Last Updated on January 31, 2025
Osteopoikilosis is a benign, autosomal dominant skeletal dysplasia that manifests radiographically as multiple bone islands, especially near the joints, epiphyses, and metaphyses of long and short tubular bones. The condition is also known as the spotted bone.
The condition itself is not symptomatic. Hence, it may be diagnosed incidentally during x-rays made for other reasons.
The male-to-female ratio is 3:2. The condition seems to appear in childhood and persists throughout life.
Osteopoikilosis has been reported more commonly in self-contained communities where consanguineous marriages are frequent.
It is mostly inherited as an autosomal dominant condition though sporadic cases can occur. Familial clustering suggests LEMD3 gene is responsible for the disease. The condition is featured by an abnormality in the enchondral bone maturation process. This leads to bone sclerosis that appears as dense spots on X-rays.
Histologically, the foci are formed by dense trabeculae of cancellous bone tissue, forming a nidus without communication with bone marrow.
Sites of Occurrence
Osteopoikilosis is more frequently found in the long bones and pelvis. The distribution is typically bilateral and symmetrical.
The lesions are rarely seen in the ribs, clavicles, spine, and skull.
Studies have reported the following sites to be commonly affected
- Phalanges of hand and foot
- Carpal bones
- Metacarpals and metatarsals
- Tarsal bones
- Pelvis
- Femur
- Radius
- Ulna
- Sacrum
- Humerus
- Tibia
- Fibula
Presentation of Osteopoikilosis
The condition is typically without symptoms. Therefore, it is usually discovered when x-rays or other imaging is done for some other reason. However, it is important to correctly diagnose it lest it is mistaken for some other condition.
Few studies have reported that slight joint pain and effusion may be seen in 15-20 percent of the patients. The mechanism of joint pain is not clear. The symptoms are without any deformity or dysfunction at the location site.
The pain may be due to irritation of the joint capsule or increased intraosseous pressure.
There are various associations of osteopoikilosis with various other conditions. These are
- Buschke-Ollendorff syndrome
- Dermatofibrosis lenticularis
- Synovial osteochondromatosi
- Keloid formation
- Scleroderma-like lesions
- Dacryocystitis
- Dwarfism
- Endocrine abnormalities
- Melorheostosis
- Cleft palate
Most patients have no other findings.
Imaging
On x-rays, the condition is seen as 2-10 mm round or oval shape densities that appear as dense radio-opaque spots in cancellous bone tissue [epiphysis and metaphyses] of long bones.
X-rays are often diagnostic. However, they may need to be differentiated from sclerotic bone metastases.
MRI may help in differential diagnoses in complicated cases. It shows as multiple circular or ovoid hypointense lesions
Bone scintigraphy usually does not show any tracer uptake in these persons.
Differential Diagnosis
Osteopoikilosis is quite rare but when present should raise a concern about other similar-looking differentials. These are generally
- Metastasis
- Tuberous sclerosis
- Paget’s disease
- Mastocytosis
- Osteopathia striata
- Mmelorheostosis
- Synovial chondromatosis
- Sesamoid ossicles
- Ollier’s disease
Out of these metastases are the most critical differential. These have been reported to be seen in about half of the patients considered to have osteopoikilosis.
In osteopoikilosis, the sclerotic lesions are symmetrical and present in bone epiphyses and metaphyse. These foci are uniform in size and never induce cortical erosion.
However, osteoblastic metastases may cause subcortical destruction. Moreover, alkaline and acid phosphatase are within normal range and bone scan is normal. The enzyme levels would be increased in metastases and there would be increased tracer uptake in case of bone scan.
Complications
The condition is benign and the complications are very rare. The reported possible complications are
- Osteosarcoma
- Giant cell tumor
- Chondrosarcoma
Treatment
Generally, no treatment is required. Being very rare, however, the entity should be kept as a differential diagnosis when encountered with multiple bony islands like picture. The symptomatic cases should be treated for the symptoms.
References
- Di Primio G. Benign spotted bones: a diagnostic dilemma. CMAJ. 2011;183:456–9. doi: 10.1503/cmaj.091740. [Link]
- 9.Benli IT, Akalin S, Boysan E, Mumcu EF, Ki? M, Türko?lu D. Epidemiological, clinical and radiological aspects of osteopoikilosis. J Bone Joint Surg Br. 1992;74:504–6. doi: 10.1302/0301-620X.74B4.1624505.
