The patient was a 56-year-old man who had been diagnosed with pulmonary sarcoidosis 5 years earlier by lung biopsy at another hospital. He was referred to our nephrology department a year earlier due to findings suggestive of renal disfunction on physical examination. At the time of the visit, he had nodular lesions on the head, forehead, and elbow with many keratotic plugs, and was referred to our department. Skin biopsies were taken from the head and elbow. Histopathology revealed hyperkeratosis and marked acanthosis with pseudocarcinomatous hyperplasia, keratin plugs in the follicular openings, keratin pseudocysts, and mononuclear cell inflammatory infiltration of the upper dermis. Within the dermis, a granuloma composed of epithelioid cells mixed with multinucleated giant cells was observed. Histopathological findings suggested a foreign body granuloma secondary to a ruptured epidermal cyst or folliculitis ; however, previous case reports of sarcoidosis with similar histopathological features have been described as verrucous sarcoidosis. These case reports reported skin lesions with multiple verrucous nodules, characterized histologically by marked keratinization, epidermal thickening, and numerous non-desmoplastic sarcoid granulomas in the dermis. Although the present case had fewer skin lesions than previously reported cases of verrucous sarcoidosis, our findings were consistent with previous case reports, as the patient had a history of pulmonary sarcoidosis and the skin nodules exhibited sarcoidal granulomas with hyperkeratosis and pseudocarcinomatous hyperplasia. Herein, we report a case of verrucous sarcoidosis and review the literature. Skin Research, 24 : 245-250, 2025

Delayed-type hypersensitivity reactions to heparin are uncommon but pose significant clinical challenges. Here, we report a 32-year-old pregnant woman who showed a delayed-type hypersensitivity reaction to a heparin calcium preparation. The patient experienced cerebral infarction with reversible cerebral vasoconstriction syndrome and was treated with subcutaneous heparin calcium injections. Approximately 3 weeks after the start of treatment, blood tests showed an increase in eosinophil counts, and multiple erythema appeared at the abdominal subcutaneous injection site, leading to referral to our department. Both the 48-hour intradermal test and the drug-induced lymphocyte stimulation/lymphocyte transformation test for heparin calcium (derived from porcine intestinal mucosa) were positive. Therefore, we diagnosed delayed-type hypersensitivity reaction due to heparin calcium. After discontinuing subcutaneous heparin calcium injections, the erythematous lesions resolved. Delayed-type hypersensitivity reactions to subcutaneous calcium heparin injections have been frequently reported, most commonly in pregnant women. Clinicians should be aware of this potential adverse event and its management and diagnostic methods. Skin Research, 24 : 251-255, 2025

We report three cases of neuronal intranuclear inclusion disease (NIID). Case 1 involved a 61-year-old female patient with transient visual field impairment, headaches, and sudden forgetfulness. Case 2 involved a 77-year-old male patient with impaired consciousness and visual hallucinations. Case 3 involved a 73-year-old male patient with repeated transient impairment of consciousness. Diffusion-weighted magnetic resonance imaging of the head revealed hyperintense regions, and fluid-attenuated inversion recovery imaging showed diffuse hyperintensity in the bilateral cerebral white matter, raising suspicion of NIID in all cases. Skin biopsies of the abdomen or thigh were performed, and ubiquitin-positive nuclear inclusions were found in sweat gland epithelial cells, fibroblasts, and adipocytes, leading to the diagnosis of NIID. The clinical diagnosis of NIID was challenging because of the wide range in the age of onset and clinical symptoms in these cases. Previously, NIID was mainly diagnosed by autopsy, and there are few reports. Recently, the detection of nuclear inclusions using skin samples has enabled the premortem diagnosis of NIID by skin biopsy, leading to an increase in the number of reported cases. With the aging population, dermatologists are likely to become increasingly involved in diagnosing NIID ; thus, there is a need for them to increase their awareness of this disease. Skin Research, 24 :256-263, 2025

