Discrete synchronous multifocal osteoid osteoma of the humerus.

A 24-year-old patient is described who had a 4-year history of pain in the right upper arm, with distinct night pain, that responded to salicylates. From the findings on conventional radiography, bone scintigraphy and MRI a multifocal osteoid osteoma was suspected, with one focus in the cancellous region of the greater tuberosity and a second cortical focus at the proximal humeral diaphysis. The resection "en bloc" of both tumors and histological examination confirmed the diagnosis. The patient was painfree after the curative resection of the two osteoid osteomas. Osteoid osteoma is a frequently found benign bone tumor, accounting for approximately 11% of cases. In rare cases a multicentric occurrence has been described. A possible occurrence of more than one osteoid osteoma in a single bone, not verified histologically, has been reported only three times in the literature. In patients with scintigraphic and radiographic findings of two foci, discrete synchronous multifocal osteoid osteomas should be suspected.