The research team, led by Biagio Scotti, followed the PRISMA guidelines for systematic reviews and prospectively registered their protocol in PROSPERO before searching four major databases — PubMed, Scopus, Web of Science, and the Cochrane CENTRAL register — from their inception through April 2025. Out of 277 records initially identified, 28 articles survived rigorous screening and made it into the final analysis. Every included case had to have a diagnosis confirmed by histopathology, the microscopic examination of tissue that remains the gold standard, and had to report dermoscopic or confocal findings. Two investigators independently screened the literature, with disagreements resolved by a third senior reviewer.

The cohort skewed toward the malignant end of the spectrum: 37 of the 71 tumors, or 52 percent, were sebaceous carcinomas, while 23 (32 percent) were sebaceous adenomas and 11 (16 percent) were sebaceomas. The patients were predominantly older, with a median age of 66 years, and 40 percent were female. Ten patients — 18 percent of the cohort — carried a diagnosis of Muir-Torre syndrome, a hereditary condition linked to mutations in DNA mismatch-repair genes such as MSH2 and MLH1 that predisposes carriers to sebaceous tumors and colorectal and other internal cancers. Notably, the review found no dermoscopic or clinical pattern that reliably distinguished syndromic tumors from sporadic ones, a finding the authors attribute to the small number of reported cases.

The anatomical distribution of the tumors offered its own clues. Sebaceomas clustered on the head and neck in 55 percent of cases, and sebaceous carcinomas did so even more strongly, at 76 percent — a reflection of the fact that roughly three-quarters of sebaceous carcinomas arise in or around the eye, where they carry a higher metastatic risk. Sebaceous adenomas, by contrast, favored the trunk, appearing there in 61 percent of reported cases. Malignant tumors were also simply bigger: sebaceous carcinomas averaged 16 by 12 millimeters, compared with roughly 10 by 8 millimeters for sebaceomas and 9 by 8.5 millimeters for adenomas. Ulceration, a sign of aggressive growth, was documented in 79 percent of carcinomas but only about 60 percent of the benign lesions.

The dermoscopic findings form the heart of the study. Dermoscopy is a technique in which a handheld microscope, often with polarized light, is pressed against or held just above the skin, revealing structures invisible to the naked eye. In the benign tumors, one pattern dominated: a uniform pinkish background — seen in 96 percent of sebaceous adenomas and 70 percent of sebaceomas — combined with monomorphic, orderly vessels, particularly elongated crown vessels that radiate toward the lesion’s edge without crossing its center, and arborizing vessels that branch like tree limbs. Crown vessels appeared in 57 percent of adenomas and 30 percent of sebaceomas, but in only 5 percent of carcinomas, where they were merely one component of a chaotic mixture.

Sebaceous carcinoma, by contrast, announced its malignancy through vascular anarchy. A polymorphic vascular pattern — meaning multiple different vessel shapes coexisting in the same lesion — was present in 28 of 37 carcinomas. Linear irregular vessels, mildly curved capillaries of varying length and caliber that are classic markers of malignant tumors such as amelanotic melanoma, appeared in a striking 89 percent of carcinomas, versus just 13 percent of adenomas and 10 percent of sebaceomas. Arborizing vessels showed up in 57 percent of carcinomas, often large, dilated, and poorly focused. The authors interpret this vascular chaos as the dermoscopic fingerprint of neoangiogenesis — the disorganized sprouting of new blood vessels that growing cancers require to feed themselves.

The famous yellow coloration of sebaceous lesions, long taught as the hallmark of oil-cell differentiation, emerged from the review with a more nuanced verdict. Yellow structureless areas were indeed common across all three tumor types — 61 percent of adenomas, 50 percent of sebaceomas, and 54 percent of carcinomas — supporting their role as a marker of sebaceous differentiation. But the review catalogues a long list of impostors that can produce the same hue, from juvenile xanthogranuloma and mastocytoma to lipidized dermatofibroma, pilomatricoma, keratoacanthoma, and even nodular melanoma. Yellow, in other words, is suggestive but never diagnostic, and its shade depends on whether the underlying material is lipid, which appears bright yellow, or keratin and necrotic debris, which read darker and more orange.

