The Secondary Oxalosis of Renal Failure

Polarizable crystals in apocrine sweat gland tumors: A series of 3 cases

Polarizable calcium oxalate (CaOx) crystals have been well documented in breast biopsies, generally associated with benign apocrine metaplasia. In contrast, polarizable crystals are only rarely reported in skin adnexal neoplasms. We report 3 different cases of sweat gland tumors with polarizable crystals morphologically suggestive of CaOx: 1 apocrine hidrocystoma and 2 tubular apocrine adenomas. The histologic features were examined in 3 cases. Clinical presentation summary included 2 males and 1 female, ages 53 to 74 years, with lesions located on the left cheek, inferior vertex scalp and the left eyebrow. All 3 cases showed polarizable, geometric, plate-like and fractured, colorless crystals within the lumens of the neoplasm. Of note, these crystals were seen only on the toluidine blue-stained section of Case #1, but were not present on the corresponding permanent section. We hypothesize that polarizable crystals may be present in sweat gland neoplasms more often than previously documented, but that they may often dissolve with routine processing, accounting for their rare visibility. We highlight this rare finding, and suggest that it may be underreported. We only noted this finding in benign apocrine tumors; further investigation would be necessary to determine whether these crystals are also seen in other cutaneous adnexal neoplasms.

Cutaneous oxalate deposition in a hemodialysis patient

We describe calcium oxalate and amyloid arthropathy with cutaneous calcinosis without vitamin C supplement. A 34-year-old woman developed glomerulonephritis requiring chronic hemodialysis. Seven years after beginning hemodialysis, multiple crystal deposits appeared in her skin; she also presented with arthralgia and gait disturbance. A skin biopsy was performed, which disclosed calcium oxalate deposition. In addition, a right femoral neck prosthetic replacement was performed. Pathologic examination of the hip synovia revealed diffuse calcium oxalate, amyloid, and iron deposition. Calcium oxalate and amyloid arthropathy with synovial hemosiderosis was diagnosed, and therapy with desferal and high-flux membrane dialysis was started. Clinical improvement occurred after 6 months.