Differentiation and risk stratification of basal cell carcinoma with deep learning on histopathologic images and measuring nuclei and tumor microenvironment features.

BACKGROUND: Nuclear pleomorphism and tumor microenvironment (TME) play a critical role in cancer development and progression. Identifying most predictive nuclei and TME features of basal cell carcinoma (BCC) may provide insights into which characteristics pathologists can use to distinguish and stratify this entity. OBJECTIVES: To develop an automated workflow based on nuclei and TME features from basaloid cell tumor regions to differentiate BCC from trichoepithelioma (TE) and stratify BCC into high-risk (HR) and low-risk (LR) subtypes, and to identify the nuclear and TME characteristics profile of different basaloid cell tumors. METHODS: The deep learning systems were trained on 161 H&E -stained sections which contained 51 sections of HR-BCC, 50 sections of LR-BCC and 60 sections of TE from one institution (D1), and externally and independently validated on D2 (46 sections) and D3 (76 sections), from 2015 to 2022. 60%, 20% and 20% of D1 data were randomly splitted for training, validation and testing, respectively. The framework comprised four stages: tumor regions identification by multi-head self-attention (MSA) U-Net, nuclei segmentation by HoVer-Net, quantitative feature by handcrafted extraction, and differentiation and risk stratification classifier construction. Pixel accuracy, precision, recall, dice score, intersection over union (IoU) and area under the curve (AUC) were used to evaluate the performance of tumor segmentation model and classifiers. RESULTS: MSA-U-Net model detected tumor regions with 0.910 precision, 0.869 recall, 0.889 dice score and 0.800 IoU. The differentiation classifier achieved 0.977 ± 0.0159, 0.955 ± 0.0181, 0.885 ± 0.0237 AUC in D1, D2 and D3, respectively. The most discriminative features between BCC and TE contained Homogeneity, Elongation, T-T_meanEdgeLength, T-T_Nsubgraph, S-T_HarmonicCentrality, S-S_Degrees. The risk stratification model can well predict HR-BCC and LR-BCC with 0.920 ± 0.0579, 0.839 ± 0.0176, 0.825 ± 0.0153 AUC in D1, D2 and D3, respectively. The most discriminative features between HR-BCC and LR-BCC comprised IntensityMin, Solidity, T-T_minEdgeLength, T-T_Coreness, T-T_Degrees, T-T_Betweenness, S-T_Degrees. CONCLUSIONS: This framework hold potential for future use as a second opinion helping inform diagnosis of BCC, and identify nuclei and TME features related with malignancy and tumor risk stratification.

Diagnosis of Primary Cutaneous Amyloidosis by Rapid 4,6-Diamidino-2-Phenylindole Staining.

BACKGROUND: Quick and accurate diagnosis of primary cutaneous amyloidosis (PCA) may be difficult because its symptoms are often subtle and nonspecific. OBJECTIVE: We sought to review the literature on the roles of various staining methods in the diagnosis of amyloidosis and demonstrate added benefits of using rapid 4,6-diamidino-2-phenylindole (DAPI) staining in the diagnosis of PCA. METHODS: Three groups of cases, namely, PCA, neurodermatitis, and prurigo nodularis, were retrieved from a computerized pathology database for study, and their paraffin-embedded tissue blocks were cut following standard procedures. The tissue sections were stained with three stains: hematoxylin-eosin (HE), Congo red, and DAPI stains, and examined under the microscope to compare the staining patterns of these three methods. We also performed amyloid keratin and apolipoprotein E (APOE) staining on the sections of PCA in order to further support our conclusion. The PCA sections were read by junior and senior dermatopathologists for comparison. RESULTS: The sensitivity of DAPI staining for PCA was significantly higher than that of Congo red staining and HE staining (p < 0.001). This statement holds true whether the experiment was grouped in one sample or was divided into groups of junior and senior dermatopathologists (p < 0.001). The DAPI-positive staining areas, except for the nuclei, were consistent with the amyloid deposition areas. In this study, DAPI staining had a sensitivity of 98.6% and a specificity of 100%. CONCLUSION: DAPI staining could serve as a useful technique to establish the diagnosis of PCA, and its high efficacy in diagnosing PCA makes it less dependent on the experience levels of the evaluators. Additionally, the binding of DAPI to the A-T-rich sequence of double-stranded DNA suggests that amyloid may contain DNA or a similarly structured nucleic acid.

Cutaneous malakoplakia with verruciform xanthoma in the same lesion.

Cutaneous malakoplakia (CM) is a rare, chronic, granulomatous disease characterized histopathologically by Michaelis-Gutmann bodies (MGB). Verruciform xanthoma (VX) is a rare, benign lesion characterized histopathologically by epithelial papillomatous hyperplasia, local hyperkeratosis with incomplete keratosis, infiltration of foam cells and inflammatory cells in the papillary dermis. We present an elderly Chinese man with CM and coexisting VX with histological confirmation of MGB.

