American Journal of Dermatopathology最新文献

Abstract: PCR-based fragment analysis of the T-cell receptor (TCR) gene is used extensively in diagnostic labs to assess clonality in T-cell populations in multiple tissue sites. Of the numerous TCR assays that have been reported, studies assessing use on biopsies suspicious for mycosis fungoides specifically are lacking. We compared clonality findings from a previously run 2-tube/2-fluorochrome dye assay to a redesigned 1-tube/1-fluorochrome dye assay on formalin-fixed skin biopsies. Overall, the accuracy of the 2-tube assay was marginally better (75.7% vs. 71.4%), when using clinical history combined with histologic diagnosis as the gold standard. The 2-tube assay had better sensitivity (73.7% vs. 65.8%), while the 1-tube assay had superior specificity (93.8% vs. 87.5%). Clonality results were easier to interpret with the 1-tube assay. In nearly 19% of cases, a change of assays on the same biopsy resulted in a change of clonality interpretation. For laboratories that change TCR-γ clonality assays, follow-up biopsies for mycosis fungoides assessment may result in a change of diagnosis.

Abstract: Cutaneous malignant squamomelanocytic tumor (SMT) is a rare neoplasm comprising 2 distinct cell populations of squamous cell carcinoma and a second component of either benign or malignant melanocytes. SMT most often presents as a keratotic papule in areas of chronic sun exposure, typically on the head or neck of middle-aged and elderly-aged, White male patient populations. In recent years, there has been an increase in case reports, including a review article published in 2023, identifying a total of 37 cases published in the literature. There are only 3 reported cases in the literature with spindled or dendritic cells in the melanocytic component, as most have been of the epithelioid subtype. Despite the increasing prevalence, the origin and pathophysiology is poorly understood. We report 2 cases of SMT with dendritic melanocytes that are centered around a hair follicle, proposing the theory that these 2 distinct cell types may arise from the hair follicles.

Abstract: Pseudolymphomatous cutaneous angiosarcoma (cAS) is a rare subtype characterized by a prominent lymphocytic infiltrate, posing diagnostic challenges due to its resemblance to lymphoid neoplastic processes. We present a novel case highlighting the clinical and histopathological features, notably its association with persistent firm facial edema in a patient with systemic sclerosis (SSc). A 47-year-old woman with a 21-year history of SSc presented with firm palpebral edema evolving to involve the entire face and cervical region over six months. Diagnostic imaging revealed inflammatory changes in orbital regions, supradiaphragmatic lymphadenopathies, and lytic lesions. Skin biopsy demonstrated a diffuse neoplasm with vascular channels and solid areas, accompanied by dense lymphocytic proliferation. Pseudolymphomatous cutaneous angiosarcoma, a rare malignant neoplasm, exhibits variable clinical presentations and rapid progression. Histologically, it manifests as irregularly shaped vascular channels lined by prominent endothelial cells. Immunohistochemistry, particularly markers such as v-ets erythroblastosis virus E26 oncogene homolog (avian) (ERG), aids in diagnosis. Notably, this case marks the first presentation of cAS with persistent facial edema in SSc, highlighting the association between SSc and cancer risk. This case underscores the diagnostic challenges posed by cAS and emphasizes the importance of early detection for optimal patient outcomes. Further understanding of its association with autoimmune disorders such as SSc is crucial for comprehensive management strategies.

Abstract: Cutaneous sarcomatoid squamous cell carcinoma is well-described with histology resembling pleomorphic undifferentiated sarcoma featuring collagenous or myxoid stroma with or without elements of keratinizing squamous carcinoma. This report presents 2 cases of dedifferentiated squamous cell carcinoma (SCC) composed of sheets of malignant mononuclear cells with malignant osteoclast-like multinucleated giant cells, extravasated blood, and hemosiderin resembling cutaneous giant cell tumor (cGCT). In the first case, an exophytic facial mass of a 96-year-old woman removed by shave showing extensive cGCT-like tumor but with microscopic elements of SCC in situ and positivity for cytokeratin 5/6 in the malignant spindle cells and SCC. The second case involved a 32-year-old man with a pedunculated penile mass removed by shave biopsy, displaying malignant cytology resembling cGCT, focal staining for cytokeratin AE1/AE3 and p63, and CD68 highlighting the osteoclast-like giant cells. Molecular analysis revealed CDKN2A, TP53, and TERT. Upon reexcision, case 2 showed focally invasive keratinizing SCC associated with differentiated penile intraepithelial neoplasia and lichen sclerosus. Skin specimens with an exophytic mass histologically resembling cGCT but with malignant cytology should be meticulously evaluated for elements of SCC. Molecular analysis, detecting mutations like H3F3 or HMGA2-NCOR2 fusion, can aid in distinguishing cutaneous sarcomatoid squamous cell carcinoma from GCT bone or GCT soft tissue.

