Acta Dermato-Venereologica 99-13CompleteContent | Page 29

1301 SHORT COMMUNICATION Multiple Keratoacanthoma-like Lesions in a Patient Treated with Pembrolizumab Marion FRADET 1 , Vincent SIBAUD 2 , Emilie TOURNIER 3 , Laurence LAMANT 3 , Serge BOULINGUEZ 1,2 , Aurore BRUN 1 , Cecile PAGES 2 and Nicolas MEYER 1,2 1 Department of Dermatology and 3 Department of Pathology, Paul-Sabatier Toulouse III University; IUCT-oncopole and CHU de Toulouse, 24 chemin de Pouvourville TSA 30030, FR-31059 Toulouse, 2 Department of Dermatology, IUCT-oncopole, and 4 Inserm UMR 1037-CRCT, Toulouse, France. E-mail: [email protected] Accepted Aug 22, 2019; E-published Aug 22, 2019 The anti-tumour efficacy of anti-programmed cell death (anti-PD1) therapy has been demonstrated in a large range of malignant neoplasms, including metastatic me- lanoma, advanced cutaneous squamous cell carcinoma and lung carcinoma (1). Despite presenting a favour­able safety profile, monoclonal antibodies targeting PD-1 are associated with dermatological toxicities, which af- fect approximately > 30% of treated patients (2). These predominantly manifest as eczema-like maculopapular rashes, lichenoid reactions, vitiligo-like lesions, or flares of psoriasis. These cutaneous adverse events generally have an immune aetiology and can, in most cases, be managed and reversed (3, 4). We report here a case of a patient developing eruptive keratoacanthoma (K-A)-like lesions induced by treatment with pembrolizumab, an anti-PD1 monoclonal antibody. Such eruptions represent an unusual cutaneous toxicity, which has, until now, been very rarely reported. CASE REPORT An 85-year-old man was treated with pembrolizumab for metastatic bronchial squamous cell carcinoma (SCC). After the second treatment cycle he developed hyper- keratotic nodular lesions (more than 30 lesions in total) on the dorsal region of his hands, knees and legs (Fig. Fig. 1. Keratosis eruption after 2 cycles of immunotherapy with pembrolizumab. 1). The mucous membranes and scalp were not affected. The patient had no prior history of skin disease. However, he had experienced chronic exposure to ultraviolet (UV) light during outdoor leisure activities. Histopathological analysis of 3 eruptive lesions showed a similar pattern of infiltrative well-differentiated SCCs. Immunostaining identified a predominantly CD3 + /CD4 + associated T- lymphocyte infiltrate of the basement membrane, with no lichenoid involvement. Anti-PD1 staining was weakly positive. After clinical-pathological concertation, the lesions were diagnosed as keratoacanthoma-like lesions. Since an objective regression of the lung cancer was ob- served, treatment with pembrolizumab was maintained. Clobetasol cream (once per day) was prescribed for to- pical application to the dorsal region of the hands, knees and legs, and the lesions gradually regressed over a few weeks. Complete regression, without scarring, was noted after 3 months (Fig. 2). At the 6-month follow-up, no recurrence or progression of skin lesions was observed. DISCUSSION We report here an additional case of eruptive kerato­ acanthoma-like eruption induced by pembrolizumab. Anti-PD1 antibodies play a major role in the manage- ment of melanoma and locally-advanced or metastatic cutaneous SCCs. The paradoxical development of Fig. 2. Clearance of lesion with propionate clobetasol. This is an open access article under the CC BY-NC license. www.medicaljournals.se/acta Journal Compilation © 2019 Acta Dermato-Venereologica. doi: 10.2340/00015555-3301 Acta Derm Venereol 2019; 99: 1301–1302