An Historic Perspective of Infantile Myofibromatosis

Solitary Intraosseous Myofibroma of the Mandible in a Nine-Year-Old Child: A Case Report and Literature Review

Myofibroma (MF) is a benign neoplasm derived from myofibroblasts. While they are infrequent, these tumors are predominantly found in the pediatric group and seldom manifest as intraosseous mandibular tumors. Herein, we present a 9-year-old female with a radiolucent lesion in the left mandible associated with malposed left lower canine and 1st premolar teeth. Clinical examination revealed a slightly tender 5×4 cm firm mass resulting in an expansion of the buccal and lingual aspects of the mandible in the canine and first premolar region. An incisional biopsy revealed a benign tumor consisting of spindle cells organized in fascicles, alongside dispersed thin-walled blood vessels. Tumor cells tested positive for α-smooth muscle actin (SMA) and vimentin. Given these findings, a diagnosis of MF was established. To the best of our knowledge, only 45 cases of solitary MF of the mandible have been reported in the pediatric age group in the literature. We describe one additional case and provide a review of the literature.

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.

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.

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.

[Pediatric tumors with spindle cell morphology]

Spindle cell tumors in childhood are rare lesions with a heterogeneous morphological picture and clinical course, ranging from benign lesions to fully malignant tumors. The clinical assessment of these tumors is often challenging since some of them show fast growth dynamics but are utterly benign, while a subset of slow-growing tumors can represent malignant entities. Due to the rarity of these tumors as well as the overlapping morphology and the often uncharacteristic immunohistochemical profiles, the pathologic diagnosis is often also difficult. This review gives an overview of some of the more common pediatric spindle cell tumors. In addition to the morphological features and immunohistochemical aspects, specific molecular changes are discussed. Here, some of the newly described translocations that may imply therapeutic options, are presented.

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.

Multiple Bone Lesions in an 8-Month-Old Child Presenting with Pathologic Fracture: A Rare Case of Solely Osseous Multicentric Infantile Myofibromatosis

CASE

An otherwise healthy 8-month-old boy presented with a pathologic fracture of the distal aspect of the radius. Further work-up demonstrated widespread osseous lesions of the axial and the appendicular skeleton with no soft-tissue or visceral involvement.

CONCLUSION

Infantile myofibromatosis has a spectrum of severity that demands a careful and complete work-up. In rare cases such as the present one, it can manifest as multiple osseous lesions. The patient in the present case was managed conservatively, with no morbidity demonstrated at 1 year of follow-up.

Chemotherapy for Generalized Infantile Myofibromatosis With Visceral Involvement

Infantile myofibromatosis (IM) is most commonly limited to cutaneous lesions that resolve spontaneously. However, generalized IM with visceral involvement, which has a reported mortality rate as high as 73%, has been successfully treated with a combination of methotrexate and vinblastine. Here we report the further efficacy of low-dose methotrexate and vinblastine in 2 pediatric patients with IM and visceral involvement and review the literature describing chemotherapy for these patients.

Head and neck solitary infantile myofibroma: Clinicopathological and immunohistochemical features of a case series

Infantile myofibroma is a rare mesenchymal benign tumor mostly found in the head and neck region. The aim of this study was to describe a small case series of head and neck solitary infantile myofibroma, emphasizing the importance of the histopathological and immunohistochemical features, and the potential diagnostic challenges. For the study, clinical and imaging data were obtained from the medical records. All cases were histologically reviewed, and immunohistochemical analyses were performed to confirm the diagnosis. Four cases of head and neck solitary infantile myofibroma were identified. All patients were females and presented a mean age of 3 years old (ranging from 2 to 6 years). The site of the tumors were the mandible, right cheek, subcutaneous tissue adjacent to basal cortical of the mandible and upper anterior gingiva. No symptoms, such as pain or paresthesia, were reported. Computerized tomography revealed well-delimited tumors. All tumors were positive for vimentin and alpha-smooth muscle actin. All patients underwent surgical excision and no signs of recurrence were observed after long-term follow-up. In summary, head and neck solitary infantile myofibromas are rare and present excellent prognosis. The correlation between clinical, histopathological and immunohistochemical features are essential for a correct diagnosis.

