Ectopic ossification associated with osteoid osteoma in the acetabulum. A case report

Ectopic bone formation was associated with osteoid osteoma in the anterior rim of the acetabulum. A factor, which has been speculated to be secreted from the nidus and is responsible for increased osteoblastic activity, also seemed to have the capacity to stimulate young mesenchymal cells to differentiate into an osteogenic pathway. A case of a 35-year-old woman with osteoid osteoma, which caused ectopic ossification adjacent to the nidus, is presented.

Intra-articular osteoid osteoma of the humerus with synovitis simulating chronic monoarthritis of the elbow in a recreational tennis player

We present a case of intra-articular osteoid osteoma of the humerus simulating chronic monoarthritis of the elbow in an 18-year-old male right-handed recreational tennis player. CT revealed a well-defined nidus in the coronoid fossa. Microscopic examination of the synovium showed a lymphofollicular synovitis that resembled the synovitis in rheumatoid arthritis.

Osteoid osteoma of the upper extremity

Forty-six patients with histologically confirmed osteoid osteoma of the upper extremity seen from 1947 to 1990 were retrospectively reviewed. The patients' age at presentation averaged 20 years. Twenty-four of the lesions were located in the wrist and hand and 22 in the arm and forearm. The average duration of symptoms before diagnosis was 15 months. Pain was the presenting symptom in 44 of 46 patients. Of the 28 patients who took aspirin for pain, 24 obtained at least partial relief. A mass or swelling was more commonly noted in lesions of the hand and wrist as compared to the arm and forearm. The diagnosis of osteoid osteoma was made by plain x-ray films alone in 35 cases. Bone scans were performed on 13 patients; all were positive at the site of the lesion. Tomography was performed in 13 cases to identify the intraosseous location of the lesion. All lesions were treated by excision and curettage. Thirty-four of the 46 patients were followed at our institution for more than 6 months, with an average follow-up period of 27 months. Six of the patients had persistent lesions. Of the six persistent osteoid osteomas, five occurred in the wrist or hand (p = .0012). A total of 15 procedures were required to excise these lesions.

Benign bone-forming lesions: osteoma, osteoid osteoma, and osteoblastoma. Clinical, imaging, pathologic, and differential considerations

The benign bone lesions--osteoma, osteoid osteoma, and osteoblastoma--are characterized as bone-forming because tumor cells produce osteoid or mature bone. Osteoma is a slow-growing lesion most commonly seen in the paranasal sinuses and in the calvaria. When it occurs in the long bones, it is invariably juxtacortical and may need to be differentiated from, among others, parosteal osteosarcoma, sessile osteochondroma, and a matured juxtacortical focus of myositis ossificans. Osteoid osteoma and osteoblastoma appear histologically very similar. Their clinical presentations and distribution in the skeleton, however, are distinct: osteoid osteoma is usually accompanied by nocturnal pain promptly relieved by salicylates; osteoblastoma arises predominantly in the axial skeleton, spinal lesions constituting one-third of reported cases. This review focuses on the application of the various imaging modalities in the diagnosis, differential diagnosis, and evaluation of these lesions. Their histopathology also is discussed, and their treatment briefly outlined.

Case report 801: Osteoid osteoma of the coccyx

In summary, a typical osteoid osteoma in the coccyx in a 13-year-old boy has been presented-a unique location. The clinical, radiological, and pathological aspects of osteoma are summarized. The relationship of osteoid osteoma to osteoblastoma is stressed; it is also stressed that the occurrence of osteoid osteoma in the coccyx is most unusual.

Unbalanced translocation resulting in the loss of the chromosome 17 short arm in an osteoblastoma

We report results of the first cytogenetic study of an osteoblastoma. Cells from the tumor were characterized by a three-way unbalanced translocation involving chromosomes 15, 17, and 20. As a consequence of the translocation, most of one chromosome 17 short arm appears to have been lost. This loss suggests the possibility that loss of 17p DNA sequences may be involved in early changes leading to neoplastic proliferation of osteoblasts.

Osteoid osteoma of the hamate: report of a case and review of the literature

There are 7 reported patients with osteoid osteoma of the hamate. Only 1 of these has involved the hook of the hamate. This article reports the second patient with osteoid osteoma involving the hook of the hamate. The clinical features, the diagnostic problems, and the management of this lesion are reviewed.

[The morphological diagnosis of osteoblastoma in children from the viewpoint of its early oncological pathology]

A multifactorial morphologic study was performed in 72 children (49 boys and 23 girls) aged from 2 to 16 years, operated on because of osteoid osteoma and osteoblastoma of 12 anatomical sites. It is shown that different variants of early stages of osteogenic tumours correspond to different levels of cell differentiation and atypia. The smallest foci of dysplasia found near the tumour should be considered as pretumorous bone dysplasia.

