External ear tumors - benign / nonneoplastic

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: Myxoma [title] ear

Cite this page: Pernick, N. Myxoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/earmyxoma.html. Accessed October 17th, 2018.
Definition / general
  • May arise as part of Carney complex (Semin Dermatol 1995;14:90)
  • Carney complex: autosomal dominant disorder with multiple cardiac and skin myxomas, spotty pigmentation of skin, endocrine overactivity (pigmented nodular adrenocortical disease, large cell calcifying Sertoli cell tumor of the testis, pituitary adenoma), blue nevi, psammomatous melanotic schwannoma, bone tumors (Am J Surg Pathol 1994;18:274)
Case reports
  • Excision
  • Usually don't recur
Gross description
  • Mucoid, 3 mm to 2 cm
Microscopic (histologic) description
  • Circumscribed but nonencapsulated hypocellular tumor with minimal blood vessels, composed of mucoid material with suspension of loose framework of reticulin fibers
  • Cells are spindled with tiny pyknotic nuclei and delicate cytoplasmic processes
  • May have pseudocapsule of condensed reticulin fibers and compressed skeletal muscle
  • No pleomorphism
Microscopic (histologic) images

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Positive stains
Negative stains
Differential diagnosis
  • Myxoid change in neurofibroma, schwannoma or lipoma
  • Sarcomas: more cellular, more vascular, atypia, mitotic figures