Solitary infantile myofibromatosis in the bones of the upper extremities: Two rare cases and a review of the literature

Infantile myofibromatosis (IM) is the most common fibrous tumor of infancy. IM may arise in a solitary or multicentric form, with similar histopathological findings, however, the clinical features and prognoses may vary. The solitary form tends to occur predominantly in males and is typically observed in the dermis, subcutis or deep soft tissues. The reported incidence of solitary osseous myofibromatosis is rare. Furthermore, the majority of solitary IM cases of the bone occur in the craniofacial bones, while the occurrence of solitary osseous myofibromatosis on the extremities has been sporadically reported. The present study describes two cases of solitary IM involving the bones of the upper extremities in females who were over two years old. The cases show unusual symptom presentation and the tumor origin is in a rarely observed location. The study discusses the clinical, radiological and pathological features, in addition to the previously described etiology, prognosis and treatment options for this condition.

Fibroblastic and myofibroblastic tumors in children and adolescents

Fibroblastic and myofibroblastic tumors in children and adolescents are a relatively common group of soft tissue proliferations that range from reactive to hamartomatous to neoplastic, with a full spectrum of benign, intermediate, and malignant neoplasms. These lesions are diagnostically challenging because of morphologic and immunohistochemical overlap, despite significant clinical, genetic, and prognostic differences. The fibromatoses are a major subgroup, and all types of fibromatoses can occur in the 1st 2 decades of life. Intermediate and malignant fibroblastic-myofibroblastic tumors are an important group that includes variants of fibrosarcoma and other tumors with recurrent cytogenetic or molecular genetic abnormalities and low metastatic potential. Pathologic examination is enhanced by adjunct techniques, such as immunohistochemistry, cytogenetics, and molecular genetics, although morphology provides the ultimate criteria for a specific diagnosis. This article reviews the clinicopathologic features of fibroblastic and myofibroblastic tumors with an emphasis on the unique aspects of these neoplasms in children and adolescents, the use of diagnostic adjuncts, and differential diagnoses.

Infantile myofibroma or lymphatic malformation: differential diagnosis of neonatal cystic cervicofacial lesions

A 5-day-old male neonate was referred to our vascular anomalies center with a large cystic submandibular mass. History and physical examination and ultrasonographic results indicated the diagnosis to be macrocystic lymphatic malformation. Consequently, the child was treated with sclerotherapy and subtotal excision. The histopathological examination result showed that the lesion was infantile myofibroma. This diagnostic error was attributed to atypical features of infantile myofibroma in this child: unusually large cysts, rapid enlargement, and coagulopathy. This report expands the clinical spectrum of infantile myofibromatosis and suggests its consideration in the differential diagnosis of neonatal cystic cervicofacial lesions.

A rare case of infantile myofibromatosis and review of literature

Infantile myofibromatosis is a rare benign tumor-disease (1/400,000). Four different types have been reported in literature. The most commonly affected body areas are the head, the neck, and the trunk. We would like to present a rare case of a multicentric type with singular visceral involvement and a literature review of all case series with more than five patients. A 9-month-old boy presented with a swelling on the medial side of his proximal left tibia. The lesion which was present since birth, was well palpable, indolent, hard, and mobile in relation to the surrounding tissue. Radiographic films and ultrasound examination presented a pretibial soft-tissue tumor mass with calcifications and two osteolytic lesions with a sclerotic rim. A skeletal survey showed more osteolytic lesions, but the magnetic resonance imaging showed no more soft-tissue lesions. The rapid frozen section biopsy hinted at the diagnosis of histiocytosis X. The definitive histological result 6 days later was infantile myofibromatosis. As therapy, we determined a wait-and-see policy with controls all 3 months. At 20 months follow-up, the boy showed beginning of regression of all lesions. Infantile myofibromatosis is a very rare benign tumor-disease. Radiologically often soft-tissue masses with calcifications and osteolytic lesions with sclerotic rims are described. These findings also can be interpreted as histiocytosis X, which is a potential differential diagnosis. Histopathologically, cells characteristically appear as spindle-shaped fibroblast cells with pale pink cytoplasm and elongated nuclei and the immunophenotype is defined with a positive reaction on smooth-muscle antigen vimentin and the muscle-specific antigen HHF-35. The data of the literature review underline that a wait-and-see-policy should be considered as the first treatment of choice as in most instances the bony lesions regress spontaneously. However, a thorough examination has to be carried out to exclude lesion in other organs like gastro-intestinal or cardio-pulmonary nodular tumor masses. In conclusion, the present case report and the literature review support the notion that infantile myofibromatosis should be considered as a possible differential diagnosis for soft tissue expansions and/or osteolytic lesions in a newborn.