American Journal of Dermatopathology最新文献

Abstract: Symplastic glomus tumors are a rare subtype of glomus tumor defined by nuclear atypia without additional markers of malignancy such as large size, deep location, or atypical/prevalent mitotic figures. Glomus tumors, including the symplastic subtype, most commonly present in the subungual area with rarer extradigital presentation. To our knowledge, there have been less than 25 cases of symplastic glomus tumors described in the literature. Herein, we present a case of extradigital symplastic glomus tumor with review of the literature.

Background: Maculopapular cutaneous mastocytosis (MPCM) is a rare disorder characterized by a pathologic accumulation of mast cells in the skin, which may or may not be accompanied by systemic mastocytosis. Diagnosis of MPCM on skin biopsy can be challenging because the findings may be subtle. Although mast cell density in MPCM has been reported, data informing a proposed cutoff for diagnosis and diagnostic criteria are limited.

Methods: We identified adult patients diagnosed with MPCM and urticarial tissue reaction/chronic urticaria on skin biopsy and compared the mast cell and eosinophil counts per 1 mm2 in 10 cases each of MPCM, chronic urticaria, and normal skin from routine biopsies. All slides were stained with CD117, and CD117-positive mast cells were counted per 1 mm2 using digital microscopy. Eosinophils were counted on hematoxylin and eosin-stained slides per 1 mm2 using digital microscopy.

Results: The median number of mast cells per 1 mm2 was significantly higher in MPCM than in cases of urticaria and normal skin/control tissue (177.3 vs. 26.8 vs. 47.8 mast cell per mm2, respectively; P ≤ 0.001). The calculated "cut point" for mastocytosis versus chronic urticaria and normal skin was 66 mast cells per 1 mm2, whereas the value for controls versus urticaria was 37 mast cells per 1 mm2. Eosinophils had similar density in MPCM and urticaria, and their presence was significant in the differentiation of MPCM and urticaria from normal tissue.

Conclusions: This study adds to the literature by providing objective mast cell density data to distinguish challenging cases of cutaneous mastocytosis from urticarial reactions and normal skin. Future studies could explore the development of computer-aided estimations of cellular density with more extensive comparison with other inflammatory conditions to translate our findings more readily into clinical practice.

Introduction: Leprosy is a neglected infectious disease caused by Mycobacterium leprae and Mycobacterium lepromatosis and remains a public health challenge in tropical regions. Therefore, the development of technological tools such as machine learning (ML) offers an opportunity to innovate strategies for improving the diagnosis of this complex disease.

Objective: To validate the utility of different ML models for the histopathological diagnosis of Hansen disease.

Methodology: An observational study was conducted where 55 H&E-stained tissue slides from leprosy patients and 51 healthy skin controls were analyzed using microphotographs captured at various magnifications. These images were categorized based on histopathological findings and processed using the Cross-Industry Standard Process for Data Mining methodology for designing and training ML models. Five types of ML models were evaluated using standard metrics such as accuracy, sensitivity, and specificity, emphasizing data normalization as a fundamental step in optimizing model performance.

Results: The artificial neural network (ANN) model demonstrated an accuracy of 70%, sensitivity of 74%, and specificity of 65%, demonstrating its ability to identify leprosy cases with moderate precision. The receiver operating characteristic curve of the ANN model showed an area under the curve of 0.71. Conversely, models such as decision trees, logistic regression, and random forests showed similar accuracy results but with slightly lower sensitivity, potentially indicating a higher risk of false negatives in detecting leprosy-positive cases.

Conclusion: The ANN model emerges as a promising alternative for leprosy detection. However, further refinement of these models is necessary to enhance their adaptability across different clinical settings and participation in patient care.

Abstract: Histiocytoses constitute a group of heterogeneous disorders characterized by involvement of variable organs by neoplastic macrophage or dendritic cells. They may affect both adults and children with a predilection to the skin, bone, lungs, lymph nodes, and CNS. The coexistence of different types of histiocytoses in the same patient is an extremely rare phenomenon. We describe a very rare case of co-occurring pulmonary Langerhans cell histiocytosis with multiple cutaneous reticulohistiocytomas with a common BRAF-V600E mutation as the driver genetic event in both the lung and skin lesions. The presence of a common BRAF-V600E mutation provides evidence of their clonal relation and contributes to our understanding in the pathogenesis of multiple, co-occurring histiocytic proliferations.

Abstract: Myositis ossificans is a benign ossifying nodule that can affect any type of tissue but is most commonly found in muscle. Occurrence in the soft tissue of the subcutis is less common and has been referred to as panniculitis ossificans. In this case report, we describe a 46-year-old woman who presented with a 1.7 × 2.0 cm lesion on the abdomen that had been present for several months, was painful, and easily irritated by clothing. Initial clinical assessment based on history and physical examination was an epidermal cyst and removal by excision was performed. Initial histologic findings showed a spindle cell proliferation in the subcutis along with bone formation. Osteoblasts were noted to be rimming the bone and giant cells were present. The spindle cells were SMA positive and partially factor XIIIa positive while S100 protein staining was negative, confirming the diagnosis of panniculitis ossificans.