Reflectance confocal microscopy, a laser-based technique that images living skin at near-cellular resolution without a biopsy, added a tantalizing but incomplete layer. In the handful of cases where it was applied, RCM could visualize the defining cell of these tumors: the sebocyte, a cuboidal cell with a dark nucleus and a hyper-refractive, glistening cytoplasm packed with lipid. In Muir-Torre-associated adenomas, investigators described aggregates of these ovoid bright cells, along with dark spaces corresponding to sebaceous ducts surrounded by lobules. Yet the technique’s accuracy is limited — low cell density, inflammation, and overlying keratin can obscure the picture entirely, and in one reported sebaceoma the confocal features actually mimicked basal cell carcinoma, complete with nuclear streaming and peripheral palisading.

Several subtler dermoscopic signs also proved informative. Shiny white lines, caused by birefringent collagen under polarized light, occurred exclusively in sebaceous carcinomas — 8 of the 72 analyzed lesions — where they correspond histologically to fibrous septa between tumor nests, reinforcing the known link between tumor-associated fibrosis and malignant progression. Purplish globules, signaling hemorrhage, appeared in about a quarter of carcinomas, consistent with their intrinsic bleeding tendency. Brown-grey clods, reflecting melanin or melanophages, were absent from adenomas but present in sebaceomas, including cases in patients with darker Fitzpatrick skin types IV and V — an important observation, since in pigmented skin the classic yellow and vascular cues can be muted or absent altogether.

The practical message for clinicians is a two-step algorithm grounded in pattern recognition. A small, pink, homogeneous papule with orderly crown or arborizing vessels confined to the periphery points toward a benign sebaceous tumor, though the overlap between sebaceoma and adenoma is such that histopathology remains essential for distinguishing them. A larger, ulcerated lesion with polymorphic vessels — especially linear irregular and arborizing vessels crossing a yellow-white background — should raise immediate suspicion of sebaceous carcinoma and prompt biopsy. The authors are candid about the limitations: the evidence base consists of case reports and small series, only six patients in the entire cohort had Fitzpatrick skin types IV or V, and no standardized diagnostic criteria yet exist. They call for prospective validation across diverse skin types and for formal consensus criteria, so that the vascular signatures documented here can one day be applied with confidence in the clinic — potentially catching a deadly cancer while it is still a yellow bump on the surface.

Subject of Research: Dermoscopic and reflectance confocal microscopic features of sebaceous tumors including sebaceoma, sebaceous adenoma, and sebaceous carcinoma

Article Title: Dermoscopic and reflectance confocal microscopic features of sebaceoma, sebaceous adenoma and sebaceous carcinoma: a systematic review

Article References: Scotti, B., Baraldi, C., Veneziano, L., Magnaterra, E., Venturi, F., Vaccari, S., & Dika, E. (2026). Dermoscopic and reflectance confocal microscopic features of sebaceoma, sebaceous adenoma and sebaceous carcinoma: a systematic review. Archives of Dermatological Research, 318(1), Article 501. https://doi.org/10.1007/s00403-026-04953-5

Image Credits: AI Generated

DOI: 10.1007/s00403-026-04953-5

Keywords: sebaceous tumors, sebaceoma, sebaceous adenoma, sebaceous carcinoma, dermoscopy, reflectance confocal microscopy, skin cancer, Muir-Torre syndrome, crown vessels, linear irregular vessels, neoangiogenesis, dermatology

The clinical stakes are considerable. Although meibomian gland carcinoma accounts for only about 5 to 10 percent of eyelid tumors, reported mortality rates range from 15 to 25 percent, a striking figure for so uncommon a disease. The tumor arises from the meibomian glands, modified sebaceous structures embedded in the tarsal plate of the eyelid, and it behaves badly in every sense. It grows in a multifocal pattern, spreads along the conjunctival epithelium in a characteristic skip or jump fashion that leads surgeons to underestimate its true extent, and frequently returns after resection with positive margins. Once it reaches lymph nodes or distant organs, five-year disease-specific survival falls below 30 percent. Clinicians widely regard it as the most difficult eyelid tumor to diagnose and manage.

