Direct Immunofluorescence for Dermatologic Disorders:A Single-Center Retrospective Analysis for 11 Years / 대한피부과학회지

Background@#Direct immunofluorescence (DIF) is a histochemical technique used to detect tissue-bound autoantibodies and diagnose various immune-mediated skin diseases. @*Objective@#This study aimed to evaluate the sensitivity of DIF for each disorder, and the consistency between clinical, histopathological, and DIF results. @*Methods@#A retrospective study was conducted in 194 patients who underwent skin biopsy and DIF testing at our hospital between January 2011 and December 2021. An antibody panel against immunoglobulin G (IgG), IgA, IgM, C3, C1q, and fibrinogen was used. The concordance rate and κ-coefficient between the clinical, histopathological, and DIF results were evaluated. @*Results@#DIF was observed to be positive in 87 cases; 51 cases of immune-mediated bullous diseases, seven cases of connective tissue diseases (CTDs), 25 cases of vasculitis, and four cases of other diseases. The overall sensitivity of DIF for immune-mediated bullous diseases was 71.8%, which was higher than that of histopathology (64.8%). In CTDs and vasculitis, the overall sensitivities of DIF were 30.4% and 65.8%, respectively, which were lower than those of histopathology (73.9% and 84.2%, respectively). In addition, good concordance among the clinical, histological, and DIF results was observed. @*Conclusion@#DIF is a useful diagnostic method, especially for immune-mediated bullous diseases, lupus erythematosus, and Henoch-Schonlein purpura. However, in other CTDs and vasculitis cases, the sensitivity of DIF is relatively low. Therefore, the diagnostic value of DIF along with clinical and histopathological findings will be maximized only when the DIF test is performed for appropriate diseases.

Spontaneous Improvement of Eosinophilic Dermatosis of Hematologic Malignancy Concurrent with Follicular Lymphoma after Rituximab and Bendamustine Therapy / 대한피부과학회지

Eosinophilic dermatosis of hematological malignancy (EDHM) is a rare condition associated with various hematologic malignancies, characterized by pruritic skin eruptions. We present a case of a 66-year-old woman with follicular lymphoma who developed urticarial and vesicular lesions indicative of EDHM following chemotherapy.The diagnosis was confirmed through histological analysis, revealing eosinophilic infiltration. Treatment included additional chemotherapy sessions and topical corticosteroids, resulting in complete resolution of skin lesions and lymphoma. EDHM requires careful differentiation based on clinical and histological findings. The pathogenesis remains unclear, but addressing underlying hematologic malignancies appears crucial in management. Early recognition of EDHM is essential for appropriate intervention due to its limited therapeutic options.

Missense Variant c.3301C>T (p.R1101W) in von Willebrand Factor A Sequence in a Patient with Recessive Dystrophic Epidermolysis Bullosa Pruriginosa with Compound Heterozygous COL7A1 Variants

Dystrophic epidermolysis bullosa (DEB) pruriginosa is a rare subtype of DEB characterized by multiple, violaceous, and severe pruritic lichenified nodules along with blisters. Here, we report the case of a Korean male who, since the age of 3 years, had multiple pruritic nodules with blisters on both lower extremities. Genetic testing is required to diagnose DEB pruriginosa because its clinical and histologic features are inconclusive. We identified compound heterozygous COL7A1 variants of c.5797C>T (p.R1933*) and c.3301C>T (p.R1101W) in the patient, leading to a diagnosis of recessive DEB pruriginosa. Among the variants identified, c.3301C>T is a novel missense variant that has not been reported previously. This variant is in exon 26, which encodes von Willebrand factor A (vWFA) in collagen type VII. vWFA is known to preserve normal dermal structures by interacting with dermal collagens and basement membranes. Considering that this variant contradicts the general concept that autosomal dominant inheritance is more common and that variants typically occur in the triple helical collagenous domain of COL7A1 in DEB pruriginosa, we focus on the rarity of this case and the possible pathogenic role of the c.3301C>T (p.R1101W) variant.

A Case of Blastic Plasmacytoid Dendritic Cell Neoplasm with Mutations in DNMT3A, TET2, SRSF2, and ATRX Genes / 대한피부과학회지

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive lymphoma with an overall incidence of 0.04 cases per 100,000 people. BPDCN is a hematopoietic clonal neoplasm that originates from plasmacytoid dendritic cell precursors. A 63-year-old man presented with multiple erythematous nodules over his whole body, including his face, trunk, and both upper and lower extremities that appeared 1 month ago. Skin biopsy showed diffuse dermal infiltration by monomorphic atypical lymphocytes with large, irregular nuclei and scant cytoplasms. Immunohistochemical staining was positive for CD4, CD56, and CD123. The karyotype test showed abnormalities in male chromosomes 47, XY, ＋8 [2]/46, and XY [25], and mutations in DNMT3A, TET2, SRSF2, and ATRX genes were identified in a next-generation sequencing (NGS)-based acute myeloid leukemia gene panel test. The patient was diagnosed with BPDCN and treated with a KALLA 1406 regimen; however, he died on the 17th day of treatment.

Rapidly Progressive Myxoinflammatory Fibroblastic Sarcoma with Sudden Onset Treated by Wide Excision: A Case with an Atypical Clinical Course / 대한피부과학회지

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare neoplasm that is frequently located in the distal extremities. Emerging evidence suggests that MIFS can also affect the proximal limbs, trunk, and scalp, and aggressive clinical courses have been noted. We report a case of MIFS that occurred suddenly in the patient’s forearm and grew rapidly within 2 weeks. A level of Ki-67 was observed in the patient’s lesion, which constitutes a considerable finding compared with most MIFS cases. The patient underwent surgical tumor removal, and no evidence of recurrence was noted. We highlight this case in view of its sudden occurrence and rapid local progression, which contradicts the usual features of this disease, suggesting that this clinical course might be attributable to the high Ki-67 value.