Primary bone lymphomas thought to be osteomyelitis urgently demand a rapid diagnosis in bone pathology.

We describe in detail three cases of primary bone lymphoma (PBL), initially treated as osteomyelitis of unknown etiology. These cases show which difficulties can occur with diagnosing this entity and highlight the urgent need for rapid diagnostic results in the field of bone pathology. Case 1: A 22-year-old man with the very rare diagnosis of precursor B-lymphoblastic lymphoma in the tibia (previously published). Case 2: A 13-year-old boy with an anaplastic large cell lymphoma of the "os pubis". With initial diagnosis pointing to multifocal osteomyelitis, histology of the left iliac crest revealed a florid/chronic osteomyelitis. During clinical regression with a new osteolytic lesion, he received treatment for chronic recurrent multifocal osteomyelitis. Case 3: A 60-year-old man with an anaplastic large cell lymphoma of the right sacrum, accompanied by a putrid, florid/chronic osteomyelitis. At first, an incisional biopsy revealed a florid/chronic osteomyelitis-only.

Recurrent giant cell reparative granuloma of the skull base and the paranasal sinuses presenting with acute one-sided blindness.

The etiology, pathogenesis, histopathologic diagnosis, prognosis, and treatment of giant cell reparative granulomas of the skull are controversial. We report a 14-year-old girl with an advanced recurrent giant cell reparative granuloma of the skull base and paranasal sinuses whose only clinical manifestation was a loss of vision. After undergoing endovascular catheter embolization, the patient underwent repeated surgical resections of the mass via a combined frontobasal and modified infratemporal approach followed by radiation therapy. Histopathologic examination confirmed the diagnosis of giant cell reparative granuloma. A traumatic event in the patient's history-a fossa canina abscess followed by tooth extraction 14 months before admission-supports the theory of a reactive reparative process as a pathogenetic mechanism for this disease. Histopathologic criteria and clinical aggressiveness must be considered to achieve adequate treatment of giant cell lesions of the skull.