Part of the difficulty is that the tumor’s lineage identity is fragile outside the body. Meibomian gland cells carry lipid-rich cytoplasm, terminal sebaceous differentiation programs, and tightly regulated androgen receptor-dependent transcription networks. Under conventional two-dimensional culture conditions these features collapse quickly, producing dedifferentiated cells that no longer resemble the tumor the surgeon removed. The only published human meibomian gland carcinoma cell line, established by Zhang and colleagues, could be maintained for roughly 20 passages before fibroblast overgrowth took over, a familiar failure mode of primary culture. Most of what is known about the disease therefore comes from retrospective clinicopathological studies and static immunohistochemistry of formalin-fixed specimens, which capture structure but not function.

Therapeutic progress has been equally constrained. Conventional chemotherapy agents, including platinum compounds, taxanes, 5-fluorouracil, and mitomycin C, achieve modest response rates and rarely deliver durable control in advanced disease. Genomic profiling studies have identified recurrent alterations in PTGS2, HER2, PIK3CA, and PTEN, along with Hedgehog signaling changes and DNA mismatch repair defects, but without functional platforms to validate these findings, they have not translated into targeted therapies. The authors argue that the absence of scalable, patient-derived models preserving lineage identity, tumor heterogeneity, and functional plasticity has become the central bottleneck in the field, a greater obstacle than the lack of genomic data itself.

Conditional reprogramming, first described by Liu and colleagues in 2012, offers a way around this bottleneck. The technique co-cultures primary epithelial cells with gamma-irradiated mouse 3T3-J2 feeder fibroblasts in F/2 medium supplemented with the Rho-associated kinase inhibitor Y-27632. ROCK inhibition prevents anoikis and cytoskeletal tension-induced apoptosis, while the feeder layer supplies paracrine signals and extracellular matrix components that sustain epithelial survival. Together these inputs converge on pathways governing actin dynamics, cell-cell adhesion, and stress responses, effectively decoupling proliferative capacity from terminal differentiation. The result is a reversible, non-neoplastic, stem-like proliferative state: cells divide furiously, yet they retain lineage-specific transcriptional programs and genomic integrity, and they are not driven toward malignant transformation.

The numbers are remarkable. Conditional reprogramming cultures expand 10 to 100 times faster than conventional epithelial cultures, yielding between 100 million and a billion cells from a 2-millimeter biopsy in under three weeks. Multiple studies have documented high genomic fidelity across extended passages, including preserved variant allele frequencies and an absence of de novo chromosomal aberrations. Equally important is reversibility: remove the feeder layer or the ROCK inhibitor and the cells promptly exit the proliferative state, re-engage native differentiation programs, and rebuild tissue-specific architecture. This distinguishes the method from induced pluripotent stem cell reprogramming and oncogene-based immortalization, both of which erase lineage memory. The system can also generate matched tumor and adjacent normal epithelial cultures from the same patient, creating isogenic pairs that minimize inter-individual genetic variability and allow direct comparison of oncogenic signaling and drug responses.

Over the past decade the platform has proven itself across epithelial cancers. In bladder cancer, Kettunen and colleagues showed that ex vivo drug-response profiles from conditionally reprogrammed cells concorded with clinical outcomes in a personalized screening platform paired with patient-derived xenografts. In prostate cancer, paired tumor and normal cultures revealed tumor-selective synergy between docetaxel and radiation, defining a therapeutic window that spares healthy epithelium. In colorectal cancer, a dose-response matrix approach assessed combined sensitivity to 5-fluorouracil and oxaliplatin, marking the first functional assay to guide adjuvant chemotherapy selection in that disease. Large-scale biobanks built with the technology, including more than 120 head and neck squamous carcinoma lines coupled to whole-exome sequencing and a gastric cancer repository spanning 32 patients, demonstrate its scalability for rare specimens.

