Diffuse Pigmentation Research Articles

Radiographic and Histological Appearances of the Rat Lung after Intratracheal Injection of Rouge (Fe2O3)

The first published suggestion that some shadows in radiographs of lungs might be produced by iron oxide and not by fibrosis was made by Collis in 1923, but Fawcitt (1943) quotes letters exchanged between Thurston Holland and Collis in 1919 when the possibility was discussed. In 1936 Doig and McLaughlin gave the first account of the x-ray appearances of the lungs of electric-arc welders, and suggested that these appearances might be due to iron deposits. Recently McLaughlin, Barrie, Grout and Harding (1945) have reported on the condition of the lungs of silver polishers, suggesting that these workmen have no industrial disability and that the radiographie abnormalities in their lungs are the result of iron oxide deposition without attendant fibrosis. A brief review of the literature of iron pigmentation of the lung is also given. Since this last paper was written, the lungs of two more silver polishers have been examined and found to show similar pigmentation without fibrosis. Since then the Miners' Phthisis Bureau of South Africa (1944) report investigations on a native iron-ore miner whose radiograph at the end of 1937 showed a ' generalized small mottling throughout the fields of both lungs ' ; this man died from lobar pneumonia in 1939, and his lungs were found to have heavy deposits of haematite dust but no fibrosis. The report concludes that the ' mottling observed in his radiograph was due entirely to deposits of haematite in the lung substance and not to fibrosis.' There are few papers describing the effects of iron oxide on the lungs of experimental animals, and no reports of the production of radiographie appearances corresponding with the reticulation or nodulation found in man. There is, however, general agreement that iron oxide does not produce fibrosis under the varied experimental conditions used. It is not proposed to discuss here the early histological picture, which is well described in the guinea-pig by Carleton (1927) and by Haynes (1931). Naeslung (1937, 1938) used a number of dusts, mainly derived from iron ores, in inhalation experi ments on rabbits, and found fibrosis in the lungs of only those animals which had inhaled a silica containing dust. He pictured the miliary accumu lations of iron pigment, and noted that ' a number of animals amongst which pneumoconiosis or silicosis was obvious on autopsy had shown no alterations of the lungs when x-rayed at the conclu sion of the dust exposure.' In a further experiment (Naeslund 1940), two rabbits inhaled a mixture of Fe203 and Fe205 for six months; when they were killed three months later the lungs are stated to have shown a slight general fibrotic change but no nodular fibrosis. Harrold, Meek and McCord (1940) exposed rabbits and rats to welding fumes; th y noted that early diffuse pigmentation became more nodular with time, and that ' no fibrotic c anges or other pathology of a permanent nature ascribable to metallic fumes have been observed/ They also said that ' x-ray examinations made on intact animals and on extirpated lungs yielded no positive results.' Gardner and McCrum (1942) studied x-ray films of the distended lungs of 3 cavies exposed to arc-welding fumes for 10 months and then kept in a normal atmosphere for another 3 months. No pictures were given but they stated ' to our surprise it was possible to distinguish their films from that of a normal animal's lungs. The great number of fine particles of high molecular weight cast a diffuse shadow which gave the lung fi lds a very fine grainy appearance.' They found that the response to the metallic particles in the fume was that to inert foreign particles : ' it con sisted of simple phagocytosis without demonstrable ef ect upon the dust cells and without subsequent proliferation of fixed tissues.' I agree with this statement.

PRECANCEROUS MELANOSIS AND DIFFUSE MALIGNANT MELANOMA OF THE CONJUNCTIVA

The fact that tissue may undergo certain changes prior to the development of a malignant growth is well known. A precancerous stage of varying duration has been observed in the experimental production of epithelioma in animals. In human beings such instances are afforded by the senile dystrophy of the skin which manifests itself by atrophy, degeneration of elastic tissue, flecks of pigment, telangiectasis and circumscribed keratosis. The same changes are seen in xeroderma pigmentosum. Other conditions in which such changes occur are leukoplakia, extramammary Paget's disease and Bowen's disease. Among these rarer manifestations can be mentioned also melanosis of the skin and of the conjunctiva. In dermatology this is recognized as a precancerous change, and considerable is known about its clinical and histologic characteristics. It may appear in the skin anywhere over the body but has a predilection for the face. It is a rather diffuse nonelevated pigmentation