We present two cases of multibacillary leprosy in international visitors to Japan. Case 1 : A 30-year-old male from Indonesia arrived in Japan one year and two months prior to the first visit to our department. One year prior, the patient had skin rashes, which resolved spontaneously. One month prior, the skin rash reoccurred and covered the entire body, prompting him to visit a nearby clinic. Skin biopsy raised suspicion of leprosy, leading to his referral to our hospital. On examination, annular erythematous lesions with hypoesthesia were observed across the body. Skin smears with fite stain from the lesions were positive, and PCR testing identified leprosy-specific DNA, confirming a diagnosis of mid-borderline leprosy. He subsequently returned to Indonesia after the diagnosis. Case 2 : A 26-year-old male from Nepal arrived in Japan seven months prior to the first visit to our department. Three months prior, he noticed pruritus and diminished sensation in his hands, and skin rash appeared over the entire body. He consulted a nearby clinic, and a skin biopsy raised suspicion of leprosy, prompting his referral to our department. At presentation, slightly elevated erythema was distributed diffusely on the entire body. Although sensory loss was not observed in the erythematous lesions, a“glove-and-stocking”pattern of sensory loss was observed, and thickening of median nerves was noted. Both skin smears with fite stain and PCR testing were positive, leading to a diagnosis of borderline lepromatous leprosy. Multidrug therapy (MDT) was subsequently initiated. Systemic steroids for peripheral neuropathy were not administered due to the absence of leprosy reactions. After 8 months, the skin lesions and peripheral neuropathy gradually improved without leprosy reactions. In Japan, a few new cases of leprosy are reported each year, predominantly among international visitors. In order to avoid complications, such as sensory loss and joint deformity, early initiation of MDT is critical, with close monitoring for leprosy reactions. Skin Research, 24 : 264-271, 2025

A 74-year-old woman with rheumatoid arthritis who had been treated with tocilizumab for 10 years. She was admitted to our hospital with the chief complaint of pain and swelling on her left lower leg that was accompanied by low blood pressure, swelling of the entire left lower leg, and purpura. On examination, the laboratory risk indicator for necrotizing fasciitis (LRINEC) score was low (2 points). Four hours after admission, the area of purpura had expanded, and blisters appeared on the left lower leg. Superficial ultrasonography revealed a hypoechoic area along the fascia, suggestive of fluid accumulation. We performed an emergency surgical debridement. Intraoperative findings confirmed necrosis of the left lower leg fatty tissue, and a rapid antigen test for group A streptococcus was positive, leading to a diagnosis of necrotizing fasciitis. The patient survived following two surgical debridement procedures and antibiotic therapy. Tocilizumab is an anti-IL-6 receptor antibody that suppresses fever and the production of acute-phase proteins such as CRP, thereby masking IL-6-dependent symptoms and infection-related laboratory findings. In patients receiving this therapy, necrotizing fasciitis requires careful consideration, as the LRINEC score may be low. Skin Research, 24 : 272-278, 2025

A 56-year-old woman presented with a tumor on the left chest wall that had been progressively growing over the past year. The tumor was large and pedunculated, measuring approximately 52×35 mm. Histopathological examination revealed that the lesion was covered by epidermis and composed of adipose tissue, with no skin appendages observed. The differential diagnosis included solitary nevus lipomatosus superficialis, soft fibroma, and dermal lipoma. Based on the histopathological features and the pedunculated morphology, the lesion was diagnosed as a dermal lipoma arising within a soft fibroma. Skin Research, 24 : 279-283, 2025

Keratoacanthoma is a common, rapidly growing cutaneous epithelial tumor that typically arises in sun-exposed areas and often resolves spontaneously or with minimal treatment. Only a few cases of keratoacanthoma of the nasal vestibule have been reported in the literature, all of which were managed with local excision. Herein, we report a case of a 46-year-old female long-term smoker who presented with a keratoacanthoma of the left nasal vestibule. The patient declined treatment after the skin biopsy and was managed through observation alone. Subsequently, the tumor gradually decreased in size over the next several months and ultimately regressed completely without intervention. This case highlights the potential for spontaneous regression of keratoacanthoma, particularly in rare and anatomically challenging locations such as the nasal vestibule. Further case studies are needed to elucidate the natural course and optimal management of keratoacanthoma in this rare location. Skin Research, 24 : 284-287, 2025

