Statistics from Altmetric.com
A 48 year old woman with end stage renal disease who had been on peritoneal dialysis since 1998 presented with multiple enlarging nodules over both hands (fig 1), especially around the wrists. They were non-tender and clinically resembled gouty tophi. The fasting serum urate concentration was normal, but serum parathyroid hormone and calcium-phosphate product were raised. On examination, two relatively large subcutaneous lesions were also found on her back. They were firm in consistency and slightly lobular in appearance, similar to those found on her hands. Radiography of the lesions revealed heavy calcification (figs 2 and 3). Fine needle aspiration of the hand nodules and her back lumps yielded thick milky white material, which under the microscope demonstrated some granular and crystalloid eosinophilic material with significant calcification and no viable cells. The clinical presentation and histological findings were characteristic of tumoral calcinosis.
This case illustrates a rare differential diagnosis of a subcutaneous nodule or tumour-like lesion in a patient with end stage renal disease. It can mimic a soft tissue tumour, like a leiomyoma or leiomyosarcoma, or it may be confused with a gouty tophus, which is not uncommon in patients with impaired renal function. Vigorous control of the secondary hyperparathyroidism and increasing dialysis remain the mainstay of treatment. A high level of suspicion of this rare entity and a correct diagnosis can avoid unnecessary surgical intervention.