8903/0 Fetal rhabdomyoma


Definitions

Connective, subcutaneous and other soft tissues
ICD-O-3 topography code: C49

Fetal rhabdomyoma (F-RM) is a rare benign mesenchymal neoplasm with immature skeletal muscle differentiation. More than 90% of F-RMs arise in soft tissue and mucosal sites of the head and neck region. The lesions are solitary, circumscribed, unencapsulated masses ranging in size from 1 to 12.5 cm. They are composed of immature spindle and polygonal cells in abundant myxoid stroma. The absence of prominent nuclear atypia is the most important criterion distinguishing F-RM from rhabdomyosarcoma1
 
Fletcher CDM, Unni KK, Mertens F (Eds.)
World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of Soft Tissue and Bone.
3rd Edition
IARC Press: Lyon 2002



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Fetal rhabdomyoma predominantly affects children (median age 4 years), but may also arise in adults. Males are more frequently affected (ratio 2.4:1). F-RM has repeatedly been observed in patients with nevoid basal cell carcinoma syndrome , which is associated with mutations in the tumour suppressor gene PTCH
2
Click to access Pubmed
Gorlin RJ (1995)
Nevoid basal cell carcinoma syndrome.
Dermatol Clin 13: 113-25



3
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DiSanto S, Abt AB, Boal DK, Krummel TM (1992)
Fetal rhabdomyoma and nevoid basal cell carcinoma syndrome.
Pediatr Pathol 12: 441-7



. The recommended treatment is complete surgical excision. Local recurrence is very rare, metastases have never been reported 4
 
Fletcher CDM, Unni KK, Mertens F (Eds.)
World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of Soft Tissue and Bone.
3rd Edition
IARC Press: Lyon 2002



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