A 67-year-old man presented with asymptomatic small nodules on his right lower leg since one month earlier. Attending doctors in the Department of Hematology and Oncology at our hospital suspected an infectious skin disease of unknown etiology and referred him to our department. At the initial examination, his right foot was broadly swollen with dark-reddish discoloration and scattered ulcerated nodules that discharged spontaneously. The rashes were painful, but there was no systemic fever. The patient was considered immunocompromised due to long-term administration of cyclosporin (75 mg/day) and prednisolone (3 mg/day) for nephrotic syndrome. Hematoxylin and eosin-stained histopathological examinations revealed mild inammatory inltrates with neutrophils and histiocytes in the supercial dermis, and granuloma with abscess formation,consisting of dense inltration of neutrophils, histiocytes, and multinucleated Langhans-type giant cells, in the deep dermis. Swab culture grew slow-growing bacteria four weeks after inoculation,which were identied as Mycobacterium haemophilum through nucleotide sequencing analysis. Consequently, the patient was diagnosed with cutaneous non-tuberculous mycobacteriosis. The patient was treated with systemic antibacterial agents (clarithromycin 800 mg daily, ciprooxacin 400 mg daily, and rifampicin 450 mg daily), resulting in the disappearance of the ulcers on the right leg except for the dorsum of the foot at three months and complete resolution of all ulcers at 17 months. This case highlights the importance for dermatologists to consider cutaneous non-tuberculous mycobacteriosis, particularly with the increased use of immunosuppressive drugs in recent decades. Skin Research, 23 : 87-92, 2024

A 54-year-old woman was diagnosed with right breast cancer ten months prior to her rst visit to our department. Letrozole was administered orally for about nine months as preoperative therapy,followed by a right mastectomy. After resuming oral administration of letrozole as postoperative therapy, she developed edematous erythema and blisters primarily on her extremities 10 days later,prompting a referral to our department. Upon examination, the palpebral conjunctiva was congested, there was no pseudomembrane formation or corneal epithelial defect, and a slight fever of 37.3°C was observed. Histopathological examination of her skin indicated epidermal necrosis with subepidermal blisters. She was diagnosed with erythema multiforme major. Considering the possibility of a drug eruption caused by letrozole, we discontinued letrozole and started her on 55 mg of oral prednisolone daily (1mg/kg/day). The skin lesions resolved within three weeks. A druginduced lymphocyte stimulation test for letrozole, performed ve days after the initiation of oral prednisolone, was positive. Aromatase inhibitors, used as adjuvant therapy for breast cancer, block estrogen synthesis by inhibiting the nal step of the estrogen biosynthetic pathway. These inhibitors are classied into nonsteroidal and steroidal types, with letrozole being a nonsteroidal type. Letrozole was approved in Japan in 2006 as an aromatase inhibitor for the treatment of postmenopausal hormone receptor-positive breast cancer. Although a few cases of generalized eruptions that were treated with aromatase inhibitors have been reported, we herein report the present case with additional considerations, including the selection of alternative drugs. Skin Research, 23 : 93-96, 2024

Case 1 was a 30-year-old woman. She had worked as a hairdresser for 10 years and was referred to our department due to suspected anaphylaxis caused by hair-bleaching products. During the bleaching of her own hair, she developed facial swelling, urticaria, dyspnea, vomiting, and lower abdominal pain. Skin-prick tests werepositivefor thehair-bleaching products (as is, 10% aqua, and 1% aqua) as well as sodium persulfate (1% aqua, and 0.1% aqua), potassium persulfate (1% aqua and 0.1% aqua), and ammonium persulfate (1% aqua, and 0.1% aqua). The symptoms were diagnosed as anaphylaxis due to exposure to sodium persulfate, potassium persulfate, and ammonium persulfate in the hair-bleaching products. Case 2 was a 40-year-old woman who developed an itchy rash on her limbs, forehead, ears, and neck, and dyspnea while bleaching her hair. Skin-prick tests were positivefor thehair-bleaching products (as is, and 10% aqua). Shewas diagnosed with anaphylaxis dueto thehair-bleaching products. Case1 has been ableto continueworking as a hairdresser by avoiding contact with hair bleach and carrying an adrenaline injection. Contact urticaria and anaphylaxis due to hair-bleaching agents have been reported in a small number of cases in Japan, with three published papers and ve conference proceedings. Given the increased use of bleaching agents in recent years, we expect the number of cases to rise. It is necessary to raise awareness among thepublic and themedical community about contact urticaria and anaphylaxis caused by hairbleaching agents. Skin Research, 23: 97-102, 2024

A 55-year-old male presented with a black macule on his back, accompanied by a 6-month history of itching. Malignant melanoma was suspected by his previous doctor, prompting a referral to our department. At the initial visit, a 10×8 mm variegated black macule was observed on the middle back. Biopsy specimens were inconclusive for differentiating between dysplastic nevus and melanoma. Total resection was performed with a 5 mm margin. Imaging studies, including CT and PET-CT, did not detect any distant metastases. A completely excised specimen revealed atypical,spindle-shaped, or pagetoid melanocytes scattered in a pagetoid pattern in the basal and spinous layers. There was a band-like inammatory inltrate and concentric brosis in the supercial dermis below the irregularly elongated and effaced rete ridges. Immunohistochemically, tumor cells were positive for S100-protein, HMB45, MelanA, and PRAME. p16 was partially deleted, and the Ki-67 proliferation index was about 30％. A BRAF V600E mutation was detected. Based on these ndings, a diagnosis of supercial spreading melanoma was established. There was no recurrence or metastasis observed during an 11-month follow-up period. Skin Research, 23 :103-109, 2024

