Brown tumor an uncommon and late manifestation of hyperparathyroidism: a case series done at Tikur Anbessa Specialized Hospital, Addis Ababa.

Brown tumor of hyperparathyroidism is a non-neoplastic osteoclastic process which results in cystic lesions that are often expansile. It occurs rarely and is often a late manifestation of primary hyperparathyroidism (PHPT). Multiple bone involvement is extremely rare. Because of its resemblance with benign tumors if it occurs as a solitary bone lesion and of metastatic bone lesion when it is multiple, differentiation is often difficult without biochemical analysis. Here we presented eight patients who visited Tikur Anbessa Specialized Hospital for the last 15 years with primary skeletal complaints. Out of these six were females and except one patient all had multiple brown tumors. Based on radiographic features only it is often difficult to diagnose the condition and biochemical tests and anterior neck sonography is usually crucial to reach at a definitive diagnosis. Although the occurrence of more than one separate bone lesion in the skeleton usually suggests metastasis, our cases shows that brown tumors should also be included in the differential diagnosis of such lesions, particularly in patients with hyperparathyroidism.