The X-Files: February 2008

Marshall Deltoff
February 13, 2008
Written by Marshall Deltoff
xfiles1My sincere thanks to my dear friend, colleague and classmate, Dr. Howard Fisher of Toronto, for providing me with this case.

This 43-year-old woman presented with dull, achy sub-occipital pain, with decreased upper cervical ranges of motion.

The radiograph reveals a markedly enlarged posterior tubercle of atlas (5 cm in diameter), with abnormal internal trabeculation.

Diagnosis:  Osteoblastoma


– rare and benign; accounts for one per cent of all primary bone tumours
– originally described as an “osteogenic fibroma of bone” in 1956; shares similar clinical and histological features with osteoid osteoma, giant cell tumour and fibrous dysplasia
– commonly affects the vertebral column; 30 per cent in the posterior elements of the spine; also found in tubular bones
– bone-forming lesion (many immature bony trabeculae, lined with osteoblasts, demonstrating various degrees of ossification)
– may be cortical or medullary; when cortical, expansion is often present; may reach up to 11 cm in diameter!! (average 3.2 cm)
– may present with neurological symptoms as a result of cord or nerve root compression

– no helpful lab tests; biopsy required to confirm diagnosis

On X-ray:

– usually well-circumscribed cortical lesion, with thin shell of peripheral new bone
– lesion larger than 2 cm
– internally, displays varying degrees of radiolucency depending on amount of ossification of the numerous immature trabeculae
– may sometimes appear malignant, with adjacent cortical destruction and extraosseous soft tissue expansion
– CT is helpful in the management of the lesion, to provide accurate information regarding the size and extent of the lesion


– surgical resection; this is usually curative with good outcome

A 1983 CMCC graduate, Dr. Marshall Deltoff, DC, DACBR, FCCR(C), completed his radiology residency at Los Angeles College of Chiropractic. He is a past radiology department chairman and residency coordinator at CMCC, and he initiated the radiology curriculum at UQTR. Dr. Deltoff has lectured throughout North America, and is co-author, along with Dr. Peter Kogon, DACBR, of the radiology text “The Portable Skeletal X-ray Library” published by Mosby-Yearbook of St. Louis. Dr. Deltoff can be reached at:

Images Radiology Consultants,
16 York Mills Road, Toronto,
ON  M2P 2E5
Tel: (416) 512-2225 
Fax: (416) 512-2226 
e-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

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