Rhabdomyoma



Rhabdomyoma


Cyril Fisher, MD, DSc, FRCPath









Hematoxylin & eosin shows adult rhabdomyoma composed of large polygonal cells with copious eosinophilic cytoplasm (varying in staining intensity) and small round nuclei with uniform nucleoli.






Hematoxylin & eosin shows fetal rhabdomyoma of myxoid (immature) type. Slender spindle cells form loosely organized fascicles in myxoid stroma. Note the absence of pleomorphism and necrosis.


TERMINOLOGY


Definitions



  • Benign tumor with skeletal muscle differentiation


  • Can arise in heart (cardiac rhabdomyoma) or extracardiac locations


  • Extracardiac tumors can be of adult or fetal histologic type


ETIOLOGY/PATHOGENESIS


Developmental Anomaly



  • No associations for most extracardiac lesions


  • Cardiac rhabdomyoma can be associated with tuberous sclerosis


  • Some fetal rhabdomyomas associated with nevoid basal cell syndrome



    • PTCH mutations



      • Inhibitory receptor in sonic hedgehog signaling pathway


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Rare


  • Age



    • Adults; mean: 6th-7th decades


    • Fetal rhabdomyoma mostly in childhood; median: 4 years



      • About 1/2 in 1st year or congenital


      • Rare examples in adults up to 6th decade


  • Gender



    • 75% in males


    • Genital rhabdomyoma mostly in middle-aged women



      • Rare cases in males


Site



  • Most often in head and neck region, especially fetal rhabdomyoma



    • Larynx, oropharynx, mouth, neck


  • Genital lesions mostly in vagina, occasionally vulva or cervix


  • Rare examples in males in paratesticular region or epididymis


Presentation



  • Incidental finding


  • Painless mass


  • Difficulty breathing


Treatment



  • Surgical approaches



    • Simple complete excision


Prognosis



  • Excellent after complete excision


  • Can recur if incompletely excised

Jul 9, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Rhabdomyoma
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