A 51-year-old man (Case 1) with a 30-year history of smoking, experienced repeated bilateral finger pain during winter, beginning three years earlier. He received oral medication at the clinic ; however, his symptoms did not improve. The patient was admitted to our hospital. Based on characteristic CT angiography findings, we diagnosed the patient with Buerger disease. Drug therapy, including vasodilators, did not improve his symptoms. The patient was successfully treated with a stellate ganglion block. The patient remained in remission even after transitioning to spinal cord stimulation. A 71-year-old woman (Case 2) had no history of smoking. She had been taking rivaroxaban for deep vein thrombosis for two years. She visited our hospital because of pain and discoloration of her right thumb, index, and middle fingers. Antiphospholipid syndrome was suspected ; however, the diagnosis could not be confirmed. We diagnosed the patient with non-arteriosclerotic chronic arterial occlusive disease. Antithrombotic drugs were discontinued due to the development of a subdural hematoma. Similar to Case 1, the patient improved with a stellate ganglion block and remained in remission after switching to spinal cord stimulation. Chronic arterial occlusive disease is primarily caused by arteriosclerosis obliterans and diabetic foot lesions ; therefore, opportunities to treat non-arteriosclerotic conditions are relatively rare. Moreover, non-arteriosclerotic conditions, such as Buerger’s disease, are often challenging to manage due to limited treatment options and their refractory or recurrent nature. Spinal cord stimulation is an emerging therapy that is reported to improve microcirculation continuously by indirectly reducing sympathetic nerve tension. This approach is less invasive than sympathectomy and reversible, making it a valuable treatment option for ischemic limbs refractory to drug therapy. Skin Research, 24: 1-8, 2025

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We present the case of a 33-year-old female with xanthogranuloma comprised of lymphoid follicles. One year prior to her visit to our hospital, she noticed an induration on the right side of her chest. The induration gradually enlarged, and the patient experienced slight tenderness, prompting her to seek medical attention at our hospital. At the first visit to our hospital, a movable, elastic, hard subcutaneous induration approximately 2 cm in size was observed, accompanied by tenderness. Ultrasound and MRI examinations were performed, but a definitive diagnosis could not be made. We performed surgical excision of the induration. Histopathological examination revealed xanthogranuloma composed of lymphoid follicles without necrosis. Based on immunohistochemical findings, the lymphoid follicles were diagnosed as reactive. We hypothesized that the lymphoid follicles were caused by chronic inflammation. Xanthogranuloma comprised of lymphoid follicles without necrosis is rarely reported. We report our case and review the literature. Skin Research, 24: 9-13, 2025

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A 51-year-old male patient experienced repeated periods of prolonged bed rest for approximately one month due to the exacerbation of anxiety neurosis. The symptoms had begun six months prior to his initial visit. Three months before his first visit, the patient became aware of a soft, tender subcutaneous mass in the sacral region, which gradually increased in size. He was referred to our department for further evaluation. MRI revealed a subcutaneous mass on the sacral fascia with low signal intensity on both T1-weighted and T2-weighted images, without any fat-suppressed changes. Histopathological examination following total resection showed a nodule in the deep dermis and subcutis. The nodule contained central necrotic areas with fibrinoid metaplasia and a lack of cellular components, surrounded by granulomatous changes with vascularization, edematous stroma, fibrosis, and cellular pleomorphism. Immunohistochemical staining and special stains showed diffuse positivity for vimentin, partial positivity for alcian blue and α-SMA in some areas, and negativity for S-100 and CD34, leading to a diagnosis of ischemic fasciitis. This condition is most commonly seen inelderly and bedriddenpatien ts ; however, it is rare inhealthy adults. Recently, cases have been reported in younger patients. To diagnose this disease, it is important to inquire about episodes of chronic pressure overload during the patient interview and perform a histopathological examination. Skin Research, 24: 14-19, 2025

