American Journal of Dermatopathology最新文献

Abstract: Bullous lupus erythematosus (BLE) and linear IgA disease (LAD) are rare autoimmune subepidermal blistering diseases, with overlapping features despite different pathogenetic mechanisms. Diagnosis is based on immunofluorescence and serology. This retrospective study was undertaken to compare the histopathologic features of BLE and LAD (11 cases each). The mean age was 36 years in both groups, and female preponderance was noted in BLE. Clinically, all cases presented as tense, itchy blisters distributed over the trunk, face, and extremities. Subepidermal neutrophil-rich blisters were seen in 60% BLE and 54.54% LAD cases. Eosinophils in the blisters were noted in 4 cases (36.4%) of linear IgA bullous dermatosis, but not in any of the BLE cases. The adjacent epidermal changes noted include spongiosis (33%; 40%), papillary microabscesses (22%; 20%), and basal tagging by neutrophils (77%; 70%). Superficial perivascular inflammation was seen in all cases while deep perivascular inflammation was observed in 54% BLE and 36% LAD cases. Lymphocytes were the predominant infiltrate. Increased dermal mucin was seen in 60% BLE and 45% LAD cases. None of the histopathologic features showed a statistically significant difference between the 2 groups. Hence, histopathology alone is of limited value in distinguishing the 2 groups. Diagnosis rests on immunofluorescence and serologic findings, which should be used even in cases that seem to be classic LAD or patients without history of systemic lupus erythematosus.

Abstract: Hepatocellular carcinoma (HCC) rarely metastasizes to the skin. When it occurs, it is often poorly differentiated making the diagnosis challenging. There exists a male predominance, and clinical presentation usually includes papules or nodules resembling pyogenic granulomas or dermal deposits. Histopathology shows malignant dermal cells. Hepatoid features including nests or cords of cells arranged in a trabecular or pseudoglandular pattern, sinusoidal formation, or the presence of bile exist in less than 50% of cases. Limitations exist with immunohistochemical staining, particularly in poorly differentiated neoplasms. Albumin in situ hybridization is more sensitive for detecting poorly differentiated HCC. Immunostaining in conjugation with albumin in situ hybridization enhances the detection of metastatic hepatocellular carcinoma. We report the case of a 74-year-old man with a history of HCC and a stable lung metastasis who presented with painful, growing bumps on his nose for 2 months. Examination revealed multiple, pink to white, shiny dermal-based papules with telangiectasias involving the right nasal tip and naris. Alpha-fetoprotein level was markedly elevated. Computed tomography showed expanding right lower lobe lung nodules. Histopathology of the cutaneous biopsy revealed features of a poorly differentiated basaloid carcinoma. Immunohistochemical staining was diffusely positive for glypican-3, focally positive for arginase-1, and negative for hepatocyte paraffin 1. Albumin in situ hybridization was diffusely positive, clinching the diagnosis of HCC. Metastatic HCC is a rare encounter for dermatopathologists. We aim to increase awareness of its occurrence in patients with advanced HCC and highlight the importance of clinical correlation when faced with poorly differentiated or unusual-looking basaloid neoplasms.

Abstract: Mesothelioma of the tunica vaginalis testis (MMTVT) is a rare neoplasm comprising <3% of all cases of malignant mesothelioma (MM). MMTVT derives from the tunica vaginalis testis, an outpouching of the mesothelial-lined abdominal peritoneum that detaches from the abdominal cavity after the descent of the testis. Similar to pleural mesothelioma, asbestos exposure is a known risk factor. However, MMTVT has a better prognosis than pleural mesothelioma. Cutaneous metastases from MMTVT are exceedingly rare. Herein, we describe a case of a 67-year-old man with a history of asbestos exposure presenting with scrotal pain and indurated plaques on his lower abdomen and scrotum. Histologic sections showed a sheet-like dermal proliferation comprising epithelioid cells with necrosis and increased mitotic activity. The clinical and histologic differential diagnosis was broad, including metastatic carcinoma, melanoma, sarcoma, germ cell tumor, hematologic malignancy, neuroendocrine carcinoma, and malignant mesothelioma. By immunohistochemistry, the neoplastic cells were positive for WT1, D2-40, and AE1/AE3, with rare positivity for calretinin, consistent with a diagnosis of mesothelioma. Additional immunohistochemical studies provided no support for the other diagnostic considerations listed above. BAP1 showed retained nuclear expression (normal) by immunohistochemistry. A DNA sequencing panel identified copy number losses in CDKN2A, MTAP, CDKN2B, and NF2, which are frequently identified genetic alterations in malignant mesothelioma. Subsequent testicular imaging demonstrated a diffusely thickened scrotal wall with an enlarged left testicle. Overall, this represents a case of malignant mesothelioma presenting with cutaneous metastases to the scrotum and lower abdomen, with clinical and imaging features suggestive of primary MMTVT. The International Mesothelioma Interest Group recommends using at least 2 mesothelial markers, such as calretinin, WT1, CK5/6 or D2-40, and 2 epithelial markers, such as claudin-4, CEA, MOC-31, as well as a broad-spectrum cytokeratin stain (AE1/AE3) as part of an initial immunohistochemical panel. Metastatic mesothelioma should be included in the differential diagnosis of malignant epithelioid dermal tumors with unusual staining patterns.

