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.



  • 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


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



  • 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


  • 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


  • Incidental finding

  • Painless mass

  • Difficulty breathing


  • Surgical approaches

    • Simple complete excision


  • 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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