Clara Ureña-Paniego, Francisco Vílchez-Márquez, María Narváez-Simón, Elena Masana-Flores, Salvador Arias-Santiago
{"title":"Subcutaneous Panniculitis-Like T-Cell Lymphoma in a 2-Year-Old: Case Report and Literature Review.","authors":"Clara Ureña-Paniego, Francisco Vílchez-Márquez, María Narváez-Simón, Elena Masana-Flores, Salvador Arias-Santiago","doi":"10.1097/DAD.0000000000003070","DOIUrl":"https://doi.org/10.1097/DAD.0000000000003070","url":null,"abstract":"<p><strong>Abstract: </strong>Subcutaneous panniculitis-like T-cell lymphoma is a rare cutaneous T-cell lymphoma characterized by cytotoxic T-cell infiltration of subcutaneous fat that clinically mimics panniculitis. It predominantly affects adults and is rarely present in young children. We report a case of subcutaneous panniculitis-like T-cell lymphoma in a 2-year-old child and review the pediatric literature to highlight the unique clinical features and outcomes in this age group.</p>","PeriodicalId":50967,"journal":{"name":"American Journal of Dermatopathology","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144683557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Utility of Immunohistochemistry in Diagnosis of Papillary Eccrine Adenoma/Tubular Apocrine Adenoma (PEA/TAA).","authors":"Amanda J Nguyen, Ruifeng Ray Guo, Margot S Peters","doi":"10.1097/DAD.0000000000003069","DOIUrl":"https://doi.org/10.1097/DAD.0000000000003069","url":null,"abstract":"<p><strong>Abstract: </strong>Papillary eccrine adenoma/tubular apocrine adenoma (PEA/TAA) is a rare sweat gland neoplasm. Because PEA/TAA shares morphologic features with other sweat gland tumors, including digital papillary adenocarcinoma, histologic diagnosis may be challenging. We report a case of PEA/TAA presenting as a nodule on the left foot of a 43-year-old man. Histopathologic examination revealed a well-circumscribed dermal proliferation of variably sized glands composed of ductal cells with an outer layer of myoepithelial cells. By immunohistochemistry, the ductal tumor cells showed strong, diffuse expression of BRAF V600E, and the myoepithelial cells were positive for p63. This case illustrates the utility of immunohistochemistry in the diagnosis of this rare neoplasm. Particularly when PEA/TAA is located on an acral site, distinction from digital papillary adenocarcinoma is critical, because these tumors show significant differences in clinical behavior.</p>","PeriodicalId":50967,"journal":{"name":"American Journal of Dermatopathology","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144661002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ceren Unal, Sebile Guler Cekic, Zuhal Gucin, Serdar Aydin
{"title":"Giant Vulvar Pseudoangiomatous Stromal Hyperplasia After Bilateral Breast and Axillary Lesions: A Delayed Multifocal Presentation.","authors":"Ceren Unal, Sebile Guler Cekic, Zuhal Gucin, Serdar Aydin","doi":"10.1097/DAD.0000000000003066","DOIUrl":"https://doi.org/10.1097/DAD.0000000000003066","url":null,"abstract":"<p><strong>Abstract: </strong>Pseudoangiomatous stromal hyperplasia (PASH) is a benign myofibroblastic proliferation frequently encountered in the breast but rarely affects anogenital mammary-like glands, where it typically presents as small nodules. We report a rare case of a 38-year-old woman who developed a 95 × 60 × 60-mm vulvar mass 4 months after undergoing bilateral mastectomy and axillary excisions for histologically confirmed PASH. Pelvic MRI revealed a well-circumscribed, hypointense lesion in the posterolateral vaginal wall. Wide local excision was performed. Histopathology demonstrated a dense collagenous stroma with bland spindle cells forming interanastomosing slit-like, endothelial-free pseudovascular spaces, confirming the diagnosis of PASH. No fibroadenomatous component was observed. Immunohistochemical staining was positive for SMA and negative for CD31 and Factor VIII in the pseudovascular spaces, aiding in the exclusion of vascular neoplasms such as angiosarcoma. The patient remains recurrence-free at 1 year. This case highlights the potential for delayed multifocal PASH involving hormonally responsive anogenital sites, emphasizes its inclusion in the differential diagnosis of large vulvar masses, and underscores the need for surveillance of ectopic mammary-like tissues in patients with a history of PASH.