Muscle tumors Notes

NOTES NOTES MUSCLE TUMORS RHABDOMYOSARCOMA (RMS) osms.it/rhabdomyosarcoma PATHOLOGY & CAUSES ▪ Highly malignant tumor arising from skeletal muscle cells TYPES Alveolar Embrional ▪ Most common, frequently children ▫ Botryoid, spindle-cell rhabdomyosarcoma Pleomorphic (anaplastic) ▪ Worst outcome, frequently adults Figure 116.1 The histological appearance of a rhabdomyosarcoma, alveolar subtype. The cells are small, with little cytoplasm with bland chromatin structures visible. CAUSES ▪ Genetic translocation determining fusion of two genes which encode two transcription factors ▫ FOXO1, PAX3 ▪ FOXO1-PAX3 fusion protein interferes with differentiation-driven gene expression program → poorer outcome RISK FACTORS ▪ Syndromes, congenital anomalies (e.g. Li–Fraumeni syndrome, neurofibromatosis type I, Beckwith–Wiedemann syndrome, Costello syndrome) COMPLICATIONS Figure 116.2 The histological appearance of a rhabdomyosarcoma, embryonal subtype. The tumor is composed of numerous round or spindled cells, either with minimal or abundant eosinophilic cytoplasm. ▪ Metastasis ▪ Bone marrow involvement: anemia, thrombocytopenia, neutropenia OSMOSIS.ORG 677

TREATMENT SIGNS & SYMPTOMS ▪ Palpable mass ▫ Localization: head/neck, genitourinary tract, limbs, abdomen ▪ Depending on tumor size ▫ Hematuria, urinary obstruction (genitourinary tract involvement) ▫ Sinusitis, headache, cranial nerve alterations, ear discharge, orbital swelling (head involvement) MEDICATIONS ▪ Polychemotherapy ▪ Immunotherapy SURGERY ▪ Resection OTHER INTERVENTIONS ▪ Radiation therapy DIAGNOSIS DIAGNOSTIC IMAGING X-ray, CT scan, MRI, ultrasound ▪ Determines local invasion, metastasis LAB RESULTS ▪ Liver, renal function tests ▪ Complete blood count ▫ Anemia, pancytopenia ▪ Biopsy ▫ Microscopic analysis ▫ Immunohistochemical studies showing muscle tissue-characteristic proteins ▫ Genetic sequencing 678 OSMOSIS.ORG Figure 116.3 The gross pathological appearance of a rahbdomyosarcoma, embryonal subtype. The tumor is poorly circumscribed with a firm texture and is cream to white in color.