RESUMO
Merkel cell carcinoma (MCC) is an extremely rare and aggressive tumor. Here we report an unusual MCC that manifested as an abruptly enlarging, painful skin lesion over the right antecubital fossa and masqueraded as an epidermal cyst in a 42-year-old male. The lesion was surgically excised and subjected to histopathologic and immunohistochemical examinations. The subsequent analysis allowed for the diagnosis of MCC. Clinicians should always be cognizant of MCC, which can be easily misdiagnosed. Early diagnosis and appropriate treatment are keys to improving the survival rates of MCC patients.
RESUMO
Indirect triple immunolabelling techniques were used to identify the presence of choline acetyl-transferase (ChAT), neuronal nitric oxide synthase (nNOS), Dopamine beta-hydroxylase (DβH), neuromedin U-8 (NMU-8), and neuropeptide Y (NPY) in the ganglionated plexuses of the human gallbladder. Of all the intrinsic cholinergic neurons examined, NMU-8-immunoreactive (-IR) neurons appeared to be the most populous, followed closely by neurons containing NPY-IR. nNOS-IR neurons were often observed to coexist with ChAT, NMU, and NPY. Occasionally, these nNOS positive neurons were seen triple labeled with ChAT, NMU-8, and NPY. Results also indicate that not all nNOS and NMU-8-IR coexistent neurons express NPY immunoposi-tivity. Our findings suggest that these intrinsic neurons may be categorized into a distinct population of neurons that express both inhibitory and excita-tory capabilities.Intrinsic cholinergic neurons that were ChAT-IR displayed a spectrum of immunopositivity. Interestingly, a small subpopulation of these neurons ap-peared to be extremely weak ChAT-IR or simply ChAT-immunonegative. These occasionally obser-ved ChAT-immunonegative neurons at times ex-pressed single immunopositivity for NMU-8 or nNOS, while more frequently, these ChAT-immunonegative neurons were found to be single immunopositive, or at times, double immunopositi-ve for NMU-8-, NPY-, or nNOS-IR.Dopamine beta-hydroxylase (DβH) antibodies were used to confirm the lack of intrinsic sympat-hetic innervation in the human gallbladder. As suspected, in all the sections examined, DβH-IR neu-rons were not detected. The only indication of DβH immunopositivity was noted among delicate fibers surrounding the neurons and blood vessels within the organ
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