Reaction of Osseous Tissues to Pressure under Partial Restorations

Oral pigmentation is a common finding in the mouth. Pigmentation can be either normal or abnormal discoloration of oral mucous membrane. The purpose of this review mainly focuses on the main oral pigmented lesions, in order to help the clinicians establish a better approach towards the patients with pigmented oral lesions and to provide thorough knowledge regarding such lesions for patient reassurance, early definitive diagnosis and prompt treatment.Relevant data concerning oral pigmented lesions, clinical features and the possibility of malignant transformation of such lesions were reviewed thoroughly from pubmed literature published in English. Pigmented lesions affecting the skin were not included in our review.Few pigmented lesions have been identified and their tendency to become malignant has been reported in the literature. The oral lesions showing malignant transformation reported were mostly case series. Unfortunately, due to lack of long-term studies, follow ups and randomized controlled studies in this respect it was difficult to draw a statistical analysis. This information is quite crucial for general dental practitioners to improve their understanding regarding oral lesions and to differentiate between normal and diseased conditions, so that they can master the skill of differential diagnosis, definitive diagnosis and prompt treatment.Oral pigmentation may present as focal, multifocal or diffused macular or tumefactive lesions. They may greatly vary in color as blue, purple, brown, gray or black depending on the quantity and site of melanin in the tissues [1]. Etiology of pigmentation can be multi factorial. Mostly pigmentation is physiologic but at times it can be a precursor of severe diseases.Lesions may be caused by localized harmless accumulations of melanin, hemosiderin or exogenous metals or they may be a sign of underlying systemic or genetic disease. A few lesions may be associated with life-threatening medical conditions that require immediate intervention. The differential diagnosis for any pigmented lesion is extensive, as it includes examples of endogenous and exogenous pigmentations. Although biopsy is a helpful and necessary aid in the diagnosis of focally pigmented lesions, with diffuse pigmentation lesions require a thorough dental and medical history and laboratory investigations.

THE PATHOLOGY OF MELANOSIS AND OF BENIGN MELANOMAS OF THE CILIARY BODY

Benign melanomas of the ciliary body are rarely found, and then usually accidentally during the routine examination of serial sections. The pathologic diagnosis can at times be difficult. One should differentiate the circumscribed, sharply defined, pigmented, tumor-like area that can be called a pigmented nevus or benign melanoma from the diffuse pigmentation present in association with general ocular melanoses and from those local diffuse pigmentations, sometimes in the form of streaks, that one often finds normally in the ciliary body of eyes otherwise not excessively pigmented. Normally, the ciliary body contains some pigmented cells in its stroma. The degree of pigmentation depends not only on the number of pigmented cells present, but on the amount of pigment granules present in these cells and the color of the granules themselves. These vary with age, sex and type. Brunettes, as a rule, possess pigmented cells containing relatively more and darker

ERYTHROSE PERIBUCCALE PIGMENTAIRE DE BROCQ

We have had under our observation for some time a small group of patients with a type of peribuccal pigmentation sufficiently different from the usual disorders of this area and of a sufficiently uniform character to warrant consideration as a distinct clinical entity. A review of the literature convinced us that the disorder in question is identical with that described by Brocq 1 in 1923 as erythrose peribuccale pigmentaire, so we adopted his title. Our patients were all women in the thirties or early forties. The condition absorbed a disproportionate amount of their attention on account of the cosmetic disfigurement and the extraordinary resistance to treatment. It was observed only in private patients, and we found it impossible to secure a biopsy from this region of the face. Consequently, our study is purely clinical, unsupported by histologic evidence. The disorder consists of a diffuse brownish or brownish-red pigmentation, most marked

Diffuse pigmentation of the epidermis of the oyster due to prolonged exposure to the light: Regeneration of shell and loss of adductor muscle

Diffuse pigmentation of the epidermis of the oyster due to prolonged exposure to the light: Regeneration of shell and loss of adductor muscle