Immunohistochemical evaluation of tenascin in benign eccrine gland tumors: comparison with laminin and fibronectin

Evaluation of the expression of P-selectin, ICAM-1, and TNF-alpha in bacteria-free lesional skin of atopic dogs with low-to-mild inflammation

Canine atopic dermatitis (AD) is a pruritic skin condition that shares many clinical and pathophysiological features with its human counterpart. A major therapeutic challenge of AD is the control of the skin inflammatory process. A detailed knowledge of the pro-inflammatory molecules involved in cell recruitment in AD would allow for a better control of the disease. We thus have studied the protein expression of P-selectin, ICAM-1 and TNF-alpha in the lesional and non-lesional skin of atopic dogs that had been treated for bacterial infections. Despite a low-to-mild inflammatory process, P-selectin protein was clearly upregulated in the lesional skin areas when compared with non-lesional skin (four-fold average increase). This P-selectin upregulation was accompanied by signs of functional changes such as increased cell margination, and membrane-associated protein expression. Although the expression of ICAM-1 and TNF-alpha was not enhanced in the lesional versus the non-lesional skin, there was a trend towards a correlated upregulation of both molecules. Further studies will help elucidate the significance of the substantial overexpression of P-selectin in canine AD, in particular in a scenario where bacterial antigens are not contributing as pro-inflammatory stimuli.

Desmoplastic seborrheic keratosis

Eleven cases of seborrheic keratoses with desmoplastic stroma and associated nests and cords of squamous epithelium simulating infiltrating carcinoma are presented. There were 7 males and 4 females ranging in age from 44 to 88 years (mean = 62). Eight cases were on the head and neck, one each on the lower and upper extremity, and one on the pubic area. Clinical diagnoses included seborrheic keratosis, squamous and basal cell carcinoma, and dermal nevus. Histologically, the lesions were characterized by exophytic growth pattern of basaloid and squamous cells, without cytologic atypia, and well-demarcated peripheral borders, typical for that seen in seborrheic keratoses. Squamous eddy formation with parakeratosis and spongiosis was present in all cases. Located within the body of the lesions were irregular nests and cords of squamous cells extending into the surrounding dermis with associated fibroblastic dermal proliferation trapping the epithelial nests, simulating invasive carcinoma. Immunohistochemically, the epithelial nests were cytokeratin positive and HPV negative, and the dermal stromal cells were vimentin positive and factor XIIIa, cytokeratin, and CD34 negative. Adjacent changes of carcinoma, trichilemmoma, verruca, or other adnexal neoplasm were not identified. Seborrheic keratoses may demonstrate desmoplastic changes analogous to that seen in desmoplastic trichilemmomas. Awareness of these changes in seborrheic keratosis will avoid misdiagnosis and excessive therapy.