Abstract: Superficial papular neuroma is a rare cutaneous spindle cell lesion, with only 5 cases reported in 2 studies. We document 2 additional cases in a 45-year-old man and a 43-year-old woman (the first case identified in a woman). Clinically, superficial papular neuromas appear as a single, non-specific papule on the head, neck, or back. Histologically, these lesions are within the papillary and superficial reticular dermis, with nerve-like structures composed of bland spindle-shaped cells intersecting normal tissue with mild reactive acanthosis. The cells are SOX10 positive with neurofilament protein staining multiple axons within. The nerve-like structures in this study were occasionally surrounded by a thin rim of CD34 positivity, with no epithelial membrane antigen staining, similar to normal sensory neurons. Superficial papular neuroma are rare benign neoplasms with no reports of recurrence, even when incompletely excised.

Abstract: Regression (total or partial) is a common phenomenon in melanoma. From a pathogenic perspective, it is highly complex and only partially understood, involving aspects of both the tumor and the individual. One of the determining factors is the clonal selection of the tumor, wherein some clones within the tumor survive while others perish. This clonal selection can sometimes occur as a selective mechanism after the initiation of a therapeutic intervention. In many of these cases, the effect is detrimental, because the surviving clone is resistant to the applied therapy. However, occasionally, the therapy can successfully select the less harmful clone. We present an example of the latter, where therapy with interferon induced regression of the metastatic-capable melanocytic population, with only the primary tumor melanocytic population persisting. To confirm this, we demonstrated BRAF mutational similarity between the 2 populations, and an additional NRAS mutation in the metastatic population, which was absent in the primary tumor.

Background: Focal acantholytic dyskeratosis (FAD) and epidermolytic hyperkeratosis (EHK) are common incidental epidermal histologic findings within dysplastic nevi biopsies. We evaluate whether areas of FAD and EHK within dysplastic nevi biopsies stain with immunostains used to characterize melanocytic neoplasms.

Methods: In this case series, a natural language search of histopathology reports from our institution in the past year (2020-2021) identified dysplastic nevus biopsies with concurrent FAD and/or EHK. Tissue samples were examined for positive melanocytic immunostaining with SOX-10 and Melan-A in areas of FAD and EHK.

Results: Out of 32 biopsies, 20 of 26 FAD specimens (76.9%) and 2 of 6 EHK specimens (33.3%) showed unexpected suprabasal layer staining with a melanocytic marker that did not correspond to definitively identified melanocytes on the H&E-stained sections. The immunohistochemical staining of FAD and EHK was observed in 2 forms: nonspecific background staining or "true" staining (ie, seemed nuclear on SOX-10 or cytoplasmic on Melan-A).

Conclusions: This pilot examination provides evidence that areas of incidental FAD within dysplastic nevi biopsies demonstrate unexpected suprabasal layer staining with melanocytic markers. When dermatopathologists evaluate melanocytic neoplasms with melanocytic markers, it is possible the presence of incidental FAD could lead to over diagnosing pagetoid scatter within these lesions. This study is a proof of concept with mild to moderately dysplastic nevi that do not typically incur the use of melanocytic stains; however, the implication of this unexpected staining pattern would be important when using melanocytic markers on borderline melanocytic neoplasms that have incidental FAD. Close correlation with H&E is imperative to prevent misinterpretation in these cases.

Abstract: Pulse granulomas are unusual foreign body reactions to exogenous plant material, featuring the presence of hyaline ring structures and granulomatous inflammation. Pulse granulomas have been reported to occur in the oral cavity, gastrointestinal tract, and respiratory tract. Cutaneous pulse granulomas are exceedingly rare. All reported cases have been closely associated with underlying pathology such as chronic inflammatory conditions, trauma, or surgical procedures which likely facilitated implantation of exogenous plant material. We report a novel case of a cutaneous pulse granuloma presenting in the perianal region of an otherwise healthy man. The authors propose that the source of the exogenous plant material is plant-derived baby wipes, which the patient had been using daily to the perianal region.

Background: Subcutaneous Sweet Syndrome (SSS) is a rare variant of Sweet Syndrome characterized by neutrophilic infiltration of subcutaneous adipose tissue without vasculitis. The presence of vasculitis in SSS is uncommon and poses diagnostic challenges.

Case presentation: A 38-year-old female presented with a one-year history of recurrent painful erythematous nodules on her limbs and face. Physical examination revealed asymmetrical erythematous patches and tender subcutaneous nodules with central necrotic eschars on the lower limbs. Laboratory tests were unremarkable except for a mildly elevated erythrocyte sedimentation rate. Histopathological analysis showed significant neutrophilic infiltration within the adipose lobules and vascular walls, along with extravasation of red blood cells, indicating vasculitis. The patient responded promptly to systemic corticosteroids; however, symptoms recurred upon tapering, necessitating ongoing steroid therapy.

Discussion: This case underscores the rare occurrence of vasculitis in SSS, expanding the histopathological spectrum of the disease. Literature review suggests that vasculitis in SSS may result from neutrophil-mediated vascular damage rather than immune complex deposition. The recurrent symptoms upon steroid tapering highlight the therapeutic challenges in managing SSS with vasculitis.

Conclusion: Recognition of vasculitis in SSS is crucial for accurate diagnosis and effective management. Further research is warranted to elucidate the pathogenesis and develop targeted treatment strategies for SSS with vasculitis.