Infantile Myofibroma

Anamnèse

Ten-year-old boy with subcutaneous mass of the anterior chest wall. Possible trauma.

Résultats

Anterior  left chest wall FDG-avid mass (SUV max 9.0), homogenenous on both PET and  CT.  Well circumscribed lesion measuring 18 x 10 x 15 mm. No calcifications. No chest wall transgression.

No other FDG-avid lesion.

The lesion was surgically removed.

Diag. Diff.

Myositis ossificans

Rhabomyosarcoma

Ewing’s family of tumors

Extraskeletal osteosarcoma

Abcess

Hematoma

Inflammatory pseudo-tumor

Myofibroblastic neoplasm

Metastasis

Discussion

Diagnosis

Infantile Myofibroma

Discussion

The myofibromatous tumors either solitary (myofibroma) or multiple (myofibromatosis) are fibroblastic-myofibroblatic lesions mostly encountered in chidren.  In a serie of 42 children, median age at presentation was 36 months and two thirds were male . The head and neck region was affected in half and lesions were solitary in 90% of cases. Treatment is surgical. In rare cases of generalized disease, chemotherapy may be needed.

Pathology findings was a well defined  encapsulated lesion containing fusiform cells,  myxoid fascicles  and "hemangiopericytic" vessels   with anti CD34 positivity.  There was diffuse positivity for anti-actin smooth muscle and negativity for Cytokeratine EA1/EA3,Desmin,Myogenin and S100 protein.

Positivity on F18-FDG PET/CT has been reported in two cases of adult mandibular solitary myofibroma. Both showed rapid but painless  growth, suggestive of a more aggressive process. In one patient SUVmax was 14.1. Differential diagnosis includes benign and malignant spindle cell tumors. A rare case of muscular myofibroma was also reported in a 46-year-old with a SUVmax of 13.6

Références

References

• http://www.pathologyoutlines.com/topic/softtissuemyofibroma.html

• Myofibroma in Infancy and Childhood. P Mahajan, J Hicks, M Chintagumpala, R Venkatramani. J Ped Hematol Oncol 2017;39:e136-e139

• Solitary myofibroma of the mandible in an adult with magnetic resonance imaging and positron emission tomography findings: a case report. Y Tanaka, H Yamada, T Saito, K Nakaoka, K Kumagai,H Fujihara, K Mishima, Y Hamada. World J Surg Oncol 2014;12:69-75

• Rapid Growing Myofibroma of the Gingiva: report of a case and review of the literature. M Aki, H Yoshimura, S Ohba, S Kimura, Y Imamura, K Sano. J  Oral Maxillofac Surg 2014;72:99-105

• Myofibroma of the left supraspinous muscle on F18-FDG PET/CT. N Fang, YL Wang, L Zeng, ZJ Wu, ZJ Cui. Clin Nucl Med 2016;41:317-318