Nitrosamine (and /or Losartan/ Hydrochlorothiazide) Induced Pretibial Located Lentigo Maligna: First Reported Case in the World Literature

Abstract

A 66-year-old Caucasian woman presented to the dermatology department with complaints of a pigmented lesion on the left shin. She first noticed the lesion in March 2020, several months prior to presentation but decided to seek medical advice after observing substantial growth in the size and shape of the lesion. She was diagnosed with type II arterial hypertension 6 years ago and was started losartan/hydrochlorothiazide 50 mg / 12.5mg half a tablet daily. The patient visits her general practitioner regularly and her hypertension is well controlled on these medications, had no other concomitant diseases and was relatively healthy for her age. No family history for dermatologic diseases was available. On dermatologic examination, a single superficially spreading pretibial lesion covering 1.8 cm wide and 1.2cm high was noted(Figure 1a). The light greyish-pink pigmented lesion was oval in shape with sharply demarcated borders and no elevation above the surrounding skin. Further laboratory work-up showed no signs of deviations. Based on the clinical and dermatoscopic evidence, the diagnosis of melanoma in situ, lentigo maligna type was made. She was sent for treatment at a specialised hospital for oncological diseases in June 2020 where a surgical excision was performed under local anaesthesia with 0.5cm clear/ negative margins in all directions. The defect was thereafter closed using a full-thickness mesh graft taken from the abdominal region(Figure 1b). The excised tumour was subsequently sent for histological evaluation and was keeping with the clinicopathological diagnosis of lentigo maligna. Immunohistochemical analysis also identified S100 positive nests of cells within the basal lamina, confirming the diagnosis.Postsurgical wound healing with the skin graft was poor due to inadequate graft transplantation whereby necrotic as well as macerated areas were observed leadingto bad cosmetic results (Figure 1c-h).After a multidisciplinary review and follow up, a second operation was performed a month later to remove the necrotic, together with the hypertrophic tissue and a new split skin mesh graft was utilised. Stringent post-operative care, including prophylactic antibiotic therapy was also provided to promote good wound healing which was achieved several months later (Figure 1i).