Ear

External ear tumors - benign / nonneoplastic

Synovial chondromatosis of temporomandibular joint / external auditory canal



Topic Completed: 1 October 2013

Minor changes: 13 May 2021

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PubMed Search: Synovial chondromatosis of temporomandibular joint external auditory canal


Nat Pernick, M.D.
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Cite this page: Pernick N. Synovial chondromatosis of temporomandibular joint / external auditory canal. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/earsynovialchondromatosis.html. Accessed December 8th, 2021.
Definition / general
  • Also called synovial chondrometaplasia, synovial osteochondromatosis
  • Possibly neoplastic process in which multiple cartilaginous nodules form in synovium, some detach and float in joint space
  • Temporomandibular joint (TMJ) lesions cause asymptomatic mass of external auditory canal with preauricular swelling and limited joint motion (Arch Otolaryngol Head Neck Surg 1999;125:1394)
Radiology description
  • Numerous radiopaque loose bodies within TMJ but without bone destruction
  • Confined to joint space, usually easily enucleated
  • Rarely extends into parotid gland, temporal bone, cranium, auditory canal
Treatment
  • Conservative surgery
Gross description
  • Synovium with diffuse polypoid or pedunculated nodules, 1 mm to 3 cm, with smooth to granular external surface
Gross images

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Numerous nodules

Microscopic (histologic) description
  • Nodules of mature cartilage of varying cellularity within synovium and joint space
Differential diagnosis
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