Mechanism of pain in osteoid osteomas: an immunohistochemical study

Osteoid osteoma is a benign bone tumour characterized by pain which is relieved by non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin. To clarify the mechanism of the pain, five osteoid osteomas were studied immunohistochemically using polyclonal antibodies against prostaglandin E2 (PGE2), S-100 protein and protein gene product 9.5 (PGP 9.5). In all five cases, the pain had been relieved by NSAIDs. Nerve fibres positive for S-100 protein and PGP 9.5 were observed in the fibrous zone, especially close to the blood vessels, around the nidus in all the lesions and also within the nidus in three lesions. PGE2 immunoreactivity was variably positive in the nidus of three lesions. In one case a large number of actively proliferating osteoblasts reacted with this antibody. The other cases showed unevenly distributed PGE2 positivity which tended to be prominent in the plump osteoblasts. As control material we examined fibrous dysplasia (3 cases), osteosarcomas (3) and giant-cell tumours of bone (3). The plump osteoblastic tumour cells of three osteosarcomas and the bone-forming cells in two cases of fibrous dysplasia gave a positive reaction for PGE2. No S-100 or PGP 9.5 immunoreactive nerve fibres were seen in these lesions. It is concluded that the presence of nerve fibres alone might play a more important role in mediation of pain in osteoid osteomas than some effects of osteoblast-produced PGE2 on the nerves and proliferated blood vessels.

Osteoblastoma and osteoid osteoma. Clinical and morphological features of 162 cases

A study of 46 osteoblastomas and 91 osteoid osteomas, selected from a total of 162 cases proceeding from 15 Spanish Hospitals was done to establish epidemiological data on clinico-pathological parameters and to compare them with the findings of other authors. A comparative study between both tumors is done and emphasis is put on the discussion of aggressive osteoblastoma.

Aggressive osteoblastoma of the calcaneus

Aggressive osteoblastoma of the left calcaneus in 29-year-old Japanese woman is reported. Her initial symptom was heel pain while walking. This was a primary calcaneal tumor, initially diagnosed as a benign osteoblastoma. After a 5-year follow-up (from the initial curettage), there was local recurrence. The histologic findings of aggressive osteoblastoma were confirmed after right lower leg amputation. The recurrent tumor was mildly aggressive to the talocalcanean joint and the retrocalcaneal area, without distant metastasis. The characteristics of the primary and recurrent tumors were examined by the radiologic, histologic, and electron microscopic procedures. Although there are questions about aggressive osteoblastoma, the authors believe that there are osteoblastic tumors of borderline malignancy between benign osteoblastoma and low-grade osteosarcoma. The current case was an example compatible with an aggressive osteoblastoma with the proposed name of Dorfman classification Group 4.

Osteoblastoma with cartilaginous matrix. An unusual morphologic presentation in 18 cases

By definition, the occurrence of cartilaginous matrix in a bone-forming tumor eliminates the diagnosis of osteoblastoma and suggests a possible diagnosis of osteosarcoma. However, this rule is not absolute, as demonstrated by 18 cases of osteoblastoma that produced cartilaginous matrix. Hyaline cartilage was detected in four cases, and chondro-osteoid material was detected in 14 cases. In all patients, the tumor was in the appropriate patient age range and location for an osteoblastoma. The radiographic features as well as the histology, with the exception of the cartilaginous components, were in keeping with diagnosis of osteoblastoma. Intralesional excision (curettage or debulking) was performed in 13 patients and wide resection in five patients. Persistent tumor in one patient required a further intralesional excision. There were four recurrences, and no metastases were reported after follow-up of 1 to 23 years. The presence of cartilaginous matrix in a bone-forming lesion does not exclude the diagnosis of osteoblastoma and, more importantly, it is not always an indication that the tumor is an osteosarcoma.

[Magnetic resonance imaging in osteoid osteoma]

The purpose of this study was to determine magnetic resonance imaging (MRI) features of osteoid osteomas and to evaluate the place of MRI in the diagnostic workup of suspected osteoid osteoma by comparing its diagnostic value with that of computed tomography (CT). Nine patients with radioclinical features highly suggestive of osteoid osteoma were investigated using bone scintigraphy, CT scan and MRI. MRI sequences were weighted for T1 (TR: 500 ms-TE: 34 ms), T2 (TR:2000 ms-TE:50-100 ms) and T1 after intravenous injection of gadolinium-DTPA contrast material. The appearance of the nidus and surrounding area were analyzed, as well as the accompanying inflammatory reaction involving the bone marrow, soft tissues or synovium. All patients had surgical treatment. Clinical recovery was achieved in every case. Histological studies confirmed the diagnosis of osteoid osteoma in 7 patients. In two cases, histological confirmation was not obtained and the exact nature of the lesion therefore remained in doubt, although clinical and scintigraphic findings as well as the subsequent course were consistent with the diagnosis of osteoid osteoma. In 5 cases, MRI proved inferior to CT scan for detecting the nidus. MRI disclosed edema of the bone marrow not seen on CT scan sections in 5 cases, edema of the soft tissues in three cases, and synovitis with joint effusion in one patient with an epiphyseal osteoid osteoma. At present, MRI plays only an ancillary role in the diagnosis of osteoid osteoma, which rests on the concomitant use of bone scintigraphy and CT scan.(ABSTRACT TRUNCATED AT 250 WORDS)

