Eosinophilic granuloma of bone: two case reports.

Eosinophilic granuloma (EG) is a benign, self-limiting disorder that usually involves a single bone. However, there is a growing evidence that the clinical picture of EG is protean. We report two cases with EG that showed rare presentations. Case 1: A 14-year-old girl complained of headache in the left parietal region for several days. The initial examination was normal. During the next three weeks, her headache was progressive and she noticed a tender swelling on her head. Cranial computed tomography (CT) revealed an osteolytic lesion on the left parietal bone. On magnetic resonance imaging (MRI), the lesion corresponded to a tumor that arose from the intradiploic region, and showed both extracranial and epidural extension. She underwent tumor resection and a diagnosis of EG was made on pathological examination. An immunohistochemical study with Ki-67 suggested accelerated growth of the tumor cells. Case 2: A 1.9-year-old boy suddenly complained of a pain in the back and soon had difficulty in walking without help. Several days later, he became unable to sit or walk. On examination, he had spastic paraplegia in addition to painful swelling on the back. A myelogram showed a block just below the T2 vertebra. Chest CT scanning disclosed that a tumor lying posterior to the T2 vertebra was causing marked cord compression and destruction of the posterior elements of the spine. The tumor extended at T1-T3 vertebral levels. He underwent tumor resection and recovered neurological ability. EG should be considered as a differential diagnosis for patients with osteolytic lesions who exhibit aggressive clinical features.