Bone
Bone forming tumors (not osteosarcoma)
Osteoid osteoma

Author: David Lucas, M.D. (see Authors page)

Revised: 26 October 2016, last major update August 2013

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: Osteoid osteoma[title]
Cite this page: Osteoid osteoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/boneosteoidosteoma.html. Accessed December 11th, 2016.
Definition / General
  • Small, benign, bone forming tumor associated with pain and limited growth potential
  • Nidus < 1.5 cm (any larger size arbitrarily considered to be an osteoblastoma)
Epidemiology
  • Children, adolescents and young adults (most patients 5 - 24 years old)
  • Male:female ratio 3:1
Sites
  • Long bones, especially femur and tibia (50%) most common
  • Virtually any bone can be affected
Pathophysiology
Clinical Features
  • Intense localized pain, worse at night, relieved by NSAIDs
  • Juxta - articular tumors with arthritis or joint dysfunction
  • Vertebral tumors with scoliosis
Diagnosis
  • Intense pain and classic radiographic features
Radiology Description
  • Nidus usually < 1 cm
  • Nidus may be radiolucent or ossified and surrounded by a radiolucent halo
  • Usually surrounded by dense, reactive osteosclerosis
  • Intracortical, subcortical, medullary or bone surface locations
  • Long bone tumors often intracortical
  • Vertebral tumors in neural arch
Prognostic Factors
  • Recurrence is rare
  • Incompletely excised tumors can recur
Case Reports
Treatment
Radiology Images

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Phalanx

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Femoral neck

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Femur - contributed by Dr. Mark R. Wick

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Contributed by Dr. Mark R. Wick

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Talus - contributed by Dr. Mark R. Wick



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Intracortical osteoid osteoma of tibia

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Femur; coronal CT scan shows a radiolucent nidus

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Transverse process of vertebra with ossified nidus and radiolucent halo

Gross Description
  • Small circumscribed nidus with surrounding sclerosis (intact specimen)
  • Most often received as red, gritty fragments post curettage
Gross Images

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Femur

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Femur - contributed by Dr. Mark R. Wick

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Contributed by Dr. Mark R. Wick



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Nidus and surrounding sclerosis



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Fibula

Micro Description
  • Small, circumscribed
  • Anastomosing, irregular trabeculae or solid, sclerotic nidus of woven bone with variable mineralization
  • Rimmed by single layer of osteoblasts plus frequent osteoclasts
  • Loose, fibrovascular stroma
  • Surrounded by thick sclerotic bone
  • Lymphoplasmacytic synovitis with juxta - articular tumors
Micro Images

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Foot - contributed by Dr. Mark R. Wick

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Contributed by Dr. Mark R. Wick


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Vascular, loosely fibrous stroma

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Mature osteoid osteoma

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Irregular bony trabeculae

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Synovitis

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Femur



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With anastomosing trabeculae of woven bone

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High power

Molecular / Cytogenetics Description
Differential Diagnosis