Clinical Manifestations of Skin Cancer in the Nailbed

Squamous Cell Carcinoma Presentations

• The British Journal of Dermatology reports that skin cancer in the nailbed most commonly presents as squamous cell carcinoma (SCC) with hyperkeratotic, warty proliferations, nail fold erosions, periungual swelling, paronychia, or ulceration of the lateral nail groove 1, 2
• Hyperkeratotic, papillomatous or warty proliferations on any part of the nail unit or periungual tissue are common clinical features of SCC, according to the British Journal of Dermatology 1, 2
• Erosions or scaling of the nail fold with whitish cuticle appearance are also common clinical features of SCC, as reported by the British Journal of Dermatology 1, 2
• Periungual swelling and paronychia with fissure or ulceration of the lateral nail groove are additional clinical features of SCC, according to the British Journal of Dermatology 1, 2
• Granulation-like tissue beneath with scabbing at the lateral nail groove is another clinical feature of SCC, as reported by the British Journal of Dermatology 1, 2
• Subungual involvement is the most common presentation of SCC in the nail unit, according to the British Journal of Dermatology 1, 2
• Onycholysis (nail plate separation from nail bed) with extensive hyperkeratosis of the nail bed is a clinical feature of SCC, as reported by the British Journal of Dermatology 1, 2
• Dystrophic or ingrown nail bed changes are also clinical features of SCC, according to the British Journal of Dermatology 1, 2
• Longitudinal melanonychia has been reported as a presenting feature of SCC in situ, though this is less typical, as reported by the British Journal of Dermatology 1, 2
• The presence of ulceration, bleeding, or a nodule indicates transformation from in situ to invasive carcinoma, with a metastasis rate of approximately 2%, according to the British Journal of Dermatology 1, 2, 3

Critical Diagnostic Pitfalls

• Diagnosis of nail unit malignancies tends to be significantly delayed because of initial misdiagnosis as benign lesions or delay in performing biopsy, as reported by the British Journal of Dermatology 1, 2, 3
• Biopsies can be open to misinterpretation, and distinguishing SCC in situ from invasive SCC may be difficult with periungual lesions due to the three-dimensional nature of the nail bed, according to the British Journal of Dermatology 1, 2
• The nail plate must be sufficiently removed to expose the underlying lesion, and the nail matrix must be sampled by a practitioner skilled in nail apparatus biopsy, as recommended by the British Journal of Dermatology is not available, however Praxis Medical Insights recommends excisional biopsy is preferred when feasible, encompassing the entire lesion, while incisional biopsy is acceptable for larger lesions but must include adequate sampling of the nail matrix 4