|Year : 2012 | Volume
| Issue : 2 | Page : 147-150
Osteoblastoma of radius
Soma Datta1, Soumya Ghosh2, Arunima Chaudhuri3, Bikash C Mondal2
1 Department of Pathology, BMCH, Burdwan, India
2 Department of Orthopaedics, BMCH, Burdwan, India
3 Department of Physiology, Dr. D. Y. Patil Medical College, Pune, India
|Date of Web Publication||10-Nov-2012|
Krishnasayar South, Borehat, Burdwan-713102, West Bengal
Source of Support: None, Conflict of Interest: None
An 18-year-old male presented with a huge swelling in his left forearm, which was progressively increasing for four years with episodic pain in the outpatient department of Burdwan Medical College and Hospital, Burdwan. Investigations and clinical examinations were done that revealed the swelling to be a bony tumor. The patient was operated upon with en bloc removal of tumor and the site replaced by bone graft. Preoperative fine needle aspiration cytology showed the tumor to be a giant cell containing lesion of bone reported as osteoblastoma, a benign bone-forming tumor on histopathological evaluation. Postoperative follow-up of the patient showed good response with complete union of bone graft and full range of joint movement.
Keywords: Bone graft, giant cell, osteoblast, osteoid
|How to cite this article:|
Datta S, Ghosh S, Chaudhuri A, Mondal BC. Osteoblastoma of radius. Med J DY Patil Univ 2012;5:147-50
| Introduction|| |
Osteoblastoma is a rare primary neoplasm of bone, categorized as a benign bone-forming tumor that usually occurs in spine and long bones of young adults. Osteoblastoma and osteoid osteoma are histologically very similar but they differ in presentation, localization, radiographic appearance, treatment and recurrence. Osteoblastomas are larger than osteoid osteomas and involve spine more frequently. Pain is dull, achy and unresponsive to salicylates and does not induce marked bony reaction. An aggressive type of osteoblastoma has been described that has characteristics similar to that of osteosarcoma. ,,
Osteoblastoma accounts for 0.5% to 2% of all primary bone tumors. The tumor most commonly occurs in the dorsal aspect of vertebrae, metaphysis or diaphysis of long bones, and rarely in pelvis. In the spine, tumor is usually located in posterior processes, while vertebral bodies are spared. Tumor frequency is lower in thoracic spine and greater and equal occurrence in cervical and lumbar regions. Osteoblastoma predominantly affects young adults. Peak age of incidence is approximately 20 years, though the tumor may present as early as 10 years to as late as 60 years. Males exceed females in a ratio of 2-3:1. ,,,
| Case Report|| |
An 18-year-old male patient attended the Outpatient Department of Orthopaedics in Burdwan Medical College, Burdwan (West Bengal). The patient was having a huge swelling on his left forearm, which was well appreciated on anterior position and was progressively increasing in size. Initially, it was painless but episodic pain used to be felt due to infliction of secondary trauma. Clinically, it was a well-defined hard, bony, non-tender swelling. Range of joint movements (elbow and wrist) was normal [Figure 1].
The patient was advised radiologic (X-ray), hematological and biochemical investigation. Fine needle aspiration cytology (FNAC) was done from the swelling using an 18-gauge needle. X-ray of the swelling showed a huge, well-defined, radiolucent lesion involving radius bone of left forearm, showing soap bubble appearance at places [Figure 2].
FNAC revealed spindle cells, osteoclasts, osteoblasts and a pinkish osteoid-like material, and cytological study reported a benign bone-forming lesion of bone.
Two surgical teams were present: one for upper limb operation and the other for harvesting fibular graft from left lower limb. This shortened the tourniquet time.
