Acute neck pain caused by pseudogout attack of calcified cervical yellow ligament: a case report.

BACKGROUND Calcification of the yellow ligament sometimes compresses the spinal cord and can induce myelopathy. Usually, the calcification does not induce acute neck pain. We report a case of a patient with acute neck pain caused by calcium pyrophosphate dihydrate in a calcified cervical yellow ligament. CASE PRESENTATION A 70-year-old Japanese woman presented with acute neck pain. She had a moderately high fever (37.5 °C), and her neck pain was so severe that she could not move her neck in any direction. Computed tomography showed a high-density area between the C5 and C6 laminae suspicious for calcification of the yellow ligament. Magnetic resonance imaging showed intermediate-signal intensity on T1-weighted imaging and high-signal intensity on T2-weighted imaging surrounding a low-signal region on both T1- and T2-weighted imaging with cord compression. There was a turbid, yellow fluid collection in the yellow ligament at the time of operation. Histologically, calcium pyrophosphate dihydrate crystals were found in the fluid, and she was diagnosed as having a pseudogout attack of the yellow ligament. CONCLUSIONS Pseudogout attack of the cervical yellow ligament is rare, but this clinical entity should be added to the differential diagnosis of acute neck pain, especially when calcification of the yellow ligament exists.