Abstract Acral persistent papular mucinosis (APPM) is a rare subtype of localized lichen myxedematosus. It consists of small papules localized exclusively on the back of the hands, wrists and extensor aspects of distal forearms with no other clinical or laboratory manifestations. The lesions tend to persist and may increase slowly in number. Histologically, hematoxylin-eosin and Alcian blue staining demonstrate mucin accumulation in the upper reticular dermis with separation of collagen fibers as a result of hyaluronic acid deposition. Treatment is rarely necessary due to the absence of symptoms. We present a 27-year-old healthy woman with asymptomatic papules on her upper extremities, which adequately meet clinical and pathological criteria of acral papular mucinosis.

En la última revisión de la Organización Mundial de la Salud (OMS) en relación a los tumores del sistema nervioso central (SNC), se describieron nuevas entidades, como el Tumor Papilar de la Glándula Pineal. Esta lesión de rara aparición, se ha identificado en adultos jóvenes. El diagnóstico de estos tumores es complejo ya que depende de su ubicación, edad de aparición y el aspecto histológico; éste último tiene similitudes con otras lesiones como el ependimoma papilar o el papiloma/carcinoma de plexos coroides. Citológicamente presentan características claras que pueden ayudar al diagnóstico a través de la impronta en el estudio intraoperatorio; reconocer ciertos criterios con éste importante y sencillo método diagnóstico ha sido la motivación principal para el estudio de entidades poco frecuentes del SNC, además de corroborar el necesario trabajo de un equipo multidisciplinar.

In the latest revision of the central nervous system tumors (CNS) of the World Health Organization (WHO), new entities has been described, as papillary tumor of the pineal region. This rare lesion has been identified in young adults. The diagnosis of these tumors is complex, depends on the location, age of onset and histological appearance. Histological characteristics have similarities with other lesions such as papillary ependymoma, papiloma / choroid plexus carcinoma. Cytologically have clear characteristics that can aid in the diagnosis through the smears on the intraoperative study. Certain criteria for recognize this important and simple diagnostic method has been the main motivation for the study of CNS rare entities, as our case, in addition to corroborating the necessary work of a multidisciplinary team.