Degos disease, also referred to as malignant atrophic papulosis, was first described in 1941 by Köhlmeier and was independently described by Degos in 1942. Degos disease is characterized by diffuse, papular skin eruptions with porcelain-white centers and slightly raised erythematous telangiectatic rims associated with bowel infarction. Although the etiology of Degos disease is unknown, autoimmune diseases, coagulation disorders, and vasculitis have all been considered as underlying pathogenic mechanisms. Approximately 15% of Degos disease have a benign course limited to the skin and no history of gastrointestinal or central nervous system (CNS) involvement. A 29-year-old female with history of systemic lupus erythematosus (SLE) presented with a 2-year history of asymptomatic lesions on the dorsum of all fingers and both knees. The patient had only skin lesions and no gastrointestinal or CNS vasculitis symptoms. Her skin lesions were umbilicated, atrophic porcelain-white lesions with a rim of erythema. On the basis of clinical, histologic, and laboratory findings, a diagnosis of Degos-like lesions associated with SLE was made. The patient had been treated for SLE for 7 years. Her treatment regimen was maintained over a 2 month follow-up period, and the skin lesions improved slightly with no development of new lesions.

Desmoplastic fibroblastoma is a vary rare subcutaneous proliferation. We describe a case of desmoplastic fibroblastoma in a 24-year-old Korean woman who presented with a 2.5 cm solitary and firm nodule on her back which had been present for 3 months. Histologic studies showed a well demarcated subcutaneous tumor composed of stellate or spindle shaped cells embedded in hypovascular fibrous or fibromyxoid stroma. No mitotic figures, calcification, or necrosis were observed. The stellate or spindle shaped cells were positive for vimentin. The stroma stained positively with Alcian blue and Masson trichrome. S-100 protein, actin, desmin, and elastic fiber stains were all negative in the stellate or spindle shaped cells. There has been no recurrence or metastasis of the tumor over an 18-month follow-up.

Spark's nevus is a compound word composed of Spitz nevus and Clark's nevus. It is one of the combined melanocytic nevi which is more common in female and usually presents as a sharp circumscribed hyperpigmented macule on the lower extremities. On histopathologic findings, both cytologic features of Spitz nevus characterized as large spindle or epithelioid melanocytes containing large nuclei with abundant cytoplasm, and architecture of Clark's nevus characterized as elongation of rete ridges, bridging of the nests, concentric and lamellar fibrosis can be seen. A 24-year-old female presented with an asymptomatic, solitary, dark-brown-colored papule surrounded by brownish patch that looked similar to dysplastic nevus or malignant melanoma on the buttock. On dermoscopic examination, it showed brown-to-black globules, diffuse homogenous pigmentation with blue-white structures, and a surrounding brownish reticular pattern that faded away. On histopathologic findings, overall asymmetrical structure, epithelioid large melanocytes containing large nuclei with abundant cytoplasm, and Kamino body were seen in the central portion. Also, lentiginous hyperplasia, bridging of the nests composed of melanocytes containing foamy cytoplasm, concentric and lamellar fibrosis along with the elongation of rete ridge, and perivascular lymphocytic infiltration were seen in the peripheral portion. The diagnosis of Spark's nevus was made. Following its definition, this combined nevus is diagnosed histopathologically, but the clinicodermoscopic features have not been well described. Herein, we report a case of Spark's nevus in which dermoscopy was helpful for differentiating it from malignant melanoma. (Ann Dermatol 32(3) 233∼236, 2020

BackgroundTsutsugamushi disease is an acute, febrile, infectious disease caused by Orientia tsutsugamushi. Several studies investigating the histopathologic findings of eschars in tsutsugamushi disease reported leukocytoclastic vasculitis and neutrophil infiltration as the major findings. However, these findings may result from secondary changes following tissue necrosis. The histopathologic findings of perieschar lesions may be important to understand the primary changes associated with tsutsugamushi disease.ObjectiveTo investigate characteristic histopathologic features of perieschar lesions and suppose the mechanism of vascular pathophysiological changes associated with tsutsugamushi disease.MethodsWe analyzed histopathological slides of perieschar lesions in 12 patients diagnosed with tsutsugamushi disease.ResultsIn the epidermis, exocytosis of mononuclear cells (75.0%) and basal vacuolar changes (66.7%) were frequent. In the dermis, perivascular, interstitial, and perineural mononuclear cell infiltration (100.0%, 83.3%, and 83.3%, respectively), as well as thrombosis (83.3%), atypical lymphocyte infiltration (91.7%), and mitotic figures (83.3%) were commonly seen. Lymphocytic vasculitis and mononuclear cell infiltration around eccrine glands were found in all cases, but eosinophil infiltration was only found in one patient (8.3%). However, the characteristic findings of eschar lesions, such as leukocytoclastic vasculitis and neutrophil infiltration, were not found in perieschar lesions.ConclusionThe major histopathologic findings in the perieschar lesions of tsutsugamushi disease were lymphocytic vasculitis and atypical lymphocytic infiltration, mimicking lymphoma. Therefore, we suggest that this lesion should be added to the list of pseudolymphomas. To observe these characteristic histopathologic features, we also recommend that skin biopsies should be performed on perieschar lesions, not eschar lesions.

BackgroundFolliculotropic mycosis fungoides (FMF) is a variant of mycosis fungoides (MF) that is characterized clinically by variable types of skin eruptions, including plaques, acneiform lesions, and alopecic patches. Histopathologically, FMF is characterized by folliculotropic infiltrates.ObjectiveThis study was conducted to scrutinize the clinical and histopathologic features of FMF in Koreans and the responses to phototherapy.MethodsTwenty Koreans diagnosed with MF who had histopathologic evidence of folliculotropism were enrolled.ResultsEighteen patients had head-and-neck-region infiltration, while five had solitary lesion. In all patients, the atypical lymphocytic infiltrate had a perifollicular distribution. Twelve patients were treated with ultraviolet A (UVA)-1. Eleven of these 12 patients with early-stage FMF experienced >80% improvement (8: complete remission; 3: partial remission). Four patients, including 2 who relapsed after UVA-1, were treated with photodynamic therapy (PDT), reaching complete remission after PDT.ConclusionAs FMF has variable clinical presentations, skin biopsy is required to confirm the diagnosis. And both UVA-1 and methyl aminolevulinate-PDT are clinically effective in treatment of early-stage FMF.