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13, 17). Despite the lack of PD-L1 expression, we initiated systemic treatment with nivolumab at 3 mg/kg body weight biweekly. The tumor was initially stable in size but progressed in the further disease course (Fig. 1b). Thus, nivolumab was discontinued after 11 treatment cycles. As next treatment option, we considered injection of T-VEC. Patients with primary mucosal melanoma were excluded from the pivotal trial and physicians are advised to avoid any contact of T-VEC with mucous membranes during the application procedure. Herpes virus type 1 shows a strong tropism for mucous epithelia of the oral cavity and exposure of T-VEC may result in uncontrolled herpes infection, even though this oncolytic virus cannot replicate in healthy cells due to a lack of the infected cell protein 34.5 (ICP34.5) and was safe in cutaneous melanoma of the head and neck in the OPTiM analysis [2]. We finally refrained from T-VEC and choose interleukin-2 (IL-2) as intralesional application in off-label use. Due to its exophytic growth pattern, a part of the mass was ablated with superficial shave excision prior to IL-2 injection to better reach the base of the tumor. Subsequently, the patient received intratumoral applications of 3–6 million international units IL-2 (Proleukin) per day three times a week for 28 days. The administration dose, frequency, and duration of treatment were determined in relation to the tumor size, specifically following the recommendations of a phase 2 trial in metastasized cutaneous melanoma [3]. The injections were well tolerated. Common adverse events of intralesional IL-2 such as fever, nausea, fatigue, or dizziness were not observed, although the injections were reported painful by the patient. There was a striking response with shrinkage of the tumor to only a small black patch of the hard palate, starting 3 weeks after treatment was initiated. The surrounding area showed discrete hypopigmentation, reminiscent of the typical vitiligo-like areas reported in adjacent Dear Editors,