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Extramammary Paget’s disease (EMPD) is usually treated with resection with adequate margins. In addition to the removal of the anus or urethra, the creation of an artificial anus or changes to the urinary tract may occasionally be necessary. However, these interventions significantly reduce the patient’s quality of life. Although unresectable EMPD is sometimes treated with radiotherapy, there are few reports on its use. As a result, the significance of radical radiotherapy in the treatment of EMPD has not been established. Herein, we describe 15 cases of EMPD treated with radiotherapy. Although all patients were candidates for total resection, they opted for radiotherapy either due to personal preference or dementia. The mean age was 80.1 years, and the male-to-female ratio was 4 : 11. The average radiation dose was 55.4 gray, and the average duration of follow-up was 30.9 months. In all cases, the involved lesions grossly resolved within six months. Duringthe course, five patients experienced recurrence (average of 16. 8 months). Of these patients, three did not experience recurrence after additional irradiation or local excision, one died of metastasis to the liver and abdominal lymph nodes, and one died of concomitant peritonitis after cystourethrectomy for urethral invasion. Radiotherapy is considered beneficial for patients with EMPD who are unwilling to undergo aggressive surgery to maintain quality of life. As the recurrence rate is relatively high, long-term follow-up is necessary after radiotherapy. Skin Research, 24: 20-26, 2025

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A 28-year-old woman visited her previous physician for abdominal pain 4 months before her first visit to our department and was diagnosed with appendicitis by abdominal CT. At that time, a nodule shadow was observed in the right kidney, and she was referred to our Nephrologic and Urologic Surgery department. During a visit to the urologist, she complained of skin rash on her anterior chest and forearms. She was then referred to our department. Small, scattered erythema was observed on the anterior chest and left forearm. Histopathological examination confirmed irregular proliferation of spindle-shaped cells in the upper dermis. Immunohistochemical findings showed that the spindle-shaped cells were α-SMA (＋) and desmin (＋), which led to the diagnosis of multiple piloleiomyomas. The lesion was mildly itchy and tender, but the patient declined treatment and opted for follow-up care. Cutaneous leiomyoma is a benign tumor that arises from smooth muscle cells and typically has a good prognosis. However, multiple piloleiomyomas, a form of cutaneous leiomyoma, can be associated with complications such as uterine myoma or renal cell carcinoma, a condition known as hereditary leiomyomatosis and renal cell cancer (HLRCC). Renal cell carcinoma associated with HLRCC progresses rapidly and carries an extremely poor prognosis. A definitive diagnosis of HLRCC requires the identification of a mutation in the gene encoding fumarate hydratase (FH). In our case, no FH mutation was identified. Patients with multiple piloleiomyomas should be carefully monitored for potential complications, including uterine fibroids and renal cell carcinoma. Skin Research, 24: 27-32, 2025

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A 74-year-old Japanese man presented with erythema of his head, neck, and both thighs ; Gottron’s signs ; muscle weakness in proximal muscles ; elevated serum level of CK ; electromyographic changes ; presence of anti-TIF1-γ antibody ; and pathological findings of myositis on muscle biopsy. This led to the diagnosis of anti-TIF1-γ antibody-positive dermatomyositis. Lower gastrointestinal endoscopy showed type 2 advanced cancer in the rectal region. Since hoarseness also developed, early therapeutic intervention was deemed necessary, and prednisolone (PSL) was initiated at a dose of 80 mg/day. Approximately two weeks later, the dose was tapered to 20 mg/day over the course of one week in preparation for rectal cancer surgery. The plan was to return the PSL dosage to 80 mg/day after the surgery, but this was not required due to the improvement in serum levels of CK and aldolase. In dermatomyositis complicated by malignancy, it is generally recommended that the treatment of the malignancy should take precedence, provided that the treatment of myositis is not urgent. Among the reported cases of anti-TIF-1γ antibody-positive dermatomyositis complicated by malignancy, only two cases have been reported in which treatment with PSL was initiated prior to tumor resection. Based on the course of the present case, the appearance of dysphagia or hoarseness as a sign of dysphagia may suggest that initiation of PSL should precede tumor resection. Further case studies are needed to establish a protocol and determine the optimal timing of treatment for dermatomyositis complicated by malignancy. Skin Research, 24: 33-39, 2025

