BI29 Two cases of periungual squamous cell carcinoma in situ in immunosuppressed renal transplant recipients

Abstract

Periungual squamous cell carcinoma in situ (SCCis) is uncommon and frequently misdiagnosed, resulting in treatment delays. Management is challenging due to the functional and cosmetic sensitivity of the nail unit. Immunosuppressed patients are at increased risk of nonmelanoma skin cancers. We present two cases of periungual SCCis in immunosuppressed renal transplant recipients, highlighting the need for prompt diagnosis and tailored, multimodal management. A 63-year-old man with skin phototype VI presented with a 6-week history of a tender, pigmented hyperkeratotic periungual lesion on the right third finger with associated nail dystrophy. He was taking prednisolone, tacrolimus and mycophenolate and had coexisting epidermodysplasia verruciformis. Incisional biopsy demonstrated SCCis, positive for high-risk human papillomavirus (HPV). Due to clinical suspicion of invasive disease, he underwent nail ablation and full-­thickness skin grafting, with no local recurrence. Over subsequent months, multifocal periungual verrucous and hyperkeratotic lesions developed on the left third and fourth toes, and subsequently across multiple fingers on both hands. Some nails became dystrophic. Mycology was negative. Further biopsies confirmed widespread periungual HPV-related SCCis. A pragmatic, multipronged approach was employed with renal team support: cycles of curettage and cautery followed by imiquimod under occlusion, reduction of immunosuppression, prophylactic acitretin initiation and HPV vaccination. Complete disease clearance was achieved over an 18-month period and maintained at the 8-year follow-up. Mohs micrographic surgery (MMS) was considered but not required. A 58-year-old man with phototype II skin, taking prednisolone, tacrolimus and mycophenolate, presented with a 5-year history of left-thumbnail dystrophy, periungual hyperkeratosis, chronic paronychia and intermittent bleeding following trauma. Incisional biopsy confirmed SCCis with p16 positivity. He was treated with imiquimod under occlusion and referred for MMS. Periungual SCCis should be suspected in persistent and progressive periungual hyperkeratosis in immunosuppressed patients. A low threshold for early biopsy is essential. Effective management may necessitate a combination of topical, surgical and systemic strategies to achieve disease control while preserving function.