embryonal rhabdomyosarcoma
Pronunciation: em-bree-OH-nal RAB-doh-my-oh-sar-KOH-mah
The most common subtype of rhabdomyosarcoma in pediatric patients, typically affecting younger children and having a more favorable prognosis than alveolar variants.
Full Definition
Embryonal rhabdomyosarcoma represents approximately 70% of all rhabdomyosarcoma cases in children and is characterized by primitive mesenchymal cells that resemble developing skeletal muscle. This subtype commonly arises in the head and neck region, genitourinary tract, or retroperitoneum in children under 10 years of age. The tumor cells exhibit a spindle or round cell morphology with variable myogenic differentiation markers. Prognosis is generally more favorable compared to alveolar rhabdomyosarcoma, with 5-year survival rates exceeding 70% in many cases when treated with multimodal therapy including surgery, chemotherapy, and radiation therapy.
Usage
Usage note: Always specify subtype when discussing rhabdomyosarcoma to avoid confusion with alveolar variant, which has different treatment implications.
In Context
- "The pathology report confirmed embryonal rhabdomyosarcoma with favorable histologic features and negative margins." — Surgical pathology report
- "Unlike alveolar rhabdomyosarcoma, embryonal rhabdomyosarcoma rarely harbors PAX-FOXO1 fusion transcripts." — Molecular pathology summary