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A histopathological study of mucocutaneous leishmaniasis due to Leishmania (Viannia) braziliensis was carried out on 28 cutaneous and 114 mucosal biopsies, taken from Bolivian and Peruvian patients. This study showed similar histopathological findings in cutaneous and mucosal lesions. The cutaneous biopsies showed a strong epidermal hyperplasia occasionnally budding in the dermis. In the ulcerative area, the epidermis was totally necrosed and replaced by a fibrino-leucocytic edge. In the dermis, histio-lympho-plasmocytic infiltration was constantly found. The histiocytes often gathered in follicles sometimes with diffuse fibrosis. The parasites were encountered in 28.6 p. 100 of the biopsies. Whatever the mucosa concerned (i.e. nasal, palatal or lingual), the mucosal lesion was not different from the cutaneous lesion. The malpighian epithelium is either absent or the seat of a pseudo-epitheliomatous hyperplasia. Major histio-lympho-plasmocytic infiltration was found and extended through the depth of the lamina propria. Suppurative and fibrinoid necroses coexisted superficially and sometimes penetrated in depth. The parasites were found in about 30 p. 100 of the cases.

The Cancer Registries have been operational in the South Pacific since 1958 (Papua New Guinea), Fiji (1965) and New Caledonia (1977) and complete cancer incidence rates are available, based on histologic data. We studied 97 melanomas, histologically confirmed, which were diagnosed in New Caledonia from 1973 to 1991. New Caledonia is located in the same latitude as Queensland in Australia, known for having the highest incidence of melanoma in the world. Standardised incidence rates (world population) were 9.82 and 7.65/100,000/year for European males and females, compared to 1.65 and 1.05 for Melanesian and Polynesian males and females. The European population is exposed and Melanesians/Polynesians are relatively protected as are black Americans or Africans. The mixed populations are protected, but no study is available as to the exact proportion of mixed people (20%?) in the entire population. For Europeans, among males, the main areas in which melanomas occur are the trunk (45%) the arm (13%) and the leg (13%). Among females, the main areas are the leg (27%), the trunk (20%) and the head (18%). Screening for melanoma has been more effective in the last 6 years, a period in which we diagnosed half the total cases and generally at earlier stages. Prognosis was poor for this period (1973-1991): the five year survival rates were 64% +/- 8%, not as good as in Europe or Australia, but these lesions were diagnosed between 1973 and 1985 and were generally more invasive. A better prognosis will probably be observed in a few years, and another evaluation of melanoma screening should be made in the future as well the study of precursors and early lesions.

Protothecosis are uncommon infections caused by Prototheca, considered to be achlorophylous algae. Nearly 80 human cases are reported in the literature since the first case described by Davies and Wakelin in 1964 in Sierra Leone (11). The disease have been identified in Europe, Asia (Japan, Thailand, China), Oceania and in the United States with 40 cases, particularly in the Southeast. Clinically, three clinical manifestations can be observed: 1) cutaneous lesions: papules, plaques or eczematoid, papulo-nodular areas of the extremities, 2) olecranon bursitis which occurred in 25% of cases, 3) systemic protothecosis. An immunosuppressive factor local or general can be found in half of the cases and the first description of algal meningitis was reported in a patient with AIDS in association with Cryptococcus neoformans. Because the disease is clinically not suspected, the diagnosis is often provided by histology showing a dermic granuloma with endospores. The characteristic feature of protothecosis in tissues is the presence of specific mature sporangia of Prototheca wickerhamii with the pattern of morula. The organism was PAS, Grocott and mucicarmin positive. The ecology was studied by Clark (7), Pidoux (23), Pore (25) and Sudman (27). Prototheca are ubiquitous inhabitants of sewages and are found in slime flux and animal wastes contaminating different aquatic systems. The transmission generally occurred by traumatic inoculation. Prototheca are also found in the digestive system of man and animals without never invasion of the epithelium and mucosae in experimental models. The pathogenicity and virulence are moderate and they are considered as rare opportunistic agents.