January 2018

  • Patient Information
    • 45 year old male presented with a painful mass on his hand.
  • Clinical Diagnosis
    • Ganglion cyst
    • Angiolipoma
    • Glomus tumor
  • Histology

    Sections show a nodular mass composed of ectatic blood vessels surrounded by sheets and aggregates of monotonous, darkly staining, epithelioid cells.

     

    The cells surrounding the blood vessels have smooth, round nuclei and inconspicuous nucleoli.

  • Final Diagnosis

    Glomus tumor

    • Glomus tumors are benign perivascular neoplasms arising from the Sucquet-Hoyer canal of the glomus body
      • The glomus body is a specialized arteriovenous anastomosis involved in thermoregulation
    • Glomus tumors commonly arise under the fingernail but may present at a variety of sites, including distal extremities, GI tract and head and neck area
      • Subungual glomus tumors are often extremely painful
    • Glomus tumors are composed of variably-dilated blood vessels surrounded by glomus cells in sheets and aggregates; the glomus cells are monotonous with round nuclei and inconspicuous nucleoli
    • Glomus cells are positive for smooth muscle actin by immunohistochemistry. CD34 can positive in a subset of cases
      • They are negative for desmin and S-100 by immunohistochemistry
    • Glomangiomyomas are tumors that show features of both a glomus tumor and angioleiomyoma
    • Glomangiomatosis is a variant of angiomatosis characterized by a benign vascular lesion affecting a large segment of the body that histologically shows increased glomus cells in association with abnormal blood vessels
    • Glomangiosarcoma is the malignant counterpart to glomus tumor and shows high grade cytologic atypia and increased mitotic activity (>5 mitotic figures/50 hpf)
  • Summary
    • Glomus tumors are benign neoplasms arising from modified smooth muscle cells of the glomus body
      • The glomus body is a specialized arteriovenous anastomosis involved in thermoregulation
    • Glomus tumors commonly arise under the fingernail but may present at a variety of sites, including distal extremities, GI tract and head and neck area
    • Glomus tumors are composed of variably-dilated blood vessels surrounded by glomus cells in sheets and aggregates; the glomus cells are monotonous with round nuclei and inconspicuous nucleoli
    • Glomus cells are positive for smooth muscle actin by immunohistochemistry