Older Woman with a Skin Lesion

Matthew R. Muenster, M.D.

Specimen Type:



65 year-old woman with a “tender, purple, growing” nodule of the left knee. “Glomus”

Pathologic Features:

The lesion consists of a very large and well-circumscribed nodule of large angular blood vessels set in a mass of homogenous, pink-spindled cells. The spindled cells have abundant cytoplasm, regular round-to-ovoid nuclei and regular nuclear contours.

Differential Diagnosis:

  • Angiosarcoma
  • Angioleiomyoma
  • Angioleiomyosarcoma
  • Deep hemangioma



A benign tumor composed of smooth muscle, angioleiomyoma, arises in skin from areas where smooth muscle is normally present. Typically, this is either the arrector pili muscle, vascular smooth muscle, or areola. Our case is rather typical as most angioleiomyoma occur in women with the lower extremity being predominant. The prominent vessels within give a purple-blue hue to the tumor and many are biopsied with the differential of “rule-out glomus tumor.” There is very little nuclear pleomorphism of the tumor and no definite mitoses were found further supporting this tumor as a benign one, rather than an angioleiomyosarcoma.


  1. Holst VA et al. “Cutaneous smooth muscle neoplasms: clinical features, histologic findings, and treatment options” .J Am Acad Dermatol. 2002 Apr;46(4):477-90; 491-4.
  2. Weedon D. Skin Pathology, 2nd ed. London, England, Churchill Livingstone, 2002.