RESUMEN
Amelanotic malignant melanoma (AMM) is rare in the oral region. The present study examined the clinical features of this tumor in an attempt to establish diagnostic criteria. The expression of three melanocytic differentiation markers, HMB-45, S-100 and Melan-A, was also measured in primary oral AMMs in order to determine whether the markers could be used to diagnose primary oral AMMs and to find out which marker was the most sensitive. It may be particularly difficult to correctly diagnose AMM that lacks a radial growth phase without immunohistochemical assistance. In the present study, mixtures of polygonal and spindle cells at different ratios were observed in the tumors with and without a radial growth phase. Immunohistochemistry was used to examine the HMB-45, S-100 and Melan-A expression in the formalin-fixed paraffin-embedded specimens of primary oral AMMs. Comparison of staining intensities (SIs) and labeling indices (LIs) of the markers was also performed. The immunostaining results revealed that the SI of Melan-A was significantly higher than that of S-100 (P=0.0011). HMB-45, S-100 and Melan-A also exhibited high positive rates and LIs in AMMs and, therefore, may be good markers for the immunohistochemical diagnosis of primary oral AMMs. Furthermore, Melan-A may be a more sensitive marker than S-100 and HMB-45, as it has a higher SI.
RESUMEN
We describe a case presenting with facial and hypoglossal nerve paresis due to cortical cerebral infarction. A 54-year-old man visited our hospital complaining of sudden episode of dysarthria and facial paresis. Neurological findings revealed tongue deviation to the left and left facial paresis with forehead wrinkling while neither limb paralysis nor sensory impairment was observed. Head CT performed on day 3 after onset revealed a cortical infarction in the right prefrontal gyrus. Symptoms gradually improved with medical management. This patient had isolated facial and hypoglossal nerve paresis without other neurological symptoms. Patients with mild paresis of cranial nerves should be diagnosed carefully, because their paresis could be supranuclear type.