</p>","PeriodicalId":50967,"journal":{"name":"American Journal of Dermatopathology","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144644098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Retrospective Analysis of the Utility of Polymerase Chain Reaction-Reverse Sequence-Specific Oligonucleotide (GENOSEARCH HPV31) and Human Papillomavirus Immunohistochemistry (BSB-66) in the Diagnosis of Digital Papillary Adenocarcinoma.","authors":"Tsubasa Hiraki, Toshihiro Takai, Yoshifumi Iwahashi, Shin-Ichi Murata, Yuna Noda, Masatoshi Jinnin, Shusuke Yoshikawa, Keisuke Goto","doi":"10.1097/DAD.0000000000003065","DOIUrl":"https://doi.org/10.1097/DAD.0000000000003065","url":null,"abstract":"<p><strong>Abstract: </strong>Digital papillary adenocarcinoma (DPA) is a rare malignant sweat gland tumor associated with human papillomavirus genotype 42 (HPV42). Currently, the only established test for detecting HPV42 in DPA is RNAscope in situ hybridization. However, this test incurs extremely high acquisition and running costs. To find an alternative method for the detection of human papillomavirus (HPV) in DPA, we evaluated the utility of polymerase chain reaction-reverse sequence-specific oligonucleotide (PCR-rSSO) (GENOSEARCH HPV31) and immunohistochemistry (IHC) using an anti-HPV antibody (BSB-66) for the detection of HPV in DPA. A total of 6 cases of DPA and 16 cases of other cutaneous tumors were reviewed, all of which had been practically performed by GENOSEARCH HPV31 using formalin-fixed paraffin-embedded (FFPE) tissues. The results revealed the presence of HPV42 in all 5 available cases of DPA (5/5, 100%) in GENOSEARCH HPV31. However, 1 case of DPA could not be processed because of poor DNA quality. HPV42 was not detected in the remaining 16 controls. IHC for HPV (BSB-66) showed no reactivity in any of the 6 DPA tumors. For the detection of HPV42 in the FFPE tissue of DPA, GENOSEARCH HPV31 can be used as an alternative to RNAscope in situ hybridization, unless the DNA quality in the FFPE tissue is poor. A notable advantage of GENOSEARCH HPV31 is its lower financial burden, both regarding purchase and operational costs, compared with RNAscope. Furthermore, GENOSEARCH HPV31 can identify additional 30 major genotypes of HPV, other than HPV42. By contrast, HPV (BSB-66) IHC cannot be used to detect HPV in DPA.</p>","PeriodicalId":50967,"journal":{"name":"American Journal of Dermatopathology","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144627686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Histiocytoid Variant of Cutaneous Apocrine Carcinoma: A Rare Case With Literature Review.","authors":"J N Aparnna, Biswanath Behera, Naveen Purushothaman, Madhusmita Sethy, Deepak Kumar Sahu, Pavithra Ayyanar","doi":"10.1097/DAD.0000000000003061","DOIUrl":"https://doi.org/10.1097/DAD.0000000000003061","url":null,"abstract":"","PeriodicalId":50967,"journal":{"name":"American Journal of Dermatopathology","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144610185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Architecturally Low-Grade Pure Cylindrocarcinoma With CYLD1 Mutation.","authors":"Ronan Knittel, Shona Hendry, Benjamin A Wood","doi":"10.1097/DAD.0000000000002984","DOIUrl":"https://doi.org/10.1097/DAD.0000000000002984","url":null,"abstract":"<p><strong>Abstract: </strong>Cylindrocarcinoma is a very rare malignant adnexal neoplasm. The diagnosis of cylindrocarcinoma typically requires identifying a precursor benign component; indeed the current World Health Organization classification classifies these lesions within the group of malignant neoplasms arising from cylindroma. We present a unique case of architecturally low-grade pure cylindrocarcinoma, supported by striking morphologic and immunohistochemical features and showing an inactivating CYLD1 mutation.</p>","PeriodicalId":50967,"journal":{"name":"American Journal of Dermatopathology","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144592801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Katharina Janda, Sena Zengin, Nicholas Zoumberos, Sara Shalin
{"title":"Merkel Cell Carcinoma Arising in Combination With Basal Cell Carcinoma: A Rare Diagnosis and Potential Pitfall.","authors":"Katharina Janda, Sena Zengin, Nicholas Zoumberos, Sara Shalin","doi":"10.1097/DAD.0000000000003052","DOIUrl":"https://doi.org/10.1097/DAD.0000000000003052","url":null,"abstract":"<p><strong>Abstract: </strong>Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine skin cancer, often associated with a poor prognosis due to its propensity for rapid growth, local recurrence, and metastasis. Combined squamous and Merkel cell carcinoma are welldescribed in the literature; however, concomitant basal cell and Merkel cell carcinoma are exceedingly uncommon. We report a 69-year-old male patient presenting with red, crusted, exophytic plaque on the right postauricular area. Further evaluation revealed nodular basal cell carcinoma (BCC) with an additional, morphologically, and immunophenotypically distinct neuroendocrine component, and areas indicating possible lymphovascular invasion. Overall, the histopathology was most compatible with a combined tumor involving Merkel cell carcinoma and basal cell carcinoma. Our case suggests that this unusual morphologic appearance of Merkel cell carcinoma can be overlooked and should be recognized when evaluating biopsies demonstrating basal cell carcinoma.