Buschke-Ollendorff syndrome with LEMD3 germline stopgain mutation p.R678* presenting as multiple subcutaneous nodules with mucin deposition.

Buschke-Ollendorff syndrome (BOS; OMIM 166700) is a rare autosomal dominant disorder characterized by the existence of connective tissue nevus and/or osteopoikilosis. The skin lesions usually present as firm, yellow, or flesh-colored papules and nodules, which may coalesce into plaques and increase in size and number over time. We present a case of a 26-year-old male with multiple subcutaneous nodules on the waist and thigh for more than 20 years. Being deeply seated, his skin lesions were not visible and could only be appreciated by palpation. Accordingly, pathology showed an increase in thick, crossed, or paralleled, elastic fibers arranged between the collagen bundles in the lower part of the reticular dermis and the subcutaneous fat with mucin deposition. Heterozygous point mutation in exon 8 of the LEMD3 gene was detected, which confirmed the diagnosis of BOS. The deeply situated nature of skin lesions noted in our case has not been reported in the literature of BOS. Our case thus expands the clinical and pathological features of the disease.

Histopathological diagnosis of persistent pruritic eruptions associated with adult-onset Still's disease.

AIMS: Persistent pruritic eruptions (PPEs), presenting with dyskeratotic keratinocytes histologically, are characteristic skin rash in patients with adult-onset Still's disease (AOSD). The lesions may be histologically similar to other entities that present with dyskeratosis. In the present study, we compared the histopathological features between PPEs and other entities presenting with dyskeratosis. METHODS AND RESULTS: To investigate whether histopathological findings can be used to discriminate among PPEs and other entities presenting with dyskeratotic keratinocytes, cutaneous histopathological changes of PPEs associated with AOSD (n = 26) were compared with those of systemic lupus erythematosus (SLE) (n = 16), dermatomyositis (n = 19), and drug eruption (n = 16). Dyskeratosis was observed in the upper one-third of the epidermal layer in all 26 PPEs. The rate of dyskeratosis for PPEs was higher than that for SLE (18.8%) and dermatomyositis (15.8%). In drug eruptions, the dyskeratotic cells were distributed in all levels of the epidermis. Variable densities of neutrophils were found in the dermis in all PPEs. CONCLUSIONS: Although this was a retrospective study conducted at a single centre, presentation of dyskeratotic keratinocytes in the upper one-third of the epidermal layer is a distinctive histopathological reactive pattern of PPEs. This pattern may be a useful histopathological marker for early diagnosis of AOSD.

Onychomycosis secondary to onychomadesis: an underdiagnosed manifestation.

Onychomycosis is a rare nail disorder in early childhood, while onychomadesis is a periodic idiopathic, non-inflammatory disease that affects the nail matrix and is common in children especially in those who suffer from viral infections. In this study, we investigated recent cases of onychomycosis subsequent to periods of onychomadesis in children. Sixteen young children (six males, 10 females) with a mean age of 36.5 months were diagnosed with onychomadesis, and 13 of the patients had a history of viral infection prior to nail changes. Direct microscopy of nail scaling was positive in 11 cases (68.8%), and culture was positive in the same number of cases. Four Candida species were isolated: Candida glabrata was the most frequent, found in eight cases (72.7%), while C. albicans, C. parapsilosis and C. tropicalis, each were encountered in a single case. All children were treated successfully with or without topical bifonazole therapy.

Diagnostic Criteria in Intraepithelial Pagetoid Neoplasms: A Histopathologic Study and Evaluation of Select Features in Paget Disease, Bowen Disease, and Melanoma In Situ.

BACKGROUND: Paget disease, Bowen disease, and malignant melanoma in situ are intraepidermal neoplasms, characterized by the presence of pagetoid scatter of atypical cells in the epidermis. This study reviewed the frequency of select histologic criteria to validate their usefulness in the histologic distinction between these entities. METHODS: One hundred forty-four specimens with the diagnosis of Bowen disease, 144 specimens with Paget disease (mammary and extramammary), and 144 specimens with malignant melanoma in situ were examined microscopically to define frequencies of select histologic criteria present in each disease. RESULTS: Comparison between mammary Paget and extramammary Paget disease showed no significant differences in the features studied. Crushing of basal keratinocytes, presence of atypical cells in the corneum, and presence of large cells with amphophilic cytoplasm were significantly noted in Paget disease. Transition between the atypical clear cells and surrounding keratinocytes was absent in all cases of melanoma in situ and in 87 (60.4%) cases of Paget disease, but it was significantly associated with Bowen disease (98.6%). Dyskeratotic cells were significantly associated with Bowen disease cases. CONCLUSION: Our study demonstrated a practical histologic approach to differentiate between intraepidermal pagetoid neoplasms. Careful histologic study of the proposed criteria may reduce reliance on immunohistochemical stains.

