Skin
Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard in Toxicologic Pathology, 2018
In the epidermis, Merkel cells are scattered among the keratinocytes of the basal cell layer, and are attached by desmosomes to keratinocytes and have processes that interdigitate with proximal keratinocytes. Merkel cells have nuclei that are deeply indented with dense cytoplasm containing intermediate cytokeratin filaments. A characteristic feature of Merkel cells is the presence of dense-core vesicles located in the perinuclear zone and cytoplasmic processes near nerve fibers. Unmyelinated sensory nerve fibers penetrate the basal lamina to lie adjacent to Merkel cells forming Merkel cell-neuron complexes that serve as mechanoreceptors. Merkel cells may also release neurocrine-like substances (e.g., serotonin and substance P). Positive immunoreactivity for cytokeratin 20 is highly specific for Merkel cells in skin (Halata et al. 2003).
Clinical Features of Colorectal Adenoma and Adenocarcinoma
Peter Sagar, Andrew G. Hill, Charles H. Knowles, Stefan Post, Willem A. Bemelman, Patricia L. Roberts, Susan Galandiuk, John R.T. Monson, Michael R.B. Keighley, Norman S. Williams in Keighley & Williams’ Surgery of the Anus, Rectum and Colon, 2019
Others have used reverse transcriptase-polymerase chain reaction (RT-PCR) to detect CEA expression of carcinoma cells in lymph nodes. They have demonstrated that this method, which detects DNA, is far more sensitive than conventional techniques in revealing micrometastases. PCR has also been used in this way to detect mutations in K-ras and the APC gene with similar results. Unfortunately, not all tumours express these mutations, and CEA expression is non-specific. We at the Royal London, therefore, took an alternative path and used RT-PCR to detect and quantify cytokeratin-20 (CK-20) in the lymph nodes of specimens removed from patients with colorectal cancer. Cytokeratin-20 was chosen since it was thought to be expressed selectively by the epithelial cells derived from the large intestine; thus, if detected, suggested invasion by cancer cells derived from the colorectal cancer. Despite initial enthusiasm because of high sensitivity in detection of CK-20 and indeed other molecular markers, there was a lack of specificity, which made the technique impractical as a means of detecting occult metastases. Whilst further work is needed, a meta-analysis of available data assessing these techniques suggests cytokeratin, K-12 Ras mutation, c-MET, CEA, guanylyl cyclase (2)C and/or melanoma antigen gene-A3 may be appropriate markers. Detection of these biomarkers in histopathologically negative nodes is associated with an increased risk of disease recurrence and poor survival.166
Merkel Cell Carcinoma
Dongyou Liu in Tumors and Cancers, 2017
MCC is confirmed through a series of immunohistochemical assays, of which cytokeratin 20 (CK20) positivity is the most discriminating feature (in 89%–100% of MCC), and only rarely positive in small cell lung carcinoma [SCLC]). Tumors may also be screened for markers that are common to SCLC, lymphoma, and melanoma in order to rule out these more common cancers. MCC cells can express both neuroendocrine and epithelial proteins, and proliferation markers are frequently seen.
A case series of Merkel cell carcinoma of the eyelid: a rare entity often misdiagnosed
Published in Orbit, 2019
Adriana Iuliano, Fausto Tranfa, Lidia Clemente, Federica Fossataro, Diego Strianese
A 68-year-old diabetic woman was admitted to our Orbit Unit with two painful, fast-growing, and protruding masses, located in the left upper eyelid (Figure 1(2a)). The smallest one was firm and mobile, while the biggest one firm and fixed. She had no history of cancer. A previous orbital magnetic resonance (MR) imaging showed two confluent homogenous soft tissue masses of the eyelid sparing the ocular globe, characterized by mild enhancement after intravenous contrast injection. A 1.7 × 1.4 cm violaceous lozenge skin was surgically removed. Full thickness excision and eyelid reconstruction with a flap from the lower lid (Cuttler-Beard flap) were performed (Figure 1(2b)). Neither lagophthalmos nor corneal exposure were detectable after surgery. Histological examination showed many mitoses and cells with irregular hyperchromatic nuclei. Immunohistochemical analysis was positive for cytokeratin 20 and CD56, confirming MCC. Tumor margins were negative. A total body positron emission tomography/computed tomography (PET/CT) scan, performed for systemic work-up, showed only a mild aspecific captation in the pharyngeal district. Moreover, ultrasound examination (US) of the neck revealed no pathological lymph nodes. The lesion was staged as T2bcN0M0/T1N0M0 according to the AJCC TNM staging system for both eyelid carcinoma and MCC, 7th edition. The patient is currently on follow up (8 months) without evidence of local or systemic recurrence.
Current and emerging bladder cancer biomarkers with an emphasis on urine biomarkers
Published in Expert Review of Molecular Diagnostics, 2020
Antonio Lopez-Beltran, Liang Cheng, Thomas Gevaert, Ana Blanca, Alessia Cimadamore, Matteo Santoni, Francesco Massari, Marina Scarpelli, Maria R. Raspollini, Rodolfo Montironi
Nicotinamide N-methyltransferase is highly expressed in urothelial bladder carcinoma and correlates with pathologic grade [31]. Apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE/Ref-1) levels are higher in urothelial bladder carcinoma concerning non- urothelial carcinoma and correlate with tumor grade and stage, and it is highly expressed also in patients with recurrent bladder carcinoma [32]. The Aura Tek FDP TestTM in urine can detect urothelial bladder carcinoma recurrence [4]. The activated leukocyte cell adhesion molecule (ALCAM), a cell adhesion molecule, positively correlates with tumor stage and overall survival, after adjusting for patients, clinical features and Bacillus Calmette-Guerin treatment [30]. The cytokeratin-20 (CK20) urine RT-PCR assay shows 78–87% sensitivity and 56–80% specificity for the detection of urothelial bladder carcinoma, with improved diagnostic accuracy in tumor progression [33] but as a limitation, it has poor performance for low-grade tumors. High levels of CK8 and CK18 detected in the urine by UBC Rapid test allows to separate high- vs low-grade urothelial bladder carcinoma [35].
Merkel cell carcinoma in the hand. Report of two cases
Published in Case Reports in Plastic Surgery and Hand Surgery, 2022
Felipe Mesa, Marcela Cardona, Carolina Mesa, Rodrigo Restrepo, Juan Andrés Echeverri
68-year-old female, with a mass on the dorsum of the proximal phalanx of the right fourth finger of 1 × 0.8 × 0.8 cm, slow growth, asymptomatic and purple in color (Figure 3). The biopsy reported a malignant soft tissue lesion, characterized by masses of cells with a basaloid appearance with a vesicular nucleus, without nucleolus and a pattern of fine chromatin in salt and pepper, accompanied by scant cytoplasm and with a high mitotic rate, separated by tissue trabeculae. Connective and with areas of necrosis (Figure 4), immunohistochemistry showed intensely positive cytokeratin 20 in a cytoplasmic spot staining pattern, negative cytokeratin 7, and intensely positive synaptophysin (Figures 5 and 6).
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