[New knowledge on the calcium pyrophosphate dihydrate (CPPD) crystal deposition disease in the cervical ligamentum...

A case of 64-year-old Japanese woman with cervical radiculomyelopathy caused by the deposition of both calcium pyrophosphate dihydrate (CPPD) and hydroxyapatite crystals in the cervical ligamentum flavum is reported. The patient developed paresthesia in her both hands and gait disturbance in the previous six months. Neurological examination revealed generalized hyperreflexia and hypesthesia in the C7 region. Neuroradiologically, two nodular opacifications were shown in the C3-4 and C5-6 level. CT scan revealed linear and symmetrical calcifications in the C3-4 and nodular calcifications in the C5-6 level. En bloc laminectomy was performed and the patient was discharged from the hospital with improvements of neurological symptoms. Specimens of the spinal laminae and ligamenta flava were studied by light microscopy, scanning electron microscopy (SEM), energy dispersive X-ray microanalysis (X-MA) on SEM, and an X-ray diffraction study was carried out on the crystals. The results showed A. CPPD crystal depositions throughout the ligamenta flava together with a minimal thickening of the ligaments. The deposition was seen in the midzone of the ligaments forming a plate-like distribution and forming lines in the cut surface, the latter coincided well with the CT finding at the C3-4 level. B. The nodule (7 X 6 X 6 mm in size) at the C5-6 level was composed of two crystals, CPPD and hydroxyapatite, the latter being encased by the former. The thickness of the CPPD layer was quite thin varying from 10 to 100 mu. Myelographically, the spinal cord was most severely compressed by the C5-6 nodule. C. Because of the absence of family histories and predisposing factors, the case was considered one of primary or idiopathic CPPD crystal deposition disease. The origin of the deposition of mixed crystals was discussed and it appeared likely that the central part of CPPD crystal deposition had transformed to hydroxyapatite at the C5-6 level. In the literature a considerable number of cases have been reported under the title, "Calcification of the Ligamentum Flavum", and some of them have been shown to have hydroxyapatite deposition. Considering the great similarities in clinical, radiological and histological findings between the so-called "calcification of the lig. fl." and CPPD crystal deposition disease, the present case was the first to clearly indicate that these two conditions belong to a single category, i.e. CPPD crystal deposition disease.(ABSTRACT TRUNCATED AT 400 WORDS)