Table 2.
Definitive histological diagnosis and corresponding tentative radiological diagnoses
| Definitive diagnosis | n (total) | Tentative radiological diagnosis (n) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Aneurysmatic bone cyst | Ewing’s sarcoma | Intraosseous lipoma | Metastasis | Other/multiplea | Simple bone cyst | Osteosarcoma | Lymphoma | ND | ||
| Aneurysmatic bone cyst | 11 | 7 | – | 1 | – | 1 | 2 | – | – | – |
| Ewing’s sarcoma | 5 | – | 3 | – | – | 2 | – | – | – | – |
| Intraosseous lipoma | 12 | – | – | 6 | – | – | 6 | – | – | – |
| Metastasis | 4 | – | – | – | 3 | 1 | – | – | – | – |
| Other (osteonecrosis and osteomyelitis) | 26 | 3 | – | 2 | 1 | 13 | 7 | – | – | – |
| Simple bone cyst | 26 | 3 | – | 1 | – | – | 22 | – | – | – |
| Osteosarcoma | 7 | 1 | – | – | – | 2 | 2 | – | – | 2 |
| Lymphoma | 1 | – | – | – | – | – | – | – | – | 1 |
For each condition, the tentative radiological diagnosis was retrieved from the patient’s files. Tentative radiological diagnosis differed from definitive histological examination in 38 (41 %) of 92 cases (n = 3 radiological diagnoses were not available). In benign lesions 28 (37 %) of 75 tentative diagnoses differed from the definitive histology. Of 12 intraosseous lipomas, 6 were correctly reported as benign lesions with typical central calcification, whereas, if radiologically missed (n = 6), intraosseous lipomas were suspected to be aneurysmal bone cysts. According to Milgram’s classification [10, 11], intraosseous lipomas were retrospectively classified as two stage I lesions, three stage II lesions and one stage III lesion (n = 6 MRI not available). In three of four cases with metastatic disease plain X-rays were correctly signed out. Imaging showed specific features that were consistent with those of aggressive bone lesion with cloudy, partly osteolytic, partly osteoblastic areas. However, in the case of a 77-year-old male patient with metastatic disease plain X-rays were initially misdiagnosed as stress fracture. In one case of osteosarcoma the time interval between onset of first symptoms and histologically correctly signed out diagnosis was 60 months. This lesion was initially diagnosed as a simple bone cyst and treated with curettage alone in terms of an unplanned excision (whoops procedure [15]) leaving a residual tumour
ND not documented
aMore than one tentative diagnosis was made