Operation was performed under general anesthesia. Surgical approach was through anterior approach of the forearm. An incision was given extending from 2″ above the wrist joint to 2″ below the elbow. After separating the subcutaneous tissue and fascia between the planes of brachioradialis and fusiform tumor of 5″ × 3″ extending from 3″ above lower end of radius up to 2″ below radial tuberosity. After the separation of the vessels and nerves, wide excision of tumor was done [Figure 3]. Under tourniquet, a long segment (6″) of fibula was harvested through a minimally invasive double incision technique from left lower limb, which was placed in the place of resected left radius and fixed with an intramedullary rush nail from radial styloid up to the head of radius [Figure 4]. Finally, the wound was closed in layers after applying the suction drain and a POP backslab was applied thereafter. ,,
The resected tumor was sent for pathological examination. A fusiform mass was found with attached segments of resected bone measuring 6″ with the tumor measuring 5″ × 3″. External surface was hard and smooth. Cut surface showed cheesy material. No necrotic areas were found. On microscopy, sections showed anastomosing bony trabeculae with prominent rimming of osteoblasts in trabecular arrangement with osteoid tissue and numerous multinucleated osteoclastic giant cells. The cells showed insignificant mitotic activity and minimal cellular atypia. The intertrabecular spaces were arranged loosely and contained occasional spindle cells and capillaries. Few foci showed secondary changes like aneurysm bone cyst resembling features. The tumor was diagnosed as OSTEOBLASTOMA [Figure 5]. ,,
After two weeks of operation, stitches were removed in the upper and lower limb followed by application of POP cast to left upper limb, which was further kept for 10 weeks. After removal of the cast, left forearm molded guard was applied and kept for another five months, which was removed accordingly for wrist and elbow joint movement. X-rays were taken at intervals of six weeks. Then, fibula was incorporated (complete union) at upper and lower ends of resected radius after about eight months of operation with no neurological deficit in left upper limb [Figure 6] and [Figure 7]. ,
| Discussion|| |
The clinical course of osteoblastoma often makes it difficult to diagnose. The tumor may have a slow indolent course or display characteristics that are confused with malignancy. Other diagnoses that share similar clinical, radiographic and histological features with conventional osteoblastoma include osteoid osteoma, giant cell tumor and fibrous dysplasia. Osteoblastomas may also have features that mimic malignant tumors such as osteosarcoma. Osteoblastoma is about 20 times less common than osteosarcoma. ,,,
Osteoblastomas may be found within the cortex, medullary canal or periosteal tissues. Multi-centric foci within a single bone have also been described. There is a slight predominance of metaphyseal over diaphyseal lesions, with very few lesions reported in epiphyseal location. ,
According to the musculoskeletal society tumor staging (MSTS) system of benign bone tumors, most osteoblastomas are stage II lesions. Stage II lesions are characterized by benign cytologic characteristics, remain intracapsular and do not metastasize. While stage III osteoblastomas destroy bone much more aggressively and extend extracapsularly, histologic architecture and cell structure remain benign. ,,
The nomenclature for aggressive osteoblastoma has been controversial. Despite lack of recognized metastasis, debate continues regarding whether to classify it as a malignant osteoblastoma or an osteoblastoma-like osteosarcoma. Lucas reported that "distinguishing osteoblastoma from osteosarcoma is one of most challenging and important problems in orthopedic pathology and is sometimes impossible." The histological diagnosis requires a meticulous microscopic examination for cellular atypia, nuclear atypia, abnormal mitosis and penetrating pattern. If any of these characteristics are found, osteosarcoma could be considered likely diagnostic. Tumor cells for osteoblastoma may show different reactivity pattern for expression of cyclooxygenase 2 than atypical cells in osteosarcoma. ,
Radiation therapy or chemotherapy to treat osteoblastoma is controversial. Many authors believe that neither treatment has any therapeutic effect on this lesion. Post-irradiation sarcoma has been reported in the management of benign tumors, which makes this method of treatment inappropriate for benign, surgically accessible tumors. The appropriate surgical treatment goal for osteoblastoma is complete excision of the lesion. For stage I and II lesions, recommended treatment is extensive intralesional curettage. A high speed burr is usually used to remove gross and microscopic tumor, as well as a circumferential margin of normal bony tissue. For stage III lesions, wide resection is recommended to ensure removal of all tumor-bearing tissue, which is excision of tumor with circumferential cuff of normal bone and soft tissue around entity and is considered as curative for osteoblastoma, which is done in our case of osteoblastoma of radial bone. ,,
In a study of 99 cases of osteoblastoma over 30 years (1974-2006), local recurrence rate was 24% following curettage and packing. Recurrence however can be minimized by resective surgery. Regardless of the method of resection, surgical specimen margins must be tumor-free to ensure complete excision of the tumor. Osteoblastomas have a reported recurrence rate of approximately 10%-20%. Tumor relapse is associated with inadequate resection of initial lesion. However, in some areas, like spine, it might not always be possible to remove the entire lesion. The recurrence rate for stage II osteoblastoma after an extensive intralesional excision is close to 0%, whereas the recurrence rate after excision through reactive zone of bone (marginal excision) is much higher. For stage III osteoblastoma, recurrence rate after wide excision of surgically accessible sites is negligible. The recurrence rate after intralesional excision is higher at any sites, as would be expected. ,,, In the present case, due to the large size of the tumor and periosteal nature involving a long segment of radius, decision of wide excision of the lesion and replacement of lost segment by fibular graft is considered wise enough, which can lower the rate of recurrence.
Diagnosis and treatment of osteoblastoma require the coordinated participation of a radiologist, pathologist and orthopedic surgeon with expertise in orthopedic oncology. Once diagnosis is made, outcome is generally good. Keeping in view of the location of tumor, size, progress and cytological morphology or malignant potential, the schedule of surgical intervention must be taken into account for a procedure free of complications like bleeding, infections and lowering the future recurrence possibility.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]