Dermatopathology, Volume 12, Issue 3 (September 2025) – 6 articles

Pilomatricomas are benign tumors originating from hair follicle matrix cells and represent the most common skin tumors in pediatric patients. Pilomatricomas may be associated with genetic syndromes such as myotonic dystrophy, familial adenomatous polyposis (FAP), Turner syndrome, Rubinstein–Taybi syndrome, Kabuki syndrome, and Sotos syndrome. This study reviews the literature on pilomatricomas occurring in syndromic contexts and presents a novel case linked to Apert syndrome. A systematic review was conducted using PubMed and Cochrane databases, focusing on case reports, case series, and reviews describing pilomatricomas associated with syndromes. A total of 1272 articles were initially screened; after removing duplicates and excluding articles without syndromic diagnoses or lacking sufficient data, 81 full-text articles were reviewed. Overall, 96 cases of pilomatricomas associated with genetic syndromes were identified. Reports of patients with Apert syndrome who do not develop pilomatricomas are absent in the literature. Pilomatricomas predominantly affect pediatric patients, with a slight female predominance, and are often the first manifestation of underlying genetic syndromes. Our study highlights previously unreported associations of pilomatricoma with Apert syndrome, providing molecular insights. This study contributes to understanding the clinical and molecular features of pilomatricomas in syndromic contexts and underscores the importance of genetic analysis for accurate diagnosis and management. Full article

Whether the spongiotic reaction caused by the interaction of keratinocytes, T-lymphocytes, inflammatory dendritic epidermal cells (IDECs), and Langerhans cells (LCs) observed in atopic dermatitis (AD) represents a common feature of spongiosis in various skin diseases remains unclear. We analyzed the characteristics of spongiosis in AD compared with those in other eczematous dermatitis and inflammatory skin diseases by using immunohistochemical methods. Infiltration of IDECs (CD11c+ cells and/or CD206+ cells) and T-lymphocytes, accompanied by degenerated keratinocytes and aggregated LCs (CD207+ cells), was frequently observed as a common feature of spongiosis in multiple conditions. However, IDECs expressing IgE were identified exclusively in IgE-mediated AD. Aggregation of IDECs was predominantly observed in the spongiosis of adaptive immune-mediated eczematous disorders, such as AD and allergic contact dermatitis. These IDEC aggregations constituted the major components of the epidermal dendritic cell clusters seen in AD and other eczematous or eczematoid dermatoses, and may serve as a useful distinguishing marker from Pautrier collections seen in cutaneous T-cell lymphoma. These findings suggest that IDECs, in cooperation with other immune cells, may play a pivotal role in spongiosis formation in AD and various skin diseases, although the underlying immunopathological mechanisms differ among these conditions. Full article

In this review, we explore the complexities of objectively assessing the response to immunotherapy in mycosis fungoides (MF), a prevalent form of cutaneous T-cell lymphoma. The core challenge lies in distinguishing between reactive and malignant lymphocytes amidst treatment, particularly given the absence of uniform pathological biomarkers for MF. We highlight the vital role of emerging histological technologies, such as multispectral imaging and spatial transcriptomics, in offering a more profound insight into the tumor microenvironment (TME) and its dynamic response to immunomodulatory therapies. Drawing on parallels with melanoma—another immunogenic skin cancer—our review suggests that methodologies and insights from melanoma could be instrumental in refining the approach to MF. We specifically focus on the prognostic implications of various TME cell types, including CD8+ tumor-infiltrating lymphocytes, natural killer (NK) cells, and histiocytes, in predicting therapy responses. The review culminates in a discussion about adapting and evolving treatment response quantification strategies from melanoma research to the distinct context of MF, advocating for the implementation of novel techniques like high-throughput T-cell receptor gene rearrangement analysis. This exploration underscores the urgent need for continued innovation and standardization in evaluating responses to immunotherapies in MF, a field rapidly evolving with new therapeutic strategies. Full article

A 29-year-old gentleman of African descent presented to the emergency department with a three month history of a rash affecting the trunk, upper limbs, and thighs. The patient was unsure of any triggers and denied any preceding illness, new medications, illicit drug use, or recent vaccinations. On examination, there was a widespread papulosquamous eruption characterised by scaly, hyperpigmented papules and plaques involving the trunk, upper arms, and upper thighs. A definitive diagnosis was established through a diagnostic skin biopsy of a fresh lesion. Full article

Background: We present an interesting case involving a tumour comprising both basal cell tumour cells and sarcomatoid tumour cells. An 86-year-old woman presented with an erythematous lesion on her left cheek. Clinical and dermoscopic findings suggested BCC. Complete excision and histopathological examination revealed a BCC with a separate proliferation of atypical spindle and epithelioid cells. Immunohistochemical staining supported the diagnosis, with basaloid cells positive for CK5/6 and Ber-EP4 and sarcomatoid cells positive for CD10 and vimentin. Results: Histology and immunohistochemistry confirmed a basal cell carcinoma with sarcomatoid differentiation. The close proximity of sarcomatoid cells to the BCC component suggests a potential role of epithelial–mesenchymal interactions in tumour development. Further investigations into the exact origin of this tumour are required. Conclusion: Basal cell carcinoma with sarcomatoid differentiation is rare. This case highlights the importance of thorough histological and immunohistochemical evaluation. Further studies are necessary to better understand the pathogenesis of such collision tumours. Full article

Penile intraepithelial neoplasia (PeIN) is a rare but clinically significant condition that can progress to invasive squamous carcinoma. Early diagnosis is crucial but often challenging due to its heterogeneous clinical and dermoscopic presentation, which can mimic other benign or malignant lesions. In this study, we report two cases of pigmented penile lesions evaluated using non-invasive imaging techniques: reflectance confocal microscopy (RCM) and line-field confocal optical coherence tomography (LC-OCT). Both methods revealed characteristic features such as hyperkeratosis, parakeratosis, acanthosis, nuclear pleomorphism of keratinocytes, and the presence of bright intraepithelial dendritic cells, correlating closely with histopathological findings of high-grade basaloid PeIN. Our findings highlight the valuable role of RCM and LC-OCT in improving the differential diagnosis of genital lesions, potentially reducing the need for invasive diagnostic procedures and ensuring early, appropriate management. Full article