Abstract: Refractory celiac disease (RCD) is a rare condition characterized by persistent malabsorptive symptoms and villous atrophy despite a gluten-free diet. While RCD type 1 has a normal intraepithelial lymphocyte phenotype, RCD type 2 is defined by the presence of immunophenotypically aberrant and monoclonal intraepithelial T lymphocytes, with a high propensity to transform to enteropathy-associated T-cell lymphoma (EATL). Although dermatological manifestations of celiac disease are common, presentation with cutaneous involvement by abnormal lymphocytes of RCD type 2 or EATL is rare, with few histologic descriptions in the literature. We describe the case of a 66-year-old man with a history of celiac disease presenting with a generalized, erythematous papular rash over his torso, upper arms, and legs. Biopsy of his skin lesions showed prominent hyperkeratosis with underlying spongiosis and interface change. Increased intraepithelial (epidermotropic) lymphocytes were observed, out of proportion to the level of spongiosis, but not overly atypical in appearance. Immunohistochemistry revealed an aberrant T-cell immunophenotype (CD3/2/7 positive; CD5/4/8 negative), raising suspicion for a cutaneous T-cell lymphoproliferative disorder. A duodenal biopsy demonstrated total villous atrophy with a morphologically bland population of epitheliotropic T lymphocytes showing the same aberrant immunophenotype. Similar cells were also identified by flow cytometry in the peripheral blood. In conjunction with the history of celiac disease, a diagnosis of RCD type 2 or 'EATL in situ' with cutaneous involvement was made. Cutaneous RCD type 2 or EATL should be considered as differential diagnoses in patients with a history of celiac disease and histopathology reminiscent of epidermotropic forms of cutaneous T-cell lymphoma.

Abstract: Abnormalities in the expression of cytokeratins or adhesion molecules have been associated with hair disorders. The expression patterns of these molecules in the hair follicles of developing human fetuses are not obvious. We aimed to investigate the expression patterns of some cytokeratins and adhesion molecules in the hair follicle of human fetuses and compared them with adults. Forty-eight fetuses of >16 gestational weeks and 22 adult cases with total excisions of benign nevi or cysts were enrolled. The skin samples were taken from both the scalp and back of the fetuses. The histopathologically normal skin areas were evaluated in adults. CK19, CK20, CAM5.2, high-molecular-weight cytokeratin, E-cadherin, β-catenin, and CD56 immunohistochemical stainings were performed. In the fetus group, the staining scores declined in the third trimester but elevated and reached the highest level in adults, except for CD56, which did not stain any adult samples. All stainings were mostly observed in the outer root sheath, except CD56 that stained the perifollicular dermal sheath only in fetuses. E-cadherin, β-catenin, and high-molecular-weight cytokeratin strongly and diffusely stained all adult samples. CAM5.2 and CK19 scores were correlated in fetuses (scalp scores: r s = 0.405, P = 0.004; back scores: r s = 0.422, P = 0.003) and adults (back scores: r s = 0.562, P = 0.046). CD56 negativity indicated the immune-privilege feature of adult hair follicles. As CK19, CAM5.2 may be used to find the regions of stem cells or transient amplifying cells.

Abstract: Cutaneous perivascular hemophagocytosis (CH) is a histological manifestation that manifests as systemic hemophagocytic syndrome, also known as hemophagocytic lymphohistiocytosis, when accompanied by fever, hepatosplenomegaly, liver dysfunction, and cytopenia, and may rarely manifest independently of hemophagocytic lymphohistiocytosis. CH typically presents as purpuric or brownish macules and patches on the extremities, abdomen, and trunks. Histopathologically, the hallmark of CH includes extravasated erythrocytes and karyorrhectic debris phagocytized by histiocytes, associated with dermal capillary ectasia, perivascular infiltration of neutrophils, nuclear dust, and histiocytes without atypia. In this study, we report 2 cases of CH encountered in routine diagnostic practice and elucidate their significant clinical and histologic features. Our first patient had leukocytoclastic vasculitis with CH in the setting of Yersinia enterocolitis, and the second case represents CH in association with non-Hodgkin lymphoma. This study highlights the importance of considering CH as a potential indicator of underlying systemic pathology, including infectious and hematological disorders, in clinical practice.

Abstract: In 4%-11% of cases, melanoma recurrences present as in-transit (IT) metastases, and their prognosis is quite poor. Consequently, an early diagnosis and treatment of IT metastasis assume paramount significance. Despite this, the diagnosis of cutaneous IT metastases persistently presents a formidable challenge due to the diversity in clinical and dermoscopic characteristics. We provide a novel melanoma IT metastases pattern with interesting dermoscopic features and magnetic resonance imaging via presenting an unusual case characterized by diffuse subcutaneous intravascular lesions to supplement the understanding of cutaneous melanoma IT metastases.

Background: Following transition to digital pathology for primary diagnosis at our institution, dermatology residents have reduced exposure to light microscopy. This study compares resident competency with light microscopy versus digital pathology following practice changes.

Methods: Twenty-one dermatology residents were administered a dermatopathology examination composed of 32 diagnoses evaluated using digital slides and 32 with light microscopy. Case difficulty was graded and balanced between modalities. Diagnostic accuracy was measured using the number of correct diagnoses for each modality. Participants were surveyed regarding their experience and preferences.

Results: Diagnostic accuracy was higher with digital pathology than light microscopy (22/32 vs. 18/32, P < 0.001). Diagnostic accuracy with digital pathology increased with years of training, but accuracy with light microscopy did not. Residents with previous light microscopy experience achieved an average score of 19/32 on glass, as compared with 10/32 for those without experience (P = 0.039). Digital pathology was preferred over light microscopy (18/21, 85.7%).

Conclusions: Trainees had better diagnostic proficiency with digital pathology and preferred this modality. Most practices at this time continue to use light microscopy. Therefore, we need to maintain proficiency in microscopy during training while concurrently preparing trainees for a digital future.