A 50-year-old woman developed erythema on her extremities ve days after she received her fourth dose of the Pzer/BioNTech COVID-19 vaccine (COMIRNATY^○R ). Nine days postvaccination, she was referred to our department with widespread erythema and a fever of 38°C. The patient exhibited edematous erythema, which tended to coalesce on the extremities and trunk,accompanied by small nonporous pustules on the lower abdomen and axilla. Blood tests revealed leukocytosis with a predominance of neutrophils and elevated CRP. No bacteria were detected in cultures from the pustules or blood. Histopathology of the pustules from the lower abdominal area showed inammatory cell inltration, predominantly neutrophils, from within to below the stratum corneum, along with eosinophilic inltration around blood vessels in the supercial dermis. Given the absence of new medications, the patient was diagnosed with acute generalized exanthematous pustulosis (AGEP) induced by the COVID-19 vaccine. After admission, she was administered intravenous methylprednisolone pulse therapy and oral prednisolone. The rash resolved rapidly,with membranous desquamation. She was discharged on the 14th day after admission, and no recurrence was observed after completing oral prednisolone therapy. Several cases of AGEP following COVID-19 vaccination have been reported in Japan and internationally, supporting our ndings that the present case was vaccine-related. Skin Research, 23 : 110-114, 2024

A 62-year-oldwoman presentedto our hospital with a nodule on the proximal nail foldof her left index nger, which hadbeen present for one year. The nodule measured6mm×2 mm, hada blackish-brown color, andexhibitedheterogeneous tones. Dermoscopy revealedan irregular pigment network, a linear arrangement of brown dots, and homogeneous pigmentation. Skin biopsy conrmedthe diagnosis of pigmentedBowen’s disease. The patient underwent surgical excision of the lesion, followedby articial dermis grafting. The initial surgical specimen showed tumor cells at the ventral proximal nail fold margin, necessitating an additional excision. The patient has remained free of recurrence for four years post-treatment. Bowen’s disease is a tumor that predominantly occurs in the extremities andtrunk of the elderly. PigmentedBowen’s disease is a rare subtype,accounting for about 2％ of all cases. The most common sites of onset are the ngers andpubic region, andit is thought to be associatedwith human papillomavirus infection. Diagnosing pigmentedBowen’s disease can be challenging due to its similarity to other pigmented lesions such as malignant melanoma. However, dermoscopy is a useful tool in the diagnostic process. Blackish lesionsonthengers shouldbe examinedwith dermoscopy to differentiate pigmentedBowen’s disease from other pigmented lesions. Skin Research, 23 : 115-119, 2024

A 72-year-old female was referred to our hospital with asymptomatic redness and swelling of the right upper eyelid that she noticed a month earlier. Physical examination revealed edematous erythema with mild inltration localized to the right upper eyelid. Blood testing showed weakly positive antinuclear antibodies. The patient had been taking rosuvastatin for several years, which was positive in a drug-induced lymphocyte stimulation test (DLST). Histopathological examination revealed lymphocytic inltration around the blood vessels and appendages in the dermis, along with mucin deposition throughout the dermis. No decrease in MED and MRD was observed in an ultraviolet irradiation test. Based on these ndings, the patient was diagnosed with lupus erythematosus tumidus (LET). Topical steroids had no effect on her condition. After instructions to avoid light exposure and switching her medication from rosuvastatin to another drug, her skin symptoms spontaneously disappeared in about six months. LET is one of the rarer forms of cutaneous lupus erythematosus. Drug-induced LET is considered extremely rare, and we suspected that rosuvastatin was involved in the present case. We report this case with a review of the literature. Skin Research, 23 : 120-124, 2024

A 28-year-old woman presented with rashes on her ngers, face, anterior chest, and lumbar skin,along with painful mucosal erosions of the lips and hard palate. Laboratory tests revealed leukopenia, lymphopenia, decreased complement levels, high levels of anti-nuclear antibodies, and positive anti-Smith antibodies. Skin biopsy showed vacuolar changes at the dermoepidermal junction, leading to a diagnosis of systemic lupus erythematosus (SLE) based on the 2019 ACR/EULAR classication criteria. Oral prednisolone was administered, but improvement of cutaneous symptoms was insufcient. Following 14 days of anifrolumab administration, the mucocutaneous symptoms almost disappeared. However, the patient developed severe insomnia,suicidal ideation, and acute psychomotor agitation. Subsequently, she was transferred to a specialized facility and diagnosed with neuropsychiatric SLE. This case underscores the importance of considering neuropsychiatric SLE in patients presenting with psychiatric symptoms. Skin Research, 23 : 125-133, 2024