Parameters related to oxygen free radicals in human skin: a study comparing healthy epidermis and skin cancer tissue.

In vitro studies with tumor cells have demonstrated that oxygen free radicals are involved in the development of skin cancers and that variations in the body's defense mechanisms can modify the course of the disease. To assess the validity of this hypothesis in spontaneous tumors, we determined glutathione S-transferase, superoxide dismutase, reduced and oxidized glutathione, and thiobarbituric acid reactive substances in healthy whole skin (n = 95), dermis (n = 73), and epidermis (n = 69). The values were compared with those obtained in three types of skin cancer: basal cell carcinoma (n = 16), squamous cell carcinoma (n = 6), and melanoma (