Case
One year after kidney transplantation, a 70-year-old man returned to haemodialysis. Induction had consisted in basiliximab, mycophenolate, prednisone and cyclosporine, the latter was switched to tacrolimus after 9 months. Because of rejection under reduced immunosuppression, the graft was removed 6 months after returning to haemodialysis and immunosuppression was completely stopped.
Twelve months later, a large skin tumour grew close to the arteriovenous fistula within 4 weeks (Figure 1). A surgical excision was undertaken. Macroscopy showed a spindled skin specimen with a centrally located dome-shaped nodule. On histological examination, the tumour presented with crateriform architecture and centrally located papillary proliferation within a keratin plug consistent with the diagnosis of a keratoacanthoma (Figures 2 and 3). Keratoacanthomas are benign skin tumors developing from epidermal and hair follicle keratinocytes. Even after histological examination, keratoacanthomas are hard to distinguish from squamous cell carcinoma [1], the most frequent skin cancer after transplantation [2]. Additionally, both tumours have similar risk factors such as ultraviolet light and human papillomavirus infection [3].
Fig. 1.
1.6 × 1.5 × 0.5 cm measuring keratoacanthoma close to the arteriovenous fistula used for dialysis access.
Fig. 2.
Margin of a keratin-filled crater with papillary proliferation of the squamous epithelium.
Fig. 3.
Mild cellular atypia, on the right side an intraepithelial micro-abscess.
Hence, after returning to chronic haemodialysis, a regular dermatological examination is mandatory for previously transplanted patients.
Acknowledgments
Conflict of interest statement. None declared.
References
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