Poliosis circumscripta: overview and underlying causes.

Although traditionally known as "white forelock," poliosis circumscripta, defined as a localized patch of white hair in a group of hair follicles, can involve any hairy area on the body including the scalp, eyebrows, and eyelashes. Microscopically, poliosis demonstrates either decreased or absent melanin and/or melanocytes in the hair bulbs of the affected hair follicles. Classically, poliosis is known to occur in the setting of several genetic syndromes including piebaldism, Waardenburg, and tuberous sclerosis. In addition, poliosis has been described in association with various acquired conditions. These include inflammatory conditions, benign and malignant neoplastic entities that are mainly melanocytic, medications, and others. In this review, we aim to describe the different conditions where poliosis may be encountered, with the aim of helping the clinician to better evaluate any patient presenting with poliosis.

Anomalous colour in Neotropical mammals: a review with new records for Didelphis sp. (Didelphidae, Didelphimorphia) and Arctocephalus australis (Otariidae, Carnivora).

Anomalous colourations occur in many tropical vertebrates. However, they are considered rare in wild populations, with very few records for the majority of animal taxa. We report two new cases of anomalous colouration in mammals. Additionally, we compiled all published cases about anomalous pigmentation registered in Neotropical mammals, throughout a comprehensive review of peer reviewed articles between 1950 and 2010. Every record was classified as albinism, leucism, piebaldism or eventually as undetermined pigmentation. As results, we report the new record of a leucistic specimen of opossum (Didelphis sp.) in southern Brazil, as well as a specimen of South American fur seal (Arctocephalus australis) with piebaldism in Uruguay. We also found 31 scientific articles resulting in 23 records of albinism, 12 of leucism, 71 of piebaldism and 92 records classified as undetermined pigmentation. Anomalous colouration is apparently rare in small terrestrial mammals, but it is much more common in cetaceans and michrochiropterans. Out of these 198 records, 149 occurred in cetaceans and 30 in bats. The results related to cetaceans suggest that males and females with anomolous pigmentation are reproductively successful and as a consequence their frequencies are becoming higher in natural populations. In bats, this result can be related to the fact these animals orient themselves primarily through echolocation, and their refuges provide protection against light and predation. It is possible that anomalous colouration occurs more frequently in other Neotropical mammal orders, which were not formally reported. Therefore, we encourage researchers to publish these events in order to better understand this phenomenon that has a significant influence on animal survival.

Anomalous colour in Neotropical mammals: a review with new records for Didelphis sp. (Didelphidae, Didelphimorphia) and Arctocephalus australis (Otariidae, Carnivora) / Coloração anômala em mamíferos Neotropicais: uma revisão com novos registros para Didelphis sp. (Didelphidae, Didelphimorphia) e Arctocephalus australis (Otariidae, Carnivora)

Anomalous colourations occur in many tropical vertebrates. However, they are considered rare in wild populations, with very few records for the majority of animal taxa. We report two new cases of anomalous colouration in mammals. Additionally, we compiled all published cases about anomalous pigmentation registered in Neotropical mammals, throughout a comprehensive review of peer reviewed articles between 1950 and 2010. Every record was classified as albinism, leucism, piebaldism or eventually as undetermined pigmentation. As results, we report the new record of a leucistic specimen of opossum (Didelphis sp.) in southern Brazil, as well as a specimen of South American fur seal (Arctocephalus australis) with piebaldism in Uruguay. We also found 31 scientific articles resulting in 23 records of albinism, 12 of leucism, 71 of piebaldism and 92 records classified as undetermined pigmentation. Anomalous colouration is apparently rare in small terrestrial mammals, but it is much more common in cetaceans and michrochiropterans. Out of these 198 records, 149 occurred in cetaceans and 30 in bats. The results related to cetaceans suggest that males and females with anomolous pigmentation are reproductively successful and as a consequence their frequencies are becoming higher in natural populations. In bats, this result can be related to the fact these animals orient themselves primarily through echolocation, and their refuges provide protection against light and predation. It is possible that anomalous colouration occurs more frequently in other Neotropical mammal orders, which were not formally reported. Therefore, we encourage researchers to publish these events in order to better understand this phenomenon that has a significant influence on animal survival.

Colorações anômalas ocorrem em muitos vertebrados tropicais. Entretanto, estas são consideradas raras em populações selvagens, havendo poucos registros para a maioria dos táxons. Reportam-se, neste estudo, dois novos casos de coloração anômala em mamíferos. Além disso, por meio de uma extensa revisão bibliográfica, foram compilados os casos publicados sobre coloração anômala em mamíferos neotropicais entre 1950 e 2010. Cada registro foi classificado como albinismo, leucismo, piebaldismo ou, eventualmente, como coloração indeterminada. Como resultados, reportou-se o registro de um espécime leucístico de gambá (Didelphis sp.) no sul do Brasil e de um espécime de lobo-marinho sul-americano (Arctocephalus australis) com piebaldismo no norte do Uruguai. Também foram analisados 31 artigos científicos, resultando em 23 registros de albinismo, 12 de leucismo, 71 de piebaldismo e 92 registros classificados como de pigmentação indeterminada. A coloração anômala aparentemente é rara em pequenos mamíferos terrestres, mas é muito mais comum em cetáceos e microquirópteros. Dos 198 registros encontrados, 149 ocorreram em cetáceos e 30 em morcegos. No caso dos cetáceos, este resultado sugere que machos e fêmeas com este padrão anômalo de pigmentação são reprodutivamente exitosos e, consequentemente, sua frequência está aumentando nas populações naturais. Com relação aos morcegos, este fenômeno pode estar relacionado ao fato de estes animais orientarem-se primariamente por meio de ecolocalização e seus refúgios oferecerem proteção contra luz e predação. É possível que a coloração anômala ocorra mais frequentemente em outras ordens de mamíferos neotropicais, as quais não foram formalmente reportadas. Desta forma, mostra-se importante encorajar os pesquisadores a publicar estes eventos em vida selvagem para um melhor entendimento deste fenômeno, que tem influência significativa na sobrevivência destes organismos.

Cutaneous cancers in Calabar, Southern Nigeria.

Globally, cutaneous cancers are among the most common form of cancer. Among Africans, there are significant differences in the types of skin cancer compared to those documented in patients from other countries. We evaluated all the patients with a histological diagnosis of skin cancer presenting to the University of Calabar Teaching Hospital from January 2005 through December 2006. Twenty-nine patients (18 males and 11 females) with skin cancer were identified and these accounted for 8.0 percent of total malignancies. Their ages ranged from 16 to 70 years (mean 43.5 years). Kaposi sarcoma (KS) was the most common skin cancer. Kaposi sarcoma associated with HIV represented 81.8 percent of KS cases found. Squamous cell carcinoma (SCC) ranked second and malignant melanoma third. Of the skin cancers in our series, the most common site was the lower limb (55.2%), followed by the head and neck (24%). The 4 albinos accounted for 13.8 percent of the skin cancers found. Immunosuppression (KS), chronic ulcer, inflammation, albinism, and solar radiation were identified risk factors. Public education strategies on prevention, with an emphasis on early identification and surgical treatment of skin cancers are urged. In addition, treatment of and close observation of chronic ulcers are recommended.