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A 62-year-old man visited our hospital due to a subcutaneous nodule on his left cheek, accompanied by redness and a burning sensation. Ultrasonography showed a well-defined, mosaic-like hypoechoic tumor, with posterior echo enhancement, lateral shadow, and mild internal blood flow. MRI showed low signal on both T1- and T2-weighted imaging in the deep part of the tumor. The superficial part of the tumor was divided into slightly low and equal signal areas on T1-weighted imaging and showed high signal on T2-weighted imaging. We diagnosed the patient with atheroma and performed local excision after the signs of infection improved. Histopathologically, atypical epithelial cells were found, which proliferated in a cribriform and micropapillary pattern. Tumor cells were floating in the retained mucus. Based on these findings and the absence of primary lesions in other organs, we diagnosed the patient with cutaneous mucinous carcinoma. We then performed a second local excision and sentinel lymph node biopsy. No residual tumor cells were found in the additional excision specimen, and there was no metastasis in the sentinel lymph node. No local recurrence nor metastasis has been observed for 3 years post-surgery. Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a differential diagnosis for cutaneous mucinous carcinoma. Recently, the concept that EMPSGC is a precursor to cutaneous mucinous carcinoma has been proposed. Based on the results of HE staining and immunohistochemical analysis, it is possible that our case represents cutaneous mucinous carcinoma derived from EMPSGC. Imaging tests, such as ultrasonography and MRI, are useful to evaluate the size, depth, and internal characteristics of the tumor before excision. Cutaneous mucinous carcinoma is often misdiagnosed as atheroma. When inconsistencies, such as tumor heterogeneity observed on MRI, are noted in cases of suspected atheroma, as seen in the present case, it is advisable to consider performing skin biopsies before performing excision. Skin Research, 24: 40-46, 2025

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A 76-year-old Japanese male with Castleman disease and autoimmune hemolytic anemia had been treated with rituximab (2,800 mg in total), tocilizumab (1,200 mg in total), and prednisolone (60.0 mg/day to 17.5 mg/day for nearly 4 years). He complained of edema of the left upper limb and skin ulcers on the left elbow and right shoulder. He was diagnosed with a cutaneous non-tuberculous mycobacterial infection. The causative agent was identified as Mycobacterium shigaense. This bacterium is a relatively new and rare non-tuberculous mycobacterium that was first reported in Shiga Prefecture in 2009. This case is the 10th reported case. Since it is phylogenetically close to M. simiae, it may have been misidentified until now. Of the 10 cases reported, includingour own case, the patient’s place of residence has been confirmed as beingShig a Prefecture in five cases, suggesting a very high regional characteristic. There have also been three reported cases in Osaka Prefecture. The bacterium was isolated from the water of Yodo River in Osaka, the only river that flows out of Lake Biwa in Shiga Prefecture. The pathogenicity is unclear ; however, in this case, immunosuppression and the use of biological agents were considered risk factors for its onset. Since this bacterium has a different antibiotic susceptibility profile to M. simiae, it is important to recognize it as an unclassifiable non-tuberculous mycobacterial infection. Skin Research, 24: 47-51, 2025

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A 53-year-old Japanese female presented to our hospital with a well-defined elevated lesion on the right side of her parietal region. She had a habit of scratching the area. The lesion was tender with palpable induration within the nodule, but there were no signs of infection. Surgical resection of the lesion and full-thickness skin grafting were performed. Histopathological examination revealed a basophilic calcium depositionwith marked collagenhyperplasia around the calcification. Serum calcium and phosphorus levels were within normal limits. There was no underlying disease such as parathyroid dysfunctionor collagendisease. Calcium depositionwas observed in histopathological examination. Therefore, we diagnosed this case as dystrophic calcinosis cutis that occurred in the scar. Although cases of burns, pressure ulcers, and trauma have been reported, there was no history to suggest these conditions in our case. Our findings suggest that the lesion was caused by addictive scratching over a long period of time. Skin Research, 24: 52-55, 2025

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A 77-year-old woman visited a nearby dentist with the main complaint of swelling of the left cheek. She was suspected of having left parotitis and antibiotic treatment was initiated ; however, there was no improvement. She was referred to the oral surgery department of our hospital. CT revealed significant enlargement of the left parotid gland, and the patient was hospitalized. The patient was diagnosed with purulent parotitis and underwent antibiotic treatment and drainage. However, as the skin ulcer from the drain insertion gradually expanded, daily debridement of the neck was performed. Despite this, the extent of necrosis continued to increase, and the patient was referred to our department. At the time of the first visit to our department, an irregular ulcer with a limbic embankment (11.5×8 cm) was observed on the left side of the neck. Klebsiella pneumoniae ssp. pneumoniae was detected in bacterial culture. Pathological examination of tissues from the ulcer margin revealed a high degree of neutrophil infiltration extending from the epidermis to the subcutaneous tissue. After a diagnosis of pyoderma gangrenosum, oral prednisolone (30 mg/day) and minocycline (200 mg/day) were initiated, leading to rapid ulcer contraction. Pyoderma gangrenosum occurring in the parotid gland and neck is rare. It is necessary for a dermatologist to intervene at an early stage to manage expanding ulcers. Skin Research, 24: 56-60, 2025

