Non-Melanoma Skin Cancer (NMSC)

C44WHO — Skin Tumours

Skin

Prognosis

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🔬 Histological Types

📚 Latest Research

2026-09-10

The mechanism of malignant progression in extramammary Paget's disease (EMPD): hallmarks of EMPD.

Kajihara I

A new review identifies the key molecular hallmarks driving malignant progression in extramammary Paget's disease (EMPD), a rare apocrine-gland skin cancer of the genital and axillary regions. The HER2/PI3K/AKT signaling cascade and hormone receptor pathways are aberrantly activated, while driver gene mutations in ERBB2 and PIK3CA are recurrently detected despite an overall low tumor mutation burden. The tumor microenvironment actively suppresses anti-tumor immunity by reducing CD4+ and CD8+ T cells while expanding Treg cells and CD163+ macrophages, with the enhanced Warburg effect and Staphylococcus aureus colonization further dampening immune responses. These insights into EMPD's high intratumor genetic heterogeneity and immune-evasion strategies may guide the development of targeted and immunotherapeutic treatment options for this poorly understood malignancy.

Medical molecular morphology

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2026-09-09

The utility of electron microscopy in dermatopathology: cutaneous SMARCA4-deficient dedifferentiated large cell neuroendocrine carcinoma.

Jiang KJ, et al

Electron microscopy has confirmed the first two reported cases of cutaneous SMARCA4-deficient large cell neuroendocrine carcinoma (SD-LCNEC), a tumour type previously described almost exclusively as a thoracic malignancy. The two patients — a 59-year-old male with a 3 cm right flank subcutaneous nodule and concurrent pulmonary mass with cervical lymph node metastases, and a 56-year-old female with a painful 5 × 10 cm ulcerated left perineal mass and concurrent pulmonary small cell carcinoma — both showed markedly reduced neuroendocrine marker expression on immunohistochemistry, rendering IHC-based classification as LCNEC impossible. Ultrastructural examination of formalin-fixed paraffin-embedded tissue revealed abundant membrane-bound dense-core neurosecretory granules and well-formed desmosomes in both cases, ultrastructurally confirming the neuroendocrine diagnosis. These findings demonstrate that electron microscopy remains an indispensable diagnostic tool for rare, dedifferentiated neuroendocrine malignancies when immunohistochemistry fails.

Ultrastructural pathology

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2026-09-08

High-Risk Characteristics of Eyelid Basal Cell Carcinoma in Young Patients: A Retrospective Cohort Study.

Bez M, et al

Young adults under 40 with eyelid basal cell carcinoma (BCC) experienced a crude local recurrence rate of 22.2%, nearly four times the 5.8% rate observed in patients aged 40 and older, though this difference attenuated after statistical adjustment for histological subtype and clinical features. In this retrospective cohort of 268 patients, the 45 younger patients were more often female (64.4% vs. 43.9%), more frequently reported indoor tanning (35.6% vs. 7.6%), and more often carried a genetic syndrome (8.9% vs. 0.0%). Their tumors more commonly involved the critical eyelid margin (64.4% vs. 23.3%), had positive initial surgical margins (68.9% vs. 35.4%), and required revision surgery stages (73.3% vs. 17.5%), while postoperative dry eye syndrome was also markedly more common (26.7% vs. 4.0%). These findings indicate that early-onset eyelid BCC presents with a distinct high-risk profile driven by aggressive tumor anatomy and specific exposure patterns rather than age alone, underscoring the need for intensified surgical planning and long-term surveillance in young patients.

Ophthalmology and therapy

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