Cutaneous spindle cell squamous cell carcinoma successfully managed with nivolumab monotherapy

Programmed death receptor-1 (PD-1) inhibitors, such as cemiplimab, pembrolizumab and nivolumab, are used in the treatment of cutaneous squamous cell carcinoma (SCC) [1–3]. In Japan, nivolumab is approved for the treatment of unresectable advanced or recurrent epithelial skin malignancies [1]. However, clinical data on the use of nivolumab for cutaneous SCC remain limited. We report a case of unresectable, advanced cutaneous spindle cell SCC that was successfully treated with nivolumab monotherapy.
An 84-year-old Japanese man presented with a four-month history of an asymptomatic left preauricular mass that had gradually increased in size. His medical history included hypertension, exertional angina and sarcoidosis for which he was treated with prednisolone. Physical examination revealed a slightly elevated mass measuring 4.5 × 2 cm with crusts and central ulceration in the left preauricular area (figure 1A). A skin biopsy of the mass revealed spindle-shaped cells with hyperchromatic nuclei infiltrating the dermis and subcutis (figure 1B). The dermal infiltrating tumour was partially continuous with the epidermis. Immunohistochemical analysis demonstrated diffuse positivity for CK5/6, CK14, vimentin and p40, whereas α-SMA, S-100, HMB45, CD34 and Ber-EP4 were negative (figure 1C-K). The Ki-67 index was 90%. Computed tomography revealed a well-defined mass in the left preauricular area (figure 1L), without evidence of lymph node involvement or metastasis. Therefore, cutaneous spindle cell SCC was diagnosed…