A 38-year-oldwoman presentedwith malignant melanoma of the right nasal cavity and right temporal lobe metastasis. She was administered nivolumab-ipilimumab combination therapy. Five weeks after starting treatment, she developedimmune-relatedcolitis. Nivolumab was stopped and 1 mg/kg/day of systemic prednisolone was introduced. The following week, the patient developed immune-relatedhepatitis. After steroidpulse therapy, the dose of prednisolone was increased to 2 mg/kg/day, but there was no improvement. Mycophenolate mofetil (MMF) and tacrolimus were started; however, there was no improvement in hepatitis. Plasma exchange was performed twice ; however, there was only short-term benefit. Oral azathioprine was then initiated, after which steroids and MMF were gradually tapered without subsequent hepatitis are-ups. The Third Edition JSMO Cancer Immunotherapy Guidelines do not include the use of immunosuppressive drugs other than MMF as a treatment for Grade 3 or higher irAE hepatitis. In the present case, the administration of three immunosuppressive agents in addition to steroids was effective. Skin Research, 24 : 288-291, 2025

A 12-year-old boy presented with swelling and pustules on the right side of his scalp that had developed over the past three weeks while undergoing treatment for atopic dermatitis and asthma. He had been administered antibacterial agents, but his condition had worsened. Direct microscopic examination of plucked hairs was negative ; however, fungal culture of affected hairs and scales identified Trichophyton tonsurans. Histopathological examination of a skin biopsy revealed fungal hyphae within the hair shafts. Based on these findings, we diagnosed kerion celsi. The patient was treated with terbinafine at a dose of 125 mg/day for six weeks, resulting in complete resolution without scarring alopecia. Follow-up hairbrush test was negative. Direct microscopy is the most commonly used diagnostic method for dermatophytosis. However, direct microscopic examination often yields negative results in cases of kerion celsi. In the present case, direct microscopy was negative, and trichoscopy showed no characteristic findings. Nevertheless, fungal culture successfully identified Trichophyton tonsurans. In cases where kerion celsi is clinically suspected, fungal culture should be actively performed to ensure accurate diagnosis. Skin Research, 24 : 292-296, 2025

A 53-year-old man with a history of childhood-onset atopic dermatitis and no prior use of immunosuppressive drugs presented with worsening skin lesions that had progressed over the year preceding his first visit to our outpatient clinic. He was previously diagnosed with chronic eczema by his primary care physician ; however, his condition gradually worsened and became resistant to topical steroids. A skin biopsy at that time revealed no sign of malignancy, and he was referred to ourhospital forfur therevaluation. At the initial examination, he had a large ulcerwith swelling on the right forearm, as well as diffuse erythema on the face and infiltrated brown maculopapular lesions on the trunk and extremities. A repeated skin biopsy and imaging analysis confirmed a diagnosis of stage IVA2 mycosis fungoides (MF). Large-cell transformation was observed in the deep dermis. He underwent radiation therapy, chemotherapy, and molecular-targeted therapy ; however, these treatments were discontinued due to an infection originating from the ulcer. The patient was transferred to another hospital, where he died 3 months after his initial diagnosis due to massive bleeding from an ulcerative lesion on his arm, a rare cause of death in MF. Histopathological analysis revealed marked heterogeneity in Ki-67 expression within the tumor lesion of the forearm, with highly proliferative lymphoma cells showing deep infiltration and vascular invasion at the arteriovenous level. This case highlights the critical role of Ki-67 evaluation in aggressive MF and the importance of repeated biopsies for early diagnosis. Skin Research, 24 : 297-304, 2025

