Case Ten – October 2017

  • Patient Information
    • 66 year old male presented with a 1 cm papule on the scalp
  • Clinical Diagnosis
    • BCC
  • Histology

    Sections show nodular aggregates of basaloid cells in the dermis with cribriform architecture and pseuduoglandular spaces containing mucoid and eosinophilic material.

    Immunohistochemical stains performed with adequate controls show the basaloid cells are positive for SOX-10 and CD117 (C-KIT).

  • Final Diagnosis

    Adenoid cystic carcinoma

    • Adenoid cystic carcinoma is a rare cutaneous malignancy thought to arise from sweat glands
    • Primary cutaneous ACC most commonly presents on the scalp
    • Histologic features of ACC include nodular aggregates of basaloid cells with cribriform and tubular architecture, pseuduoglandular spaces containing mucoid and eosinophilic material, and frequent perineural invasion
    • ACC are positive for EMA, AE1/AE3, SOX-10, and CD117 (C-KIT) by immunohistochemistry. Myoepithelial cells often surround the basaloid aggregates and are highlighted using p63, SMA, calponin and S100 immunohistochemical stains.
    • Clinical correlation to exclude metastatic ACC from the salivary gland, breast, vulva, respiratory tract is important, since these tumors occur more frequently than primary cutaneous ACC
    • Treatment with wide local excision or Mohs micrographic surgery is usually curative
    • Cutaneous ACC have a better prognosis than salivary tumors
    • Distant spread of primary cutaneous ACC is rare, but local recurrence is more common due to frequent perineural involvement
  • Summary
    • Adenoid cystic carcinoma is a rare cutaneous malignancy thought to arise from sweat glands
    • Histologic features of ACC include nodular aggregates of basaloid cells with cribriform and tubular architecture, pseuduoglandular spaces containing mucoid and eosinophilic material, and frequent perineural invasion
    • ACC are positive for EMA, AE1/AE3, SOX-10, and CD117 (C-KIT) by immunohistochemistry.
    • Clinical correlation to exclude metastatic ACC from the salivary gland, breast, vulva, respiratory tract is important, since these tumors occur more frequently than primary cutaneous ACC
    • Treatment with wide local excision or Mohs micrographic surgery is usually curative
    • Local recurrence is common due to frequent perineural involvement