Proliférations fibroblastiques et myofibroblastiques de l’enfance et de l’adolescence

Radiotherapy and long-term sequelae in pediatric patients with parameningeal rhabdomyosarcoma: Results of two Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry

BACKGROUND

Parameningeal location of rhabdomyosarcoma (PM RMS) is known to be an unfavorable prognostic factor. Scarce data are available on radiotherapy (RT) concepts with regard to outcome.

METHODS

Treatment and outcome of 395 children with PM RMS registered within two Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry (1995-2021) were evaluated.

RESULTS

Patients were IRS group II (n = 15) and III (n = 380) and received systemic treatment according to the enrolled protocols: I2VA (n = 172), VAIA/CEVAIE (n = 223). Delayed resection was performed in 88/395 (22%) patients, and RT was additionally given in 79/88 (90%) resected patients. RT was the predominant local treatment in 355/395 (90%) patients: hyperfractionated accelerated photon (HART; n = 77), conventionally fractionated photon (n = 91) or proton beam (n = 126), brachytherapy (n = 4), heavy ions (n = 1), not available (n = 56). In the subgroup of RT as only local treatment (n = 278), no intracranial tumor extension and complete remission at end of treatment were significant positive prognostic factors. No significant difference on tumor outcome was seen between different radiotherapy concepts. Long-term toxicity with mostly endocrinological and visual deficiencies was reported in 161/279 (58%) surviving patients with a lower trend after proton beam RT (48%) when compared to HART or conventionally fractionated photon RT (71% and 72%, respectively). Ten-year event-free and overall survival in the overall group were 62% (±5, 95% confidence interval [CI]) and 67% (±5, 95% CI); in the RT-only group 67% (±6, 95% CI) and 71% (±6, 95% CI), respectively.

CONCLUSION

CWS data confirm the recent RT concept in PM RMS. Long-term sequelae as endocrinological and visual deficiencies need to be addressed.

Infantile myofibromatosis: Excellent prognosis but also rare fatal progressive disease. Treatment results of five Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry

BACKGROUND

Infantile myofibromatosis (IM) is a rare benign soft tissue tumor and often a self-limiting disease but rarely includes life-threatening complications. Little is known about optimal treatment of primary localized (LD) and multifocal disease (MFD).

METHODS

Treatment and outcome of 95 children with IM registered within five Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry (1981-2016) were evaluated.

RESULTS

LD was diagnosed in 71 patients at a median age of 0.4 years (range 0.0-17.7). MFD was present in 24 patients. The mainstay of treatment was watch-and-wait strategy (w&w) after initial biopsy or resection. Low-dose chemotherapy (CHT) was administered to 16/71 (23%) patients with LD and eight of 24 (33%) patients with MFD, imatinib was added in two. A delayed resection was possible in eight of 71 (11%) and five of 24 (21%) patients with LD and MFD, respectively. Overall, patients were alive in complete remission (n = 77) and partial remission (n = 10) at a median follow-up time of 3.4 years after diagnosis (range 0.01-19.4); no data available (n = 5). Three patients died of progressive disease (PD) despite CHT. Gender, tumor size, and location correlated with a favorable event-free survival (EFS) in patients with LD. The 5-year EFS and overall survival of patients with LD were 73% (±12, confidence interval [CI] 95%) and 95% (±6, CI 95%), respectively; for MFD 51% (±22, CI 95%) and 95% (±10, CI 95%).

CONCLUSION

Prognosis is excellent in patients with LD and MFD. Targeted treatment needs to be evaluated for rare fatal PD.

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.

[Nodular fasciitis: case report and review of the literature]

Among soft tissue tumors, nodular fasciitis is a relatively common tumor process, which occurs in the 30 first years of life. Nodular fasciitis is a benign tumor with a rapid proliferation of myofibroblastic cells, which develops at the expense of a muscular fascia in the subcutaneous tissue. Usual localizations are the trunk and upper limbs. Difficulty of diagnosis consists in the need to eliminate many differential diagnoses especially malignant tumor processes. From a clinical point of view, the rapid development of nodular fasciitis (from some days to some weeks) must fear a malignant process. This benign lesion, which does not recur (even if incomplete resection), may regress spontaneously. We report such a tumor located at the cubital fossa confirmed by a pathological examination.

Risk-adapted therapy for infantile myofibromatosis in children

BACKGROUND

Infantile myofibromatosis is characterized by proliferation of benign fibrous tumors arising in skin, subcutaneous tissue, muscle, or bone. Solitary and multicentric forms are described. Few reports are available in the pediatric population.

PROCEDURE

To improve the knowledge of this rare tumor in infants, the authors present a series of all cases of infantile myofibromatosis treated in their institution over a 9-year period in order to propose treatment guidelines based on their experience and a review of the literature.

RESULTS

The authors report a series of 9 cases, 8 solitary forms and 1 multicentric form with visceral involvement treated from 2000 to 2009. Median age was 10 months (range: 2 days-14 years). Six patients with solitary forms underwent primary surgical resection leading to remission. Only biopsy was performed in 1 case, followed by tumor regression with no recurrence. The last patient with a solitary form was treated by chemotherapy and then surgery allowing remission. The patient with a multicentric form presented complete regression of tumors after 1 year of vinblastine and methotrexate combination chemotherapy.

CONCLUSIONS

Infantile myofibromatosis is a rare soft tissue tumor mainly concerning infants. Surgery is the treatment of choice for solitary forms when excision is possible. Close follow-up may be proposed in the case of inoperable sites. In multicentric life-threatening forms, chemotherapy promotes tumor regression and the vinblastine and methotrexate combination is effective with few long-term adverse effects.

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.