</p>","PeriodicalId":50967,"journal":{"name":"American Journal of Dermatopathology","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144555646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Facial HPV6-Positive in Situ Squamous Cell Carcinoma With Small Cell Features Mimicking Merkel Cell Carcinoma.","authors":"Sonsoles Berenguer-Ruiz, Carmen-Amalia Vásquez-Dongo, Noelia Perez-Muñoz, Maria-Teresa Fernández-Figueras","doi":"10.1097/DAD.0000000000003064","DOIUrl":"https://doi.org/10.1097/DAD.0000000000003064","url":null,"abstract":"<p><strong>Abstract: </strong>We describe a previously unreported variant of cutaneous squamous cell carcinoma in situ (SCCis) with small cell morphology mimicking intraepidermal Merkel cell carcinoma. The lesion, arising on the upper lip of an 86-year-old man, displayed biphasic histology: a predominant population of small basaloid cells and a superficial bowenoid component. Immunohistochemistry showed divergent expression patterns, and PCR confirmed HPV6. Complete spontaneous regression occurred post-biopsy. This case expands the histopathologic spectrum of SCCis and suggests an intraepidermal basaloid variant potentially linked to low-risk alpha HPV.</p>","PeriodicalId":50967,"journal":{"name":"American Journal of Dermatopathology","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144561899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lina Al-Soufi, Aya Marashli, Mohammad Adi, Yaman Saiouf, Zuheir Al-Shehabi
{"title":"Zosteriform Mycosis Fungoides: A Case Report and Literature Review.","authors":"Lina Al-Soufi, Aya Marashli, Mohammad Adi, Yaman Saiouf, Zuheir Al-Shehabi","doi":"10.1097/DAD.0000000000003057","DOIUrl":"https://doi.org/10.1097/DAD.0000000000003057","url":null,"abstract":"<p><strong>Abstract: </strong>Primary cutaneous lymphomas are the third most common lymphomas, with mycosis fungoides (MF) being the predominant subtype of cutaneous T-cell lymphoma. Zosteriform distribution of MF is a rare presentation, complicating diagnosis and management because of its resemblance to other skin disorders. This subtype usually presents with typical lesions of classic MF, including patches and patches that progress to plaques and sometimes tumors, but in a distribution limited to a dermatomal distribution. This case involves a 29-year-old woman with a recurrent, unilateral itchy, and painful rash on her lower back, misdiagnosed for a decade as fungal infection and eczema. The rash evolved into a resistant scaly plaque, unresponsive to steroids and phototherapy. Histopathologic examination of skin biopsies suggested large plaque parapsoriasis. Based on clinical, histologic, and therapeutic response features, a final diagnosis of early-stage MF was established. The patient showed partial improvement after treatment with methotrexate and corticosteroids. Zosteriform MF is a rare and challenging variant, showing relatively good prognosis in most cases. Literature review highlights its occurrence across a wide age range, with prior herpes zoster viral infection proposed as a potential trigger influencing disease onset and distribution. Treatment outcomes vary, with some patients benefiting from immunosuppressive therapies, while others experience recurrence or poor prognosis. Zosteriform MF is a rare, diagnostically challenging variant of MF. This case underscores the importance of thorough diagnostic evaluation and the potential for variable treatment responses. Further research is needed to understand its pathogenesis and optimize therapeutic strategies.</p>","PeriodicalId":50967,"journal":{"name":"American Journal of Dermatopathology","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144561900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Demodex Infestation in Discoid Lupus Erythematosus: A Histopathologic Study.","authors":"Gülhan Aksoy Saraç, Selma Emre, Merve Kaya, Rümeysa Kankoç, Gülnaz Kurt Çevik, Nuran Süngü","doi":"10.1097/DAD.0000000000003058","DOIUrl":"https://doi.org/10.1097/DAD.0000000000003058","url":null,"abstract":"<p><strong>Abstract: </strong>Discoid lupus erythematosus (DLE) is a chronic form of cutaneous lupus that mainly affects the face, scalp, and neck. It presents as erythematous and infiltrated plaques that may lead to atrophy, scarring, and alopecia. Recent studies suggest a possible link between Demodex mite infestation and DLE pathogenesis. This study aims to evaluate the prevalence of Demodex mites in patients with DLE and their potential role in disease pathogenesis. A total of 85 histopathologically and clinically confirmed patients with DLE were assessed. Clinical and histopathologic data were collected, and hematoxylin-eosin-stained biopsy specimens were evaluated for Demodex infestation. Demodex mites were detected in 31 patients (36.5%). Infestation was more common in face localization (47.1%) than in scalp (16.7%) (P = 0.006). No significant association was found between Demodex positivity and age, sex, or histopathologic findings of DLE. Although Demodex mites may not play a direct role in DLE pathogenesis, their increased prevalence in facial lesions suggests a secondary association because of immune dysregulation and autoimmune background. Further studies are needed to assess the impact of Demodex positivity on DLE progression, pathogenesis, and treatment response.</p>","PeriodicalId":50967,"journal":{"name":"American Journal of Dermatopathology","volume":" ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144561898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}