Nephrogenic Systemic Fibrosis with Osseous Metaplasia in a Kidney-Pancreas Transplant Patient.

A French (Caucasian) woman with a history of nonobstructive hypertrophic cardiopathy, type 1 diabetes mellitus, cataract, and ante-hypophysary insufficiency had undergone multiple magnetic resonance imaging (MRI) studies. She had developed end-stage renal disease (ESRD) and had undergone hemodialysis for 10 years before receiving a kidney-pancreas allotransplantation at the age of 48 years. She received antithymocyte globulins as induction immunosuppression and steroids (5 mg/d), mycophenolate mofetil (2 g/d), and tacrolimus (5 mg/d) as maintenance immunosuppression. Following transplantation, she underwent a cerebral MRI with injection of a gadolinium-based contrast agent (GBCA) in the work-up for Schwartz-Bartter syndrome. Shortly thereafter, she progressively developed cutaneous infiltration, sclerosis, and hyperpigmentation on her extremities and back (Figure 1), firm nodules on the thighs and the right hand, and confluent papules on the back, all of which were asymptomatic. She had no facial involvement, sclerodactyly, periungual telangiectasias, Raynaud syndrome, or arthralgias. Histologic examination showed mild epidermal hyperplasia and a thickened dermis containing several fibroblasts and some histiocytes (Figure 2a). The alcian blue stain revealed increased dermal mucin deposits (Figure 3b). Remarkably, several round-to-ovoid, well-limited yellowish collagenous structures containing basophilic (elastic) fibers were seen in the dermis (Figures 2b, 2c, 3a, and 4a). These "elasto-collagenous balls" stained blue with Masson's trichrome stain (Figure 4c); the orcein stain confirmed the presence of elastic fibers within them (Figure 4b). Some orange-yellow elasto-collagenous balls contained osteocytes, indicative of osseous metaplasia (Figure 5); these were von Kossa stain-positive, highlighting calcium deposition (Figure 4d). Immunohistochemically, the dermal fibroblasts were variably CD34-positive. Factor XIIIa+ dermal dendrocytes and histiocytic, occasionally multinucleated, CD68+ cells were also seen. (SKINmed. 2022;20:145-148).