Abstract: Nail involvement is seen in 10% of lichen planus patients, with a subset developing severe destruction of the nail matrix. Nail biopsy is a complex procedure usually done when nails are the only site of involvement. The pathology of nail lichen planus (NLP) has been the subject of very few studies. Most studies refer to the major and minor histopathologic criteria proposed by Hanno et al. This study aims to characterize the histopathologic features of NLP. Twenty five patients of NLP with nail biopsies, diagnosed in the last 10 years were included in the study. Lichen planus was suspected in all patients, and the alternative diagnosis was psoriasis/onychomycosis and melanoma. On histopathology, the common features included acanthosis (88%), lichenoid lymphocytic inflammation (96%), and hypergranulosis (72%). Detachment of epithelium from the subepithelium, a hitherto unreported feature, was noted in 60% of cases. Less common features were lymphocytic exocytosis (48%), melanophages (40%), basal vacuolar alteration (24%), apoptotic keratinocytes (28%), fraying of the nail plate (24%), and spongiosis (20%). Understanding the common and less common histopathologic features and their correlation with clinical findings is essential to diagnose NLP accurately rather than stressing histologic criteria as major/minor, which may lead to the underdiagnosis of cases.

Abstract: The fibroadipose vascular anomaly (FAVA) is a relatively unknown vascular anomaly in the realm of adult dermatopathology. Despite its intramuscular location, dermatologists often encounter cases, approaching them surgically under the presumption of a potential lipoma. This entity was first described in 2014, and consequently, many FAVA cases may be concealed in our archives under diagnoses of other entities that require differential diagnoses, such as intramuscular fast-flow vascular anomaly. Clinically, these anomalies typically manifest preferably in young women or girls and predominantly in the extremities. In this article, we present 2 cases of FAVA with atypical clinical features in terms of their topography and age at onset. However, histopathologically, they exhibit typical characteristics with fibroadipose tissue and dysmorphic venous vessels dissecting the affected striated muscle.

Abstract: Mpox, previously referred to as monkeypox, was recently deemed a public health emergency in 2022. Our understanding of potential secondary cutaneous manifestations in the setting of this infection is still evolving. We report a rare case of a man who presented with erythematous, painful subcutaneous nodules on his extremities in the setting of recent mpox infection. Biopsy of a lesion from the lower legs revealed a lobular panniculitis with lupus panniculitis-like features on pathology. He was ultimately diagnosed with a unique case of reactive panniculitis secondary to mpox.

Abstract: Chronic graft-versus-host disease (cGVHD) is the leading cause of morbidity and nonrelapse mortality after allogeneic hematopoietic cell transplantation. Skin biopsy of cGVHD is recommended when clinical features are not diagnostic, yet the histopathologic features of skin cGVHD are not well described. The objective of this study is to describe the histopathologic features of skin cGVHD in epidermal, sclerotic, and combination cGVHD. Of 49 patients with skin cGVHD, 30 of 49 (61.2%) were male, and mean age was 55 years (SD 11.1). Clinically, 33 of 49 (67.3%) had epidermal cGVHD (E-cGVHD), 1 of 49 (2.1%) had sclerotic cGVHD (S-cGVHD), and 15 of 49 (30.6%) had combination disease. The 49 patients corresponded to 83 unique pathologic specimens with 67 of 83 (80.7%) taken from E-cGVHD, and 16 of 83 (19.3%) from S-cGVHD lesions. Nearly all biopsy specimens from E-cGVHD showed minimal features of active GVHD, including apoptosis in the epidermal basal layer (n = 63, 94.0%), vacuolar change (n = 62, 92.5%), and lymphocyte satellitosis (n = 57, 85.1%). The predominant histologic pattern of E-cGVHD was lichen planus/interface dermatitis (n = 31, 47.0%). S-cGVHD specimens also showed minimal features of active GVHD with apoptosis of the epidermal basal layer (n = 11, 68.8%) and vacuolar change (n = 8, 50.0%). In addition, S-cGVHD showed sclerosis of the papillary and reticular dermis and subcutaneous septae (n = 8, 50.0%; n = 11, 68.8%; n = 5, 31.2%, respectively). The predominant histologic pattern of S-cGVHD was lichen sclerosus/morphea-like pattern (n = 10, 62.5%). Although minimal pathologic features of active GVHD are common, the majority of cGVHD biopsies share features with the inflammatory skin diseases that they clinically resemble. Complete histologic reporting is recommended with implications for disease endotyping and personalized therapy.