Scanning electron microscopy of tinea nigra

Tinea nigra is a rare superficial mycosis caused by Hortaea werneckii. This infection presents as asymptomatic brown to black maculae mostly in palmo-plantar regions. We performed scanning electron microscopy of a superficial shaving of a tinea nigra lesion. The examination of the outer surface of the sample showed the epidermis with corneocytes and hyphae and elimination of fungal filaments. The inner surface of the sample showed important aggregation of hyphae among keratinocytes, which formed small fungal colonies. The ultrastructural findings correlated with those of dermoscopic examination - the small fungal aggregations may be the dark spicules seen on dermoscopy - and also allowed to document the mode of dissemination of tinea nigra, showing how hyphae are eliminated on the surface of the lesion.

Scanning electron microscopy of acantholysis in pemphigus foliaceus / Microscopia eletrônica de varredura da acantólise no pênfigo foliáceo

We performed scanning electron microscopy of an inverted blister roof in a case of pemphigus foliaceus. The loss of intercellular adherence could be easily seen with low magnification. The acantholytic keratinocytes displayed an irregular and sometimes polygonal contour. Round cells, typically seen in light microscopy, were also observed. The examination of a blister roof allows ultrastructural documentation of the acantholytic changes.

Realizamos microscopia eletrônica de varredura do teto invertido de uma bolha de um caso de pênfigo foliáceo. Com pequeno aumento, a perda da adesão intercelular pôde ser vista claramente. Os queratinócitos acantolíticos demostraram um contorno irregular, algumas vezes poligonal. Células arredondadas, como vistas tipicamente na microscopia óptica, também foram observadas. O exame de um teto de bolha permite uma documentação ultraestrutural das alterações acantolíticas.