May 2018

  • Patient Information
    • 51 year old male presented with hard 5 cm mass on his upper back.
  • Clinical Diagnosis
    • DFSP
    • Melanoma
    • Sarcoma
  • Histology

    Sections show a poorly-defined, cellular dermal spindle cell neoplasm arranged in fascicles.

      

    Higher magnification shows the tumor cells have nuclei with blunt ends, eosinophilic cytoplasm and perinuclear vacuoles. Cytologic atypia and mitotic figures are identified.

  • Final Diagnosis

    Cutaneous leiomyosarcoma

    • Cutaneous leiomyosarcoma is a rare tumor that is believed to arise for the arrector pili muscle or dartos muscle in the scrotum
    • These tumors most often arise in men with a mean age of 40-60 years
    • Common primary sites include the head and neck, extremities and scrotum
    • Tumors are usually based within the dermis but extension into the subcutaneous tissue can be seen
      • Cutaneous leiomyosarcomas limited to dermis are sometimes referred to as “atypical leiomyoma” to emphasize their benign clinical course
      • Tumors with subcutaneous extension have a higher likelihood of local recurrence and metastasis
      • Tumors with metastases often involve the lung
    • Histologic features of cutaneous leiomyosarcomas include bundles and fascicles of eosinophilic tumor cells with ovoid to blunt ended nuclei. Nuclear pleomorphism and mitotic activity are also conspicuous.
    • Leiomyosarcomas are positive for smooth muscle actin (SMA), muscle-specific actin, caldesmon and desmin by immunohistochemistry in most cases
    • Wide local excision is the preferred management approach to prevent local recurrence

     

  • Summary
    • Cutaneous leiomyosarcoma is a rare tumor that is believed to arise for the arrector pili muscle or dartos muscle in the scrotum
    • Tumors are usually based within the dermis but extension into the subcutaneous tissue can be seen
      • Cutaneous leiomyosarcomas limited to dermis are sometimes referred to as “atypical leiomyoma” to emphasize their benign clinical course
      • Tumors with subcutaneous extension have a higher likelihood of local recurrence and metastasis
    • Histologic features of cutaneous leiomyosarcomas include bundles and fascicles of eosinophilic tumor cells with ovoid to blunt ended nuclei. Increased cellularity, nuclear pleomorphism and mitotic activity are also conspicuous.
    • Leiomyosarcomas are positive for smooth muscle actin (SMA), muscle-specific actin, caldesmon and desmin by immunohistochemistry in most cases
    • Wide local excision is the preferred management approach to prevent local recurrence