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.

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.

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.

[Pediatric myofibroma/myofibromatosis of the soft tissue and bone: a clinicopathological analysis of 28 cases].

Objective: To investigate the clinicopathological features, diagnosis and differential diagnosis of pediatric myofibroma/myofibromatosis of the soft tissue and bone. Methods: All cases of pediatric myofibroma/myofibromatosis of the soft tissue and bone diagnosed between January 2011 and December 2018 were retrieved from the surgical pathology records in the Department of Pathology, Beijing Jishuitan Hospital, Beijing, China. Clinical and radiological data were collected. H&E and immunohistochemistry were used to examine histological and immunophenotypic features and to make the diagnosis and differential diagnosis. The relevant literature was also reviewed. Results: Twenty-eight cases of pediatric myofibroma/myofibromatosis of the soft tissue and bone were respectively collected. The patients' ages ranged from 2 months to 14 years, with a mean age of 7 years. There were 7 females and 21 males. There were 12 cases located in soft tissue, including the finger (n=9), upper arm (n=1) and foot (n=2). There were 14 cases located in the bone of limb, including the femur (n=8), tibia (n=4), clavicle (n=2), fibula (n=2) and radius (n=1). There were 2 cases of myofibromatosis involving multiple bones. Radiology showed lytic lesions in the bone. The proliferation of spindle-shaped myofibroblasts arranged in fascicles with indistinct eosinophilic cytoplasm and bland nuclei, with no pleomorphism and cytological atypia. The characteristic histologic structure was the biphasic nodular growth pattern with cellular and paucicellular regions. The tumors might arrange in a hemangiopericytoma-like pattern. The stroma varied between dense fibrosis and myxoid changes. The reactive new bone formation and inflammatory cell infiltration also existed. Immunohistochemical study showed that the SMA was positive. The surgical resections were performed. One of the patients had tumor recurrence as a result of 11-month follow-up. Conclusions: The pediatric myofibroma/myofibromatosis of the soft tissue and bone is a very rare benign tumor and has a good prognosis. It has a characteristic morphology and its differential diagnosis from other spindle cell tumors could be made with the immunohistochemical analysis.

Pediatric myofibroma/myofibromatosis of the soft tissue and bone: a clinicopathological analysis of 28 cases / 中华病理学杂志

Objective: To investigate the clinicopathological features, diagnosis and differential diagnosis of pediatric myofibroma/myofibromatosis of the soft tissue and bone. Methods: All cases of pediatric myofibroma/myofibromatosis of the soft tissue and bone diagnosed between January 2011 and December 2018 were retrieved from the surgical pathology records in the Department of Pathology, Beijing Jishuitan Hospital, Beijing, China. Clinical and radiological data were collected. H&E and immunohistochemistry were used to examine histological and immunophenotypic features and to make the diagnosis and differential diagnosis. The relevant literature was also reviewed. Results: Twenty-eight cases of pediatric myofibroma/myofibromatosis of the soft tissue and bone were respectively collected. The patients' ages ranged from 2 months to 14 years, with a mean age of 7 years. There were 7 females and 21 males. There were 12 cases located in soft tissue, including the finger (n=9), upper arm (n=1) and foot (n=2). There were 14 cases located in the bone of limb, including the femur (n=8), tibia (n=4), clavicle (n=2), fibula (n=2) and radius (n=1). There were 2 cases of myofibromatosis involving multiple bones. Radiology showed lytic lesions in the bone. The proliferation of spindle-shaped myofibroblasts arranged in fascicles with indistinct eosinophilic cytoplasm and bland nuclei, with no pleomorphism and cytological atypia. The characteristic histologic structure was the biphasic nodular growth pattern with cellular and paucicellular regions. The tumors might arrange in a hemangiopericytoma-like pattern. The stroma varied between dense fibrosis and myxoid changes. The reactive new bone formation and inflammatory cell infiltration also existed. Immunohistochemical study showed that the SMA was positive. The surgical resections were performed. One of the patients had tumor recurrence as a result of 11-month follow-up. Conclusions: The pediatric myofibroma/myofibromatosis of the soft tissue and bone is a very rare benign tumor and has a good prognosis. It has a characteristic morphology and its differential diagnosis from other spindle cell tumors could be made with the immunohistochemical analysis.

Solitary cutaneous infantile myofibroma as a hallmark of myofibromatosis: Two cases and review of the literature.

Infantile myofibroma (IM) commonly presents as a benign cutaneous fibrous tumor in infancy. Although the majority of solitary IM regress without any morbidity, some cases have underlying bone or visceral involvement that can lead to both morbidity and mortality. In this report with review of the literature, we present two cases of solitary cutaneous IM with internal involvement and discuss screening cases of solitary IM with full body imaging.

Myofibromatosis.

