RESUMO
Two cases of melanotic neuro-ectodermal tumour of infancy (MNTI)--a rare neoplasm arising in the first year of life--are reported, with the results of immunohistochemical and ultrastructural examination. The tumours consisted of a biphasic cell population in a fibrous stroma. The small, darkly staining cells comprising the first population stained positively for synaptophysin, showing them to be neuroblasts, and the large epithelioid cells comprising the second cell population stained positively with the antibodies HMB-45 and NKI-Beteb, showing them to be melanocytes. Ultrastructural examination of the second case confirmed the biphasic nature of the tumour cells, with secretory granules and neurofilaments in the neuroblastic population, and melanosomes in the epithelioid population. These results add to the evidence supporting the neural crest origin of MNTI and confirm its formation from two distinct cell lines. Both cases have responded to local excision, with no recurrence more than a year after initial treatment.
Assuntos
Neoplasias Mandibulares/patologia , Neoplasias Maxilares/patologia , Tumor Neuroectodérmico Melanótico/patologia , Antígenos de Neoplasias/análise , Antígenos de Superfície/análise , Linhagem da Célula , Células Epitelioides/patologia , Células Epitelioides/ultraestrutura , Seguimentos , Humanos , Imuno-Histoquímica , Lactente , Masculino , Neoplasias Mandibulares/ultraestrutura , Neoplasias Maxilares/ultraestrutura , Melanócitos/patologia , Antígenos Específicos de Melanoma , Proteínas de Neoplasias/análise , Recidiva Local de Neoplasia , Crista Neural/patologia , Tumor Neuroectodérmico Melanótico/ultraestrutura , Neurônios/ultraestrutura , Sinaptofisina/análiseRESUMO
Although the incidence of multifocal epithelial tumours of the minor salivary glands is very low, canalicular adenoma not infrequently presents as a multifocal lesion, usually in the upper lip. We present an unusual case of bilateral multifocal canalicular adenomas of the buccal mucosa in a woman aged 75 years.