Ophthalmic applications have been slower to arrive but are encouraging. Conditionally reprogrammed human limbal epithelial cells have maintained normal karyotype and stable drug-toxicity profiles across passages, validating their use in ocular surface safety screening. The technology has converted human fibroblasts into retinal pigment epithelium-like cells within two weeks, far faster than pluripotent stem cell protocols, and has sustained papillomavirus-positive canine eyelid epithelium for antiviral testing. In conjunctival fornix epithelial cells, the mucolytic drug bromhexine stimulated MUC5AC secretion and lipid-droplet production, hinting at therapeutic targets for ocular lubrication disorders. Most relevant to eyelid oncology, Lee and colleagues used conditional reprogramming to generate the first authenticated trio of ocular adnexal sebaceous carcinoma lines, preserving patient-specific mutations, adipophilin-positive lipid vacuoles, and MYC overexpression, with full validation by short tandem repeat profiling and next-generation sequencing within five passages. Functional testing of mitomycin C, 5-fluorouracil, and the glutamine-metabolism inhibitor DON each induced dose-dependent apoptosis and differentiation, an immediate proof of concept in a historically model-poor disease.

For meibomian gland carcinoma specifically, the review describes a practical workflow. Fresh surgical specimens are minced and enzymatically dissociated, then seeded onto irradiated 3T3-J2 feeder layers in Y-27632-supplemented medium. Validation relies on immunophenotypic markers including cytokeratins, epithelial membrane antigen, androgen receptor, adipophilin, Ki-67, and p63, alongside functional assays in which withdrawal of the ROCK inhibitor tests whether lipid metabolism and sebaceous differentiation can be restored. The authors also stress structured quality control: short tandem repeat authentication, histological correlation with the parental tumor, confirmation of driver alterations and copy-number profiles, longitudinal tracking of tumor-specific variants, and defined passage limits. Such measures guard against the field’s known pitfalls, including preferential expansion of non-malignant epithelium, clonal selection in small biopsies, and possible epigenetic drift during prolonged culture.

Limitations remain real. The mouse feeder layer introduces interspecies signaling that complicates interpretation, and the cultures lack the immune, stromal, and vascular components of the native tumor microenvironment, restricting studies of immune evasion and therapy-induced immune modulation. The authors propose mitigation through pathology-guided sampling, tumor-cell enrichment, molecular monitoring, and the development of feeder-free and hybrid co-culture systems. Looking ahead, they envision conditional reprogramming serving as the upstream expansion step that feeds organoid culture, patient-derived xenografts, multi-omics profiling, and artificial intelligence-assisted analysis of drug-response matrices and imaging phenotypes. In a disease too rare for randomized trials, where surgical specimens are small and fragmented and engraftment rates in xenograft models are low, that combination could anchor functional precision oncology, guide eye-sparing treatment strategies, and finally give clinicians a way to test therapies on living cells from the very tumors they are trying to beat.

Subject of Research: Use of conditional reprogramming cell culture technology to develop patient-derived preclinical models of meibomian gland carcinoma and other eyelid tumors.

Article Title: Conditional reprogramming in eyelid tumors: bridging the model gap in meibomian gland carcinoma

Article References: Conditional reprogramming in eyelid tumors: bridging the model gap in meibomian gland carcinoma. (n.d.). https://doi.org/10.1007/s44272-026-00057-3

Image Credits: AI Generated

DOI: 10.1007/s44272-026-00057-3

Keywords: conditional reprogramming, meibomian gland carcinoma, eyelid tumors, sebaceous carcinoma, patient-derived models, ROCK inhibitor, precision oncology, drug sensitivity testing, ocular oncology, organoids, tumor biobanking, translational research