Locally Aggressive Primary Intraosseous Paraganglioma of Sacrum.

Primary Intraosseous Paraganglioma (PGL) of sacrum is highly uncommon. Few of the spinal PGL reported were mostly intradural mass. Paraganglionic tissue is usually not present in the bone. So far, only seven cases of primary intraosseous sacral PGL have been reported in the literature. There are no dependable prognostic histological features to differentiate benign from malignant PGL. The only unequivocal criterion for malignancy is metastasis to an organ where paraganglionic tissue is normally not present. However, an aggressive nature can be identified histologically by loss of architecture, decreased or absent sustentacular cells and Ki-67 index of > 3%. We report a case of an elderly male who was admitted with complaints of swelling in the lower back with associated radiating pain and difficulty in sitting of two months duration. A diagnosis of sacral chordoma was made on Magnetic Resonance Imaging (MRI). No other mass was detected elsewhere in his body. The patient underwent surgical excision followed by radiotherapy. On histopathology and immunohistochemistry, a diagnosis of locally aggressive primary intraosseous PGL of sacrum was rendered. Hence, when evaluating a lytic sacral mass, PGL has to be considered as a differential diagnosis.