Osteopoikilosis

Clinical History

A 35 year old woman was seen in the radiology department for suspected fractures due to trauma.

Imaging Findings

A 35 year old woman was seen in the radiology department for pain of the left knee after trauma.
The X-rays of the left knee revealed no acute bone injury however an abnormal appearance of the bones was noted, characterized by the presence of multiple, small, well defined, sclerotic bone lesions clustered in periarticular regions.
Was performed a plain X- ray of right knee even that detects the symmetry of bone lesions.
The radiographic diagnosis in this case is not difficult: the radiographic appearances are characteristic and sufficiently specific of hereditary benign and asymptomatic condition named osteopoikilosis. The study of other skeletal areas was not considered necessary so as not to expose a woman of childbearing age to ionizing radiation.
The patient was informed of the unusual result. His general practitioner prescribed a bone scan to exclude bone metastases, the result was normal

Discussion

Osteopoikilosis (osteopathia condensans disseminata, spotted bones) was first described by Stieda (1905) and subsequently by Albers-Schönberg and Ledoux-Lebard. It is a rare abnormality in the enchondral bone maturation process; generally transmitted in an autosomal dominant fashion in a which osteosclerotic dysplasia of bone develops during childhood and persists throughout life. Sporadic forms of osteopoikilosis have been reported.
The LEMD3 gene is responsible for this bone density disorder. Although the disorder is described as extremely rare, osteopoikilosis is probably more common.
The disorder is present both sex and may become evident at any age, although its appearance below the age of 3 years is distinctly uncommon.
Typically patients are asymptomatic although some may have mild articular pain and joint effusion. The diagnosis is usually made incidentally from X-ray performed for other reasons on the basis of distinctive radiographic appearances.
Characteristically, the radiographs detected multiple small well-defined densities a few millimetres in size. These lesions are symmetric and are clustered in the metaphyseal and subchondral regions, they appear in lines in the long axes of the long bones.
The most frequently involved areas are the epiphyses and metaphyses of long tubular bones and the carpi, tarsi, pelvis and scapulae. The ribs, skull and vertebrae are usually spared.
The radiopaque densities can increase or decrease in size and number or disappear. The dynamic nature of the lesions is more marked in children and adolescents than in adults.
Some patients, approximately 25 per cent of cases, have disseminated cutaneous lesions consisting of white spots on the skin called dermatofibrosis lenticularis disseminata.
This association is called Buschke-Ollendorff syndrome. In our case the patient not had skin lesions. Osteopoikilosis is also associated with a predisposition to keloid formation, dwarfism, spinal stenosis, dystocia, melorrheostosis, tuberous sclerosis and scleroderma.
Macroscopically the lesions appear as foci of compact bone within the cancellous. In the epiphyses of the tubular bones the foci rarely are in contact with the subchondral bone plate, whereas in the metaphyses they may be located eccentrically.
Histologically these sclerotic areas are focal condensations of compact lamellar bone within the spongiosa that form a nidus without communication with bone marrow.
The major differential diagnostic considerations are osteoblastic metastasis, mastocytosis, and tuberous sclerosis. The symmetrical distribution, the propensity for epiphyseal and metaphyseal involvement and the uniform size of the foci are suggestive of osteopoikilosis.
In mastocytosis and tuberous sclerosis, symmetry, metaphyseal and epiphyseal preference and uniformity are less defined than in osteopoikilosis.
Asymmetry, common involvement of the axial skeleton, including the spine, osseous destruction, variation in size and positive scintigraphic findings characterize skeletal metastases. The role of bone scan is controversial, some reports have emphasized the critical role of the bone scan for distinguishing osteopoikilosis from the osteoblastic bony metastases but there are a few reports of abnormal bone scan findings in osteopoikilosis among young patients.
In conclusion, the detection of cases of osteopoikilosis is simple but attention must be given to differential diagnosis in order to avoid misdiagnosis and unnecessary treatments.

Differential Diagnosis List

Final Diagnosis

Osteopoikilosis

URL:	https://www.eurorad.org/case/8473
DOI:	10.1594/EURORAD/CASE.8473
ISSN:	1563-4086