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Massive calcium pyrophosphate crystal deposition at the craniovertebral junction.

A 76-year-old woman was referred to our hospital for evaluation of neck pain and progressive weakness. Physical examination showed the patient’s head to be thrustforward. Palpation ofthe neck revealed multiple areas of tenderness overlying the occiput and the midline of the neck. Neck motions were markedly restricted. Neurologic examination of the extremities revealed diffuse weakness throughout all muscle groups. Sensory examination was intact. Reflexes were active and symmetric with an occasional beat of clonus in the legs. Perianal sensation was intact to light touch and pinprick, but anal sphincter tone was diminished. Admitting laboratory workup revealed a normal complete blood cell count, urinalysis, electrolytes, and chemical profile. The erythrocyte sedimentation rate was 10 mm in the first hour. Radiographic examination included a cervical spine series, multidirectionaltomography (figs. 1A and 1 B), bone scanning, metrizamide myelography, computed tomography (CT) with metrizamide (fig. iC), bilateral carotid angiography, and magnetic resonance imaging (MAI) (fig. 1D). A joint survey was performed after the histologic diagnosis was made. The extent of the bony destruction was well seen on multidirectional tomography (figs. i A and i B). The CT scan identified a calcified mass and displacement of the cord posteriorly (fig. iC). MRI showed displacement of the spinal cord, which draped over a low-signal-intensity mass (fig. 1D). The character and location of the mass were suggestive of a chordoma or a chondrosarcoma. The patient underwent anterior decompression via a transoral approach. After removal ofthe anterior arch of Cl and the thin eroded odontoid process, a white, globular, soft-tissue mass was encountered. The mass was curetted, and 2 weeks later, an occiput-to-C2 fusion was performed. The patient had a smooth postoperative course after both operations, and strength gradually returned in her extremities. Pathologic specimen was processed and stained with hematoxylin and eosin. Polarized light revealed birefringent crystals, while compensated polarized light with a first-order red plate revealed the characteristic crystals of CPPD (fig. 1 E). Energy-dispersive x-ray microanalysis revealed a calcium-to-phosphorous ratio equivalent to that of CPPD.