We report a 33-year-old male presenting with a schwannoma on the left upper eyelid. The patient noticed a nodule on his left upper eyelid about 1 year earlier, which gradually increased in size. At the initial visit, he presented with a subcutaneous tumor. The lesion was a dome-shaped, raised subcutaneous mass measuring 2 cm in diameter. It was smooth and elastic-hard. On T2-weighted MRI, the tumor exhibited areas of high and relatively low signal intensity. Histological examination revealed a well-circumscribed tumor with a capsule predominantly composed of acidophilic spindle cells forming a palisading pattern. Acidophilic acellular areas outlined by opposing rows of parallel nuclei (Verocay bodies) were also observed. We diagnosed schwannoma arising from the supraorbital nerve. Schwannoma in the eyelid are rare. Skin Research, 24 : 305-308, 2025

An 86-year-old woman experienced oral discomfort upon waking and was admitted to the emergency care with tongue swelling and respiratory distress. At the initial visit, laryngeal edema and tongue and neck swelling were observed. Mast cell-mediated angioedema was suspected, and the patient was treated with antihistamines and methylprednisolone. One month later, the patient experienced recurrent tongue swelling, which improved following the administration of medications including adrenaline and antihistamine. Hereditary and acquired angioedema were excluded based on the absence of a family history and normal complement levels, including C1 inhibitor. As her symptoms were controlled with continuous antihistamine therapy, a diagnosis of idiopathic angioedema was made. Positive results for the autologous serum skin test and anti-thyroid peroxidase antibodies suggested an autoimmune component in the pathogenesis. Anti-IgE and anti-Fc ε RI antibodies are recognized as autoantibodies involved in the pathogenesis of chronic spontaneous urticaria. Patients with chronic spontaneous urticaria who are positive for autoantibodies have been reported to exhibit higher clinical urticaria scores and longer disease duration compared with those without autoantibodies. Autoimmune-related angioedema may be more severe and harder to treat than non-autoimmune forms, necessitating careful follow-up. Skin Research, 24 : 309-314, 2025

A 60-year-old female was referred to our hospital because of a 3-year history of pruritic sclerotic plaques and a 2-year history of multiple ulcerations on her trunk and extremities. Immunoserological examination was positive for anti-ss-DNA antibody, and negative for anti-Scl-70, anti-centromere, anti-RNA polymerase III, and anti-U1-RNP antibodies. Histopathological examination of a sclerotic lesion revealed thickened collagen bundles in the lower dermis and subcutaneous adipose tissue, accompanied by atrophy of the eccrine sweat glands. Histopathological examination of an ulcer demonstrated dermal inflammation without evidence of vasculitis. Based on the clinical and pathological findings, the patient was diagnosed with generalized morphea. The multiple ulcers on the trunk and extremities improved with systemic prednisolone, oral mycophenolate mofetil (MMF), and debridement of necrotic tissues. Although rare, generalized morphea can manifest with multiple ulcers, which may respond to systemic corticosteroids and MMF. Further studies are needed to elucidate the mechanisms underlying ulcer formation in generalized morphea. Skin Research, 24 : 315-320, 2025

A 77-year-old man had experienced joint pain for approximately one year and was simultaneously diagnosed with myelodysplastic syndrome. He subsequently developed a generalized erythema nodosum-like rash with skin ulceration. Pyoderma gangrenosum was initially suspected, and oral steroid therapy was initiated ; however, the rash persisted and the clinical presentation gradually resembled Sweet’s syndrome. Because the symptoms were refractory to oral steroids and the patient also had myelodysplastic syndrome and arthritis, VEXAS (Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic) syndrome was suspected, prompting genetic testing. A mutation in the UBA1 gene confirmed the diagnosis of VEXAS syndrome. Azacitidine was subsequently administered in addition to oral steroids because the patient experienced recurrent symptom flares that were difficult to control with steroid therapy alone. This combination therapy allowed gradual tapering of the daily steroid dose. Clinicians should consider VEXAS syndrome and perform genetic testing when encountering refractory neutrophilic dermatosis or vasculitis accompanied by systemic inflammatory symptoms. Skin Research, 24 : 321-327, 2025