INTRODUCTION: Myofibromatosis is a distinctive mesenchymal disorder occurring predominantly in childhood, which on microscopy shows peripheral light areas of spindle cells and central cellular areas of primitive oval to spindle cells arranged around hemagiopercytomatous vessels. PDFGRB mutations in the familial and multifocal sporadic forms and SRF-RELA fusions in the cellular variants have been identified. The index case is being presented to discuss the clinico-pathological features, differential diagnosis, and management of the lesion. CASE PRESENTATION: An 11-year-old male presented with an infraorbital mass of 3 months duration. The mass was excised and microscopy revealed the morphological features of myofibroma with tram-track SMA immunopositivity. Nodular fasciitis and fibromatosis were the differentials considered. CONCLUSION: The SRF-RELA gene fusion may represent a subset that in the future may be used to differentiate these myofibromas/myopericytomas from the ACTB-GLI fusion myopericytomas, and PDGFRB may be used to perhaps separate out familial myofibromas from other myofibromas.

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.

Genetic testing and surveillance in infantile myofibromatosis: a report from the SIOPE Host Genome Working Group.

Infantile myofibromatosis (IM), which is typically diagnosed in young children, comprises a wide clinical spectrum ranging from inconspicuous solitary soft tissue nodules to multiple disseminated tumors resulting in life-threatening complications. Familial IM follows an autosomal dominant mode of inheritance and is linked to PDGFRB germline variants. Somatic PDGFRB variants were also detected in solitary and multifocal IM lesions. PDGFRB variants associated with IM constitutively activate PDGFRB kinase activity in the absence of its ligand. Germline variants have lower activating capabilities than somatic variants and, thus, require a second cis-acting hit for full receptor activation. Typically, these mutant receptors remain sensitive to tyrosine kinase inhibitors such as imatinib. The SIOPE Host Genome Working Group, consisting of pediatric oncologists, clinical geneticists and scientists, met in January 2020 to discuss recommendations for genetic testing and surveillance for patients who are diagnosed with IM or have a family history of IM/PDGFRB germline variants. This report provides a brief review of the clinical manifestations and genetics of IM and summarizes our interdisciplinary recommendations.

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.

[Left mandibular infantile myofibromatosis: a case report].

Infantile myofibromatosis is a rare benign childhood myofibroblastoma. A case of infantile myofibromatosis of the left mandible was reported, and relevant literature was reviewed to discuss the clinical characteristics, pathogenesis, imaging characteristics, pathological characteristics, differential diagnosis, and the treatment of the tumor to improve the understanding of the tumor.

Ultrasonography of Pediatric Superficial Soft Tissue Tumors and Tumor-Like Lesions.

Ultrasonography (US) is usually the first imaging examination performed to evaluate palpable or visible superficial soft tissue lesions that are common in children. Although clinical assessments, such as age at presentation, clinical course, and overlying skin discoloration, are important for the differentiation of pediatric soft tissue lesions, US allows a specific diagnosis of some typical benign lesions and helps in guiding further investigation since it provides detailed information about the lesion location, characterization including solid versus cystic, vascularity, and compressibility. Therefore, sufficient knowledge of the normal anatomy, proper ultrasonographic techniques, and the imaging findings of common and uncommon soft tissue lesions in children are crucial for accurate assessment and management of patients. In this article, we review the techniques and imaging findings focusing on the ultrasonographic features of a variety of superficial soft tissue lesions detected in children.

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.

Gynecology and Oncology Fetal Myofibromatosis: A Challenge for Prenatal Diagnosis Mini Review of the English Literature.

IMPORTANCE: Infantile myofibromatosis (IM) is a benign neoplasm with a reported incidence of 1:150,000. The "solitary" type is characterized by a single lesion in the skin, muscle, or bone, whereas the "multicentric" type may also involve the viscera. OBJECTIVE: This report describes the prenatal diagnosis of IM and recommendations for future pregnancy follow-up. EVIDENCE ACQUISITION: This systematic search of the English literature yielded 8 reports documenting prenatal diagnosis of IM between 1999 and 2018. RESULTS: Fetal age at diagnosis ranged from 13 to 38 weeks of gestation. Seven cases were diagnosed in the third trimester (30-34 weeks). Five cases were of the "solitary" type, and all successfully underwent surgical removal of the tumor with a good outcome. Three were of the "multicentric" type, and the 1 infant presenting with diffuse disease died several weeks after delivery. CONCLUSION AND RELEVANCE: The prenatal diagnosis of IM is often not made until the third trimester following a normal second-trimester anomaly scan, likely due to development of this lesion over time. Women should be referred for genetic counseling and consideration of preimplantation genetic diagnosis following the delivery of an affected child with the autosomal recessive form of the disorder and identified causative pathogenic variants.

Prenatal sonography of multicentric infantile myofibromatosis: Case report and review of the literature.

Scant literature exists on prenatally diagnosed infantile myofibromatosis (IM). We report a case of multicentric IM, which was first recognized as a soft-tissue paraspinal mass on prenatal sonography and subsequently characterized by MRI with pathological confirmation.