The decision of surgical excision depends on various criteria, including diagnosis but also the reconstruction possibilities. The timing of surgical treatment depends on the medical emergency of the tumor resection (benign tumor, spontaneously regressive tumor, risk of degeneration into malignancy), on the cosmetic and psychological impact but also on the growth or learning steps in child life. This article first provides an aid in the diagnosis of the most common or more characteristic skin tumors. The algorithm is principally based on the pigmentation aspect of the tumor. The age and conditions of the surgical management are specified for each type of tumor. Cutaneous hemangiomas and vascular malformations, and congenital cysts and fistulas are not reported in this article.

An unusual cause of neonatal hip dislocation: infantile myofibromatosis presenting as developmental dysplasia of the hip

INTRODUCTION

Infantile myofibromatosis (IM) is a rare paediatric fibrous tumour also known as a desmoid tumour that occurs in around 1:150000 live births. It manifests as solitary or multicentric fibrous masses in the musculoaponeurotic soft tissues and can affect the visceral organs and bones.

CASE DISCUSSION

We report a case of infantile myofibromatosis of the gluteus maximus muscle in an 18-day old neonate presenting atypically as a case of developmental dysplasia of the hip due to local involvement of the sciatic nerve. However, failure of improvement with conventional management and clinical wasting of the lower leg muscles was indicative of a secondary cause of the patient's hip dislocation, which was confirmed on imaging and surgical biopsy.

DISCUSSION

This case report aims to emphasise the importance of considering secondary causes of neonatal hip dislocation, especially in cases where imaging findings are atypical of conventional DDH. Although imaging appearances on ultrasound and CT may vary, the signal characteristics and enhancement pattern of soft tissue myofibromata on MRI with and without gadolinium contrast appear to be the most consistent finding in these cases.

Infantile Myofibromatosis

Background:

Infantile myofibromatosis is a rare condition that usually presents in infancy.

Objective:

The purpose of this article is to report a new case of late-onset infantile myofibromatosis and to review the literature regarding similar cases.

Methods:

A Medline search was performed, and a new case is reported.

Results:

The solitary tumour presented by the 9-year-old boy is histologically proven to be compatible with the diagnosis of infantile myofibromatosis.

Conclusion:

Although infantile myofibromatosis usually presents in infancy, onset may occur in childhood.

Solitary Myofibroma of the Bladder Trigone in a 3-Month-Old Patient: First Case Report

Visceral solitary myofibromas are uncommon in childhood. We report a case of a solitary asymptomatic visceral myofibroma of the bladder trigone occurring in a 3-month-old boy. Once malignancies were ruled out by cystoscopy, radical excision was performed in order to avoid any potential impairment of bladder dynamic. Postoperative course was uneventful and patient was discharged on day 3 after surgery. After 36 months of follow-up, the patient is toilet-trained and remains well; bladder function is normal.

Transcatheter management of mid-aortic syndrome secondary to myofibroma presenting in infancy with severe left ventricular dysfunction: a case report

In this study, we summarise a case of a myofibroma causing mid-aortic syndrome due to obstruction of the distal thoracic and abdominal aorta leading to severe left ventricular dysfunction. The patient was managed with percutaneous intervention via balloon dilation and stent placement. On follow-up, the patient has normalisation of ventricular function, is off anti-hypertensives, and is being monitored for re-stenosis.