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A 77-year-old woman was referred to our department for a growing nodule on her left cheek, which had appeared three months earlier. At the first visit, an 11 mm pale red nodule with smooth surface and telangiectasia was observed on the left cheek. Skin biopsy revealed dense proliferation of small, basophilic tumor cells in the dermis. Immunostaining was positive for CK20, chromogranin A, and Merkel cell polyomavirus, and negative for TTF-1, leading to a diagnosis of Merkel cell carcinoma. No obvious metastases were found in the whole-body search. Due to her advanced age and dementia, neither sentinel lymph node biopsy nor enlarged resection could be performed. Resection was performed with a margin of 5 mm, and postoperative radiation therapy was administered around the primary lesion and in the left cervical lymph node area. No metastasis or recurrence has been observed three years after the surgery. As the prognosis of Merkel cell carcinoma is generally poor, extended resection and sentinel lymph node biopsy are recommended. However, because of its high radiosensitivity, postoperative radiation therapy may reduce the risk of recurrence even in cases where sufficient margins are not available, as in this case. Skin Research, 24: 61-65, 2025

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A 37-year-old female was admitted to our hospital for treatment of an infection associated with AQUAlift○R, a non-absorbable filler used for breast augmentation. During the hospitalization, she developed hypoalbuminemia, systemic edema, and bilateral pleural effusion. The hypoalbuminemia worsened despite the apparent resolution of the infection. Histopathological examination of the capsule surrounding the AQUAlift○R revealed strong granulomatous changes. Based on the clinical course and histopathological findings, we suspected human adjuvant disease (HAD) or autoimmune/inflammatory syndrome induced by adjuvants (AISA). AQUAlift○R is a hydrophilic gel consisting of a copolyamide and sodium chloride solution. Although multiple studies have documented intractable complications due to fillers containing copolyamide, to the best of our knowledge, no studies have previously reported an association between these fillers and HAD or AISA. This case suggests that the copolyamide in certain non-absorbable fillers acts as an adjuvant. Furthermore, HAD/AISA induced by non-absorbable fillers may be challenging to treat due to its tendency to infiltrate and migrate into surrounding tissue. Skin Research, 24: 66-73, 2025

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A 55-year-old woman presented to our hospital with a chief complaint of a black nodule on the vulva. A 2 cm-sized mass with partial ulceration was found on the right genital mucosa, and a partial biopsy was performed, which resulted in a diagnosis of mucosal-type malignant melanoma. After extended resection and sentinel lymph node biopsy, the patient was diagnosed with pT4bN2aM0 Stage pIIIC according to the AJCC 8th edition. PD-L1 expression was ＞90%, and the BRAF mutation was wild type. The patient received four courses of pembrolizumab (400 mg/dose) as post-operative adjuvant therapy, but multiple lymph node metastases emerged. Subsequently, she underwent four courses of combination therapy with nivolumab (80 mg/dose) and ipilimumab (135 mg/dose). However, liver metastasis appeared, and the lymph node metastasis increased, leading to her being considered a primary invalid case. She then underwent five courses of transcatheter arterial chemoembolization for liver metastases as well as radiotherapy (80 Gy/20 Fr) for the lymph node metastases. In addition, carboplatin (563 mg/dose) and paclitaxel (298 mg/dose) were administered, which initially reduced the metastases ; however, new liver metastases appeared again. FoundationOne○R gene panel examination revealed a KIT L576P mutation and KIT amplification, which led to the introduction of imatinib (400 mg/day). After starting imatinib, the liver metastases did not increase for 13 months, showing a prolonged prognostic effect. Herein, we report a case of immune checkpoint inhibitor-resistant mucosal melanoma in a patient, where the gene panel examination expanded an effective therapeutic option with the c-kit inhibitor, imatinib. Skin Research, 24: 74-79, 2025

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