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At least 271 records · Page 15Linked to original sources
PubMed2003

[Apomorphine hyperpigmentation].

A 72 year old bedridden, disoriented man presented with a continuously increasing number of blue nodules on his abdomen and both thighs. In addition, he had a melanoma on his left forearm (SSM, Clark level III, Breslow 0.75 mm), which lead to the clinical diagnosis of melanoma metastases. Biopsy of one of the blue nodules showed CD68 positive histiocytic cells loaded with brownish pigment granules and a lymphocytic infiltrate within the deep dermis and upper subcutis. The pigment reacted histochemically similarly to melanin. Melanocytes were absent at these sites. Because of the unexplained clinical and histopathological picture, the patient's history was reassessed and it was learned that the patient had received subcutaneous infusions of apomorphine for the past 10 years for the treatment of Parkinson's disease. By oxidation, apomorphine may be converted into tetrahydroisoquinoline-melanin, which apparently is the cause for the accumulation of pigment within the deep dermis.

ADP-ribosyl Cyclase↗
PubMed1993

Histamine stimulates normal human melanocytes in vitro: one of the possible inducers of hyperpigmentation in urticaria pigmentosa.

Isolated normal human melanocytes became enlarged and more dendritic in association with an increase in the activity of tyrosinase and the amount of b-locus protein when they were cultured with 0.1-10 microM histamine in vitro. However, histamine did not exert a proliferative effect on them. The stimulatory effect of histamine was observable even 6 h after starting the treatment. This stimulation seems not to be pharmacologically mediated through histamine receptors, because it was inhibited neither by pyrilamine, a histamine H-1 antagonist, nor by cimetidine, a H-2 antagonist. Imidazole derivatives that are rapidly metabolized from histamine in vivo and in vitro also stimulated the melanocytes. We propose that high concentrations of histamine and its imidazole metabolites continuously produced in the lesions of urticaria pigmentosa are probable causative factors of its characteristic skin pigmentation.

Adult↗
PubMed2004

Linear hyperpigmentation with extensive epidermal apoptosis: a variant of linear lichen planus pigmentosus?

We report 3 female patients who rapidly developed pigmented patches in a linear arrangement. Histologically there was minimum epidermal basal cell damage and bandlike lymphocyte infiltration in the dermis, but focal massive apoptotic materials positively stained with antikeratin antibody were prominently seen in the papillary and subpapillary dermis. We considered these cases as a variant of linear lichen planus pigmentosus with unique histologic change of severe epidermal apoptosis. These histologic features may represent a severe apoptotic change in the end stage of lichenoid tissue reaction.

Adult↗