Elastosis perforans serpiginosa (EPS) is a rare condition that belongs to the group of acquired perforating dermatosis. It usually appears as keratotic papules in serpiginous configuration with central atrophy on the head, nape, and extremities. It is characterized by the transepidermal elimination of elastic fibers with clumping and vertical orientation of elastic fibers. In many cases, it is associated with genetic or connective tissue diseases. A 26-year-old female patient with Down syndrome presented with brownish keratotic papules on both arms. The lesion had been present for 2 years, but there were no symptoms. The biopsy specimen showed transepidermal elimination of the degenerated elastic fibers. Verhoeff elastic staining revealed an increased number of thick elastic fibers. Based on these findings, the patient was diagnosed with EPS. Treatment with CO 2 laser was performed with a successful outcome.

Tuberculous lymphadenitis is among the most frequent presentations of extrapulmonary tuberculosis; the most common presentation is isolated chronic non-tender lymphadenopathy in young adults without systemic symptoms. Dupilumab is a fully human monoclonal antibody directed against interleukin-4 receptor-α that blocks the synergistic effects of interleukin-4 and interleukin-13 on allergic inflammation. Its well-known adverse events are allergic conjunctivitis, injection site reaction, and dupilumab facial redness. A 32-year-old female with severe atopic dermatitis was treated with dupilumab for 2 months at our clinic. She complained of multiple enlarged palpable lymph nodes on the right side of the neck and inguinal area for 2 months. Laboratory tests showed an increased total eosinophil count and immunoglobulin E level, as well as positive interferon-γ release assays. Radiological examination showed multiple low echoic and heterogeneous well-enhancing lymph nodes in level II, III, IV, and V of the neck. Histological examination revealed caseous necrosis and tuberculoid granuloma. The lymph node enlargements were completely relieved after antituberculosis treatment. The mechanism for the development of tuberculous lymphadenitis in a patient receiving dupilumab is not fully understood yet. In some previous studies, treatment with dupilumab suppressed the expression of genes related not only to T helper 2 and eosinophil response but also to proinflammatory responses. It could not inhibit the intracellular growth of Mycobacterium tuberculosis in macrophages, predisposing them to the development of tuberculous infection. To the best of our knowledge, this is the first report on the development of tuberculosis lymphadenitis in a patient treated with dupilumab.

Kaposi sarcoma (KS) is a vascular and lymphatic neoplasm caused by human herpesvirus 8 (HHV-8). AIDS-related KS has variable clinical courses ranging from mild disease presenting as an incidental finding to severe disease presenting as an aggressively progressing neoplasm that can lead to poor prognosis or even death. Typical clinical manifestation of KS is known as multiple cutaneous lesions on the extremities, trunk, and face with mucosal involvement. A 46-year-old male with AIDS complained of an erythematous patch on the right forearm which appeared 5 months ago. For a year, he was treated with antiretroviral drugs for AIDS. Physical examination revealed a 2.5-cm solitary erythematous patch only on the right forearm. Laboratory data revealed human immunodeficiency virus (HIV)-1 RNA of less than 40 copies/ml and a CD4 cell count of 264 cells/mm 3 . Histological examination revealed numerous slit-like spaces and vascular proliferation with primitive blood vessels dissecting between the collagen bundles and the dermis. Immunohistochemical staining showed positive HHV-8 nuclear staining of spindle cells. The histological features and positive HHV-8 immunohistochemical stain were consistent with the diagnosis of early patch stage of AIDS-related KS. KS can readily be misdiagnosed in early patch stage even by experienced clinicians, which leads to requirement of pathologic determination. On close inspection, it can be distinguished from other mimickers by its distinctive histologic features and immunohistochemical staining for HHV-8. Therefore, in cases of HIV-positive patients with clinically or histologically vascular-appearing mucocutaneous lesions, KS should be considered as a possible differential diagnosis.

Renal cell carcinomas (RCC) account for 2.4% of all adult malignancies. RCC is known for its aggressive nature, with approximately one-third of patients presenting with metastasis at the time of diagnosis. Cutaneous metastasis is a rare presentation of this cancer. A 78-year-old male presented with numerous erythematous nodules of various sizes on the left flank, which he had had for a month. He had undergone a left partial nephrectomy for papillary RCC 3 years previously and had been receiving chemotherapy since surgery. Histopathology revealed papillary architecture with prominent atypical nucleoli throughout the dermis. Immunohistochemical findings were positive for CD10, cytokeratin 7, PAX-8, vimentin, and alpha-methylacyl-CoA racemase. These results led to a diagnosis of cutaneous metastases of papillary renal cell carcinoma. Papillary RCC rarely presents with cutaneous metastases.Because these lesions are easily accessible, cutaneous lesions in patients with risk factors for RCC should be excised and pathologically evaluated.

Background: Since the disease burden of atopic dermatitis (AD) understandably increases with its disease severity, studies, especially on the baseline characteristics of severe AD, have been conducted in some countries to deepen the understanding of the disease and, by extension, formulate a relevant national policy. However, research on the baseline characteristics of severe AD in Korea remains insufficient. Objective: To report the baseline demographics and describe the clinical characteristics of adult Korean patients with severe AD, including medical and treatment history, clinical manifestations, disease severity, and laboratory findings, in order to understand the characteristics of severe AD. Methods: A single-center, prospective, non-interventional, observational, longitudinal study of 108 patients with severe AD was conducted between January 2021 and December 2022. Clinical data and patient-reported measures of signs and symptoms of AD were recorded at baseline. Results: The mean Eczema Area and Severity Index score of the patients was 28.5±6.8. The mean pruritus numerical rating scale, Patient-Oriented Eczema Measure, Dermatology Life Quality Index, and Atopic Dermatitis Control Tool scores were 8.1±1.7, 23.6±4.8, 21.9±6.6, and 19.5±3.9, respectively. Although a larger proportion of the headeck and trunk are affected than both limbs, the key signs of AD were less severe in the headeck region than in the other regions. Erythema and lichenification were more representative clinical signs of severe AD than induration and excoriation. The baseline data on previous treatments reflected the AD treatment guidelines in Korea. Conclusion This real-world data will provide dermatologists with a better understanding of severe AD, which will eventually lead to better clinical and health policy decisions for patients with severe AD.