Pathologic features of anogenital precancerous high-grade squamous intraepithelial lesion (squamous cell carcinoma in situ).

BACKGROUND: Precancerous high-grade squamous intraepithelial lesion (HSIL), the current consensus terminology for anogenital squamous cell carcinoma in situ (SCCIS), often presents with distinctive histopathologic findings that may be a function of anatomic site or associated human papillomavirus infection. METHODS: Fifty-six specimens of anogenital HSIL were compared with an equal number of specimens of SCCIS from non-anogenital sites in regard to the presence of parakeratosis, flag sign in the stratum corneum, compact stratum corneum, hypergranulosis, koilocytes, small blue cells, clonal populations of keratinocytes, pagetoid scatter of atypical keratinocytes, clear cell change, glassy red cytoplasm, pigmentation, nuclear/cytoplasmic(N/C) ratio >2/1, nuclear hyperchromasia, pleomorphic nuclei, mitotic figures, abnormal mitotic figures, dyskeratotic keratinocytes, involvement of skin appendages, acantholysis and amyloid deposition. RESULTS: Hypergranulosis, koilocytes, small blue cells, pigmentation, nuclear hyperchromasia, dyskeratotic keratinocytes and amyloid deposition were more frequently noted in anogenital HSIL. Parakeratosis, clear cell change, pleomorphic nuclei, skin appendages involvement and acantholysis were strongly associated with non-anogenital location. There was no significant difference in the incidence of the remaining features. CONCLUSION: The strongest predicators of an anogenital location included hypergranulosis, koilocytes, small blue cells and nuclear hyperchromasia. Pigmentation and amyloid deposition were also strongly associated with an anogenital location.

Micronized acellular dermal matrix combined with platelet rich plasma in the treatment of atrophic acne scars: A self-controlled split face study.

BACKGROUND: Micronized acellular dermal matrix (mADM) can induce tissue regeneration and repair, and filling. OBJECTIVES: The efficacy and safety of (mADM) were evaluated in the treatment of atrophic acne scar. METHODS: In this single-blinded, self-controlled, split-face study, 16 patients (48 scar sites) were divided into treatment group (24 scar sites) and control group (24 scar sites). One side of the affected area was treated with mADM combined with platelet rich plasma (PRP) injection as the treatment group; the other side of the affected area was treated with PRP injection as the control group. The efficacy was evaluated by the Acne scar assessment scale (ASAS) and Acne Scar Weight Rating Scale (ECCA) 3 months after treatment. RESULTS: After 3-month treatment in 16 patients, the atrophic acne scars in both groups were all improved. The ASAS score and ECCA weight score in the treatment group was significantly lower than that in the control group (2.50 ± 0.51 vs. 3.62 ± 0.77 and 14.17 ± 10.18 vs. 31.88 ± 13.25; p < 0.001). LIMITATIONS: Short-term 3-month treatment period. Small sample size limits generalizability of results. CONCLUSION: The curative effect of mADM combined with PRP is significantly better than that of PRP alone.

Dynamic pathological analysis reveals a protective role against skin fibrosis for TREM2-dependent macrophages.

Rationale: Systemic sclerosis (SSc) is a chronic and incurable autoimmune disease with high mortality rates, and skin fibrosis is one of distinguishing hallmarks in the pathogenesis. However, macrophage heterogeneity regulating skin fibrosis remain largely unknown. Methods: We established mouse disease model and performed single-cell RNA-sequencing (scRNA-seq) to resolve the dynamic and heterogenous characteristics of macrophages in skin fibrosis, and the role of TREM2-dependent macrophages in the pathological process was investigated using knockout mice and intraperitoneal transferring TREM2+ macrophages combining with functional assays. Results: We show that TREM2-expressing macrophages (TREM2+ MФs) accumulate in injured skin of mice treated by bleomycin (BLM) and human SSc, and their gene signatures and functional pathways are identified in the course of disease. Genetic ablation of Trem2 in mice globally accelerates and aggravates skin fibrosis, whereas transferring TREM2hi macrophages improves and alleviates skin fibrosis. Amazingly, we found that disease-associated TREM2+ MФs in skin fibrosis exhibit overlapping signatures with fetal skin counterparts in mice and human to maintain skin homeostasis, but each has merits in skin remodeling and development respectively. Conclusion: This study identifies that TREM2 acts as a functional molecule and a major signaling by which macrophage subpopulations play a protective role against fibrosis, and disease-associated TREM2+ MФs in skin fibrosis might undergo a fetal-like reprogramming similar to fetal skin counterparts.