Reactive soft-tissue mass associated with osteoid osteoma: correlation of MR imaging features with pathologic findings

The authors retrospectively reviewed three cases of histologically documented osteoid osteoma in which magnetic resonance (MR) imaging was performed prior to surgical excision. In all three cases, MR imaging demonstrated abnormal signal intensity characteristics, and use of gadopentetate dimeglumine resulted in enhancement. These findings correlated with a reactive soft-tissue mass with myxomatous change, as well as with cell-depleted, juxtanidal bone marrow that contained proteinaceous material. These MR imaging findings can easily be confused with those of a malignant tumor or osteomyelitis.

Evaluation of osteonectin as a diagnostic marker of osteogenic bone tumors

Osteonectin (ON), a 32,000-kd glycoprotein involved in the early steps of mineralization of skeletal tissue, is a recognized differentiation marker of normal osteogenic cells. The expression of ON was evaluated in vitro and in tissue sections by the polyclonal antibody bON II. In different cell cultures immunocytochemistry and molecular biology displayed a nonspecific reaction for the antibody, which showed itself to be useless for the in vitro identification of cells of the osteoblastic lineage. The diagnostic use of bON II antibody was investigated by immunohistochemistry on a series of osteogenic and nonosteogenic bone tumors. A strongly positive stain of the entire neoplastic component of osteosarcoma and osteoblastoma and a weaker stain of the mononuclear component of giant cell tumor and chondroblastoma were observed. On the other hand, stains for chondrosarcoma, Ewing's sarcoma, fibrosarcoma, malignant fibrous histiocytoma, and brown tumor from hyperparathyroidism were entirely negative. Our results indicate that ON may be helpful in the histologic diagnosis of bone tumors, particularly in differentiating small cell osteosarcoma from other small round cell tumors.

[Osteoblastoma in the iliac crest]

An 18 year old male patient is reported with a five year history of mild pain in his right hip. Radiological investigation showed a typical feature for osteoblastoma of iliac bone, with two niduses. En bloc excision was performed. The histological examination's result was also osteoblastoma.

Misleading aggressive MR imaging appearance of some benign musculoskeletal lesions

After plain radiography has been performed, magnetic resonance (MR) imaging is considered the modality of choice for the evaluation of suspected musculoskeletal lesions because of its exquisite sensitivity to changes in the signal intensity of marrow and soft tissue. That sensitivity, however, may lead to an overestimation of the aggressiveness and extent of some benign bone lesions, particularly in children. Such lesions include chondroblastoma, osteoid osteoma, eosinophilic granuloma, and stress fractures. Potentially misleading MR features commonly seen include prominent marrow edema, soft-tissue edema, and apparent mass effect adjacent to the bone lesion. Features that these lesions have in common that may explain the MR findings include associated inflammatory reactions caused by the lesions and their occurrence in childhood, when the periosteum is more loosely attached. Knowledge of the potential pitfalls encountered with MR imaging may help explain the discrepancy between the radiographic and MR appearances of these benign lesions and avoid misplaced reliance on MR imaging for a diagnosis. Radiography remains the single most valuable modality in determining a differential diagnosis for bone lesions.

Cementoblastoma and osteoblastoma: a comparison of histologic features

Three cases of cementoblastoma (CB) and three cases of osteoblastoma (OB) were histologically compared. The aim of the study was to investigate whether CB and OB are different in other aspects than being connected with a tooth. CB cases were the following: maxillary lesions in a 23-year-old woman and a 22-yr-old man and a mandibular lesion in a 28-yr-old man. In one case the tumor was fused to the roots of two teeth. Of the OB cases, one occurred in the mandible of a 27-yr-old man, one in the ankle of a 19-yr-old male and one in the thoracic vertebrae of a 27-yr-old man. Histologically, CB and OB had the same appearance including peripheral spiculae rimmed by swollen blasts. This histologic similarity between OB and CB indicates that the diagnosis CB should not be made unless the lesion is connected with a tooth.