Calcinose pseudo-tumorale chez un hémodialysé chronique

Pseudotumoral calcinosis (PTC) is characterized by calcium phosphate crystal deposition in periarticular soft tissues leading to the development of large calcified masses. Although PTC physiopathogeny is not completely clear, the increase in calcium-phosphorus product beyond the threshold value for precipitation as well as severe hyperparathyroidism seem to play a determining role. PTC may even cause recurrent minor joint traumas. In patients on hemodialysis, the frequency of PTC is estimated between 0.5 and 7%, according to case series. Its treatment is controversial. Surgical resection is often recommended. We here report a case of PTC in a patient on haemodialysis. The study involved a 56-year old patient on chronic haemodialysis for 9 years due to indeterminate nephropathy. The patient had suffered from gradual worsening of pain at the level of the right hip associated with difficulties in joint mobilization over the last 6 months. CT scan showed multiple lobed calcified mass, measuring 8.6 x 7.6 x 5.9cm, located very closely to the sciatic nerve, which probably explained the very painful physical symptoms. Laboratory tests showed high phosphocalcic product and hyperparathyroidism. Surgical resection was difficult due to the closeness of the tumor to vasculo-nervous elements. Our study highlights the diagnostic and therapeutic difficulties of PTC. This uncommon disease should be suspected in patients on chronic hemodialysis with periarticular calcified mass suggesting tumor.