An ultrastructural study of a juvenile melanoma.

An unusual variant of juvenile melanoma, namely a sclerosing juvenile melanoma occurring on the buttock, has been studied by light and electron microscopy. The diagnosis of a pigment tumour was confirmed by the presence of structures common to these lesions, i.e. melanosomes, intracytoplasmic fibrils and microvilli on the cell surface. The tumour consisted of two cell configurations, namely a multinucleated giant cell and a second cell made up of two separate cells lying in close apposition, the cytoplasm of one cell being dark and the other light. This tumour can be differentiated from a benign naevus by the bizarre histological appearance on light microscopy. On electron microscopy the distinction is made by the presence of the very large multinucleated giant cells, the apposition of the light and dark cells, the scanty melanosomes and the presence of intracytoplasmic lumina. The value of electron microscopy in the determination of the nature of unusual skin tumours is discussed.

Malacoplakia associated with transitional cell carcinoma of bladder.

Malacoplakia is an uncommon granulomatous condition, usually involving the bladder but occasionally affecting other organs. A case of malacoplakia associated with transitional cell papillary carcinoma of the bladder is reported. This association has not been documented previously.

Tumours of accessory parotid glands. Case reports.

Tumours arising in accessory parotid glands are a distinct entity and a pitfall for the unwary . The diagnosis is made on the basis of clinical examination and a high index of suspicion is essential. Treatment is by wide exposure and careful dissection because of the relationship of the accessory parotid gland to the facial nerve and parotid duct. Four cases are described.

The treatment of giant hairy naevi by dermabrasion in the first few weeks of life. Case reports.

A method for treating congenital giant naevi in the first few weeks of life by mechanical dermabrasion is described. From reports in the literature and from our 2 cases it would seem that this is a very effective method for removing pigmentation early in life. The cosmetic deformity of these lesions is eradicated and their malignant potential possibly minimized.

Mechanisms of thrombocytopenia in malignant tertian malaria.

The mechanism of thrombocytopenia in six patients with falciparum malaria has been studied. All the patients recovered after antimalarial therapy, and cerebral malaria was not a feature. Radioactive-labelled platelets and fibrinogen were injected into the patients during the phase of thrombocytopenia. In all cases recovery of injected platelets was notably subnormal, indicating excessive splenic pooling of platelets. Platelet life span was moderately shortened in all patients, and platelet turnover increased approximately two-fold. Fibrinogen catabolism was moderately increased in all patients, but coagulation tests failed to reveal evidence of disseminated intravascular coagulation. The results suggest that in uncomplicated cases of malaria thrombocytopenia is the result of splenic pooling of platelets aggravated by a moderate decrease in platelet life span. In such cases thrombocytopenia is thus not the result of disseminated intravascular coagulation (D.I.C.), and heparin therapy is not indicated unless there is unequivocal ancillary evidence of D.I.C.

Clinical and molecular features of the hereditary mixed polyposis syndrome.

BACKGROUND & AIMS: Various inherited syndromes predispose to the development of colonic juvenile polyps and colorectal cancer, with potential importance for sporadic tumorigenesis. This study describes features of a possibly new syndrome of atypical juvenile polyps and other colonic tumors and compares these features with those of known gastrointestinal tumor syndromes. METHODS: A large family, St. Mark's family 96, with a tendency to develop colonic polyps of mixed histological types is described. Genetic linkage to known polyposis syndromes has been tested. RESULTS: Adenomatous and hyperplastic polyps occur in affected members of the family, although the characteristic lesion is an atypical juvenile polyp. Some affected individuals have developed polyps of more than one type, and individual polyps may contain features of more than one histological type. Polyps can undergo malignant change. Typically, fewer than 15 polyps are found at colonoscopy and there is no extracolonic disease associated with the development of polyps. The family's polyps seem to be inherited in an autosomal-dominant fashion, but the disease is probably unlinked to candidate loci with importance in colorectal tumorigenesis, such as APC, hMSH2, and hMLH1. CONCLUSIONS: We term this family's disease hereditary mixed polyposis syndrome (HMPS). Although mutations in the putative HMPS gene may be responsible for syndromes such as juvenile and Peutz-Jeghers polyposes, HMPS may also be a distinct disease.