External ear tumors - benign / nonneoplastic
Atypical fibroxanthoma

Author: Nat Pernick, M.D. (see Authors page)

Revised: 23 February 2018, last major update October 2013

Copyright: (c) 2002-2018, PathologyOutlines.com, Inc.

PubMed Search: Atypical fibroxanthoma [title] ear

Cite this page: Pernick, N. Atypical fibroxanthoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/earafx.html. Accessed December 12th, 2018.
Definition / general
  • Also called superficial malignant fibrous histiocytoma
  • Usually sun damaged skin of elderly (75% in head and neck) or superficial soft tissue of extremities in young
Case reports
  • Excellent prognosis with complete excision
  • Local recurrence if incomplete excision
  • Probably cannot metastasize
  • May recur as large mass in deep soft tissue which should be treated as malignant fibrous histiocytoma (not superficial)
Gross description
  • Asymptomatic firm nodule, 1 - 2 cm, often with ulceration
Microscopic (histologic) description
  • Nonencapsulated but circumscribed spindle cell proliferation of dermis
  • Cells are spindled or pleomorphic with bizarre multinucleated forms or hyperchromasia
  • Cells may have foamy cytoplasm, increased mitotic figures including atypical forms
  • May have vascular invasion
  • No junctional activity, no necrosis
Positive stains
Negative stains
Differential diagnosis