A 42-year-old female was referred to our hospital with a left vulval mass that she had rst noticed six months earlier and had been gradually increasing in size. A 5 cm subcutaneous mass with no adhesion to the lower oor and mild redness on the skin surface was found on the left vulva. T1- weighted MRI revealed that the mass mostly consisted of areas with equal signal to the muscle and parts that showed high signal. Fat suppression imaging showed low signal intensity. Histopathological examination revealed proliferation of mature adipocytes, collagen bers, and CD34- positive spindle cells. The present case was diagnosed as spindle cell lipoma (SCL). SCL is a subtype of lipoma that commonly occurs in the neck, back, and shoulders of middle-aged and older men. Female vulva onset has not previously been reported in Japan and such cases are extremely rare. Skin Research, 22 : 276-280, 2023

A 50-year-old man had a COVID-19 infection after a live kidney transplant for diabetic nephropathy. The patient was taking oral immunosuppressive drugs. He became seriously ill and was put on a ventilator. His symptoms improved, and he was transferred to another hospital. Redness,swelling, and heat sensations appeared in his right cheek at his rst visit. CT revealed a diagnosis of right cheek cellulitis due to the spread of inammation from the right acute sinusitis. He was referred to the otorhinolaryngology department in our hospital for sinus surgery and left hemiplegia that appeared after surgery. While he was being treated for cerebral infarction of unknown onset,mucor was detected in the sinuses. Skin biopsy was performed revealing rhinocerebral zygomycosis with cerebral infarction. Amphotericin B administration reduced the inammatory response ; however, the cerebral infarction area expanded. The patient died within a month. In immunosuppressed patients, skin biopsy should be aggressively performed to identify similar pathogenic diseases. Skin Research, 22 : 281-285, 2023

An 80-year-old male presented with diffuse, itchy, and tense blisters. He had a history of urothelial carcinoma, diabetes mellitus, and chronic renal dysfunction. Based on the histopathological and direct immunouorescence features of the lesions and his increased antiBP180 antibody level, we diagnosed him with bullous pemphigoid (BP). His BPDAI score indicated severe disease, and oral prednisolone (PSL, 60 mg/day) was administered following steroid pulse therapy (methylprednisolone). As the patient had urothelial carcinoma, we did not administer immunosuppressive drugs. Early PSL reduction was necessary due to the patient’s social history. Following plasma exchange therapy, rituximab was administered. Subsequently, his anti-BP180 antibody level decreased, and clinical symptoms improved. He was discharged after early PSL reduction. BP predominantly affects the elderly. PSL administration often leads to adverse effects due to the patients’social history. Although rituximab for BP is currently not covered by insurance,it is effective for use in refractory patients with social problems or drug restrictions. Skin Research, 22 : 286-291, 2023

An 80-year-old man had been treated with oral antibiotics for his right lower leg cellulitis at a previous hospital for seven days prior to his rst visit to our department. Two years earlier, he had been diagnosed with classic Kaposi’s sarcoma in both lower legs at another hospital. His symptoms of cellulitis did not improve, and he was referred to our hospital. He had been experiencing leg pain for three years. Physical examination revealed grayish-brown macules with partial inltration of the bilateral lower legs and dark red macules on the plantar surfaces of the feet. Histopathological ndings demonstrated nodular growth of basophilic tumor cells in the dermis, accompanied by surrounding vascular growth. Immunohistopathological ndings indicated that the tumor cells were HHV-8 positive. He had no HIV infection and was not using immunosuppressive drugs. Based on these ndings, we diagnosed him with classic Kaposi’s sarcoma. Various treatments for classic Kaposi’s sarcoma, including radiotherapy, imiquimod, and others, are available, but no clear evidence supports their efcacy. When treating patients with classic Kaposi’s sarcoma, we should consider their background and the slow progression of the disease. Skin Research, 22 : 292-297, 2023

An 85-year-old man who was a resident of a care facility was transported to our emergency department because of impaired consciousness. He required intubation before being admitted to our intensive care unit (ICU). Upon examination following admission to the ICU, pale erythematous lesions were observed on the right lower extremity and the right inguinal region. Gram-positive cocci were detected in his blood cultures, and he was diagnosed with bacteremia caused by cellulitis in his lower right leg. It was determined that the loss of consciousness was due to hypoxic septic encephalopathy or acute symptomatic seizures resulting from sepsis. Treatment with antibiotics was initiated, and the causative agent was identied as Streptococcus dysgalactiae subsp. equisimilis (SDSE). The administration of antibiotics and anticonvulsants led to the amelioration of the cellulitis affecting the patient’s right lower extremity, along with the accompanying disturbance of consciousness. SDSE infections are more frequent in older individuals and can be severe in those with comorbidities. Sepsis can lead to impaired consciousness and cellulitis can also result in such symptoms. Dermatologists should be aware that even apparently mild cases of cellulitis can result in consciousness disorders. Skin Research, 22: 298-302, 2023

A 65-year-old diabetic male patient was referred to our department because of the appearance of itchy papules on his extremities that had not improved since about 2 months prior to his initial visit. He had caught and brought with him insects found in his bedroom. The insects were identied as bed bugs, and he was diagnosed with bed bug bites. He was treated with topical steroids and the bed bugs were exterminated ; however, the skin rash showed little improvement. Sarcoptes scabiei were detected on his ngers and scabies was diagnosed as a further complication. Scabies improved with administration of topical phenothrin ; however, pruritic papules remained. We examined the papules with skin biopsy. Histopathological examination revealed cup-shaped ulcers with adherent crusts and inammatory cell inltration in the dermis, and trans-epidermal elimination of collagen bers in some areas, leading to a diagnosis of acquired reactive perforating collagenosis (ARPC). After thorough eradication of bed bugs with insecticides and topical steroids combined with excimer light irradiation, the eruptions were markedly improved. Cases with bed bug bites are on the increase in Japan and continue to spread. If the patient is diagnosed with unexplained insect bites,the possibility of bed bug bites should be considered. The pathogenesis of ARPC is still largely unknown, but it is thought to be a complex condition with changes due to comorbidities. Insect bites with severe itching, as in the present case, may be a trigger for ARPC. It is desirable to treat not only the skin rash but also to take measures against insect bites and provide patient guidance. Skin Research, 22 : 303-308, 2023

Biological therapy has been associated with numerous side effects, particularly infections. Interstitial pneumonia (IP) is increasingly being reported as an adverse reaction. A 64-year-old woman received secukinumab for pustular psoriasis treatment. However, she developed IP and elevated Krebs von den Lungen-6 (KL-6) levels. The IP was believed to be caused by secukinumab and treatment was discontinued. Although KL-6 levels improved, the patient experienced a recurrence of the skin rash. Guselkumab was introduced, which improved the skin rash and maintained KL-6 levels without IP relapse. This case highlights a possible link between psoriasis and IP, particularly when KL-6 levels increase following biological therapy. Thus, it is essential to distinguish between the four types of IP : false-positive, infection-caused, psoriasis-associated, and drug-induced IP due to biological agents. In cases of false-positive IP, regular follow-up is essential due to the possibility of microalveolar damage, even without evidence of IP. In cases of psoriasisassociated IP, increasing the drug dose may alleviate the skin rash and IP, making it crucial to differentiate it from drug-induced IP, for which discontinuing the biological agent is necessary and switching to a different therapeutic agent may be unsafe. It is also essential to carefully assess elevated KL-6 levels in patients with concomitant malignancy, as KL-6 levels can increase in lung,breast, and pancreatic adenocarcinomas and squamous cell carcinoma of the lung. Evaluating psoriasis disease status, performing human surfactant protein D measurement, imaging studies, and considering whether the patient can continue receiving biologics are important. Skin Research, 22 : 309-314, 2023

Platelet-rich plasma (PRP) therapy promotes tissue regeneration and wound healing using growth factors and cytokines in platelets concentrated by centrifugation. It has been used in bone regeneration treatment in the elds of oral surgery, orthopedics, cosmetic medicine, and anti-aging medicine. It has been covered by health insurance as the rst regenerative medicine procedure in Japan since 2020, which provided a new treatment option for refractory skin ulcers. Herein, we present the results of PRP therapy for ve cases with refractory skin ulcers due to venous stasis dermatitis, systemic sclerosis, and vasculitis in our hospital. Four of the ve cases showed the reduction of ulcer size or epithelialization. Although the skin ulcers were refractory and did not rapidly epithelialize, PRP therapy showed a partial efcacy. The remaining case was treated with only one course due to wound infection or poor control of necrotic tissue of the ulcer. Although PRP therapy requires a centrifuge and a process for separating platelet components, the procedure is easy to perform and requires little burden for patients as only blood collection is necessary. Our ndings suggest that PRP therapy is an effective treatment for skin ulcers refractory to topical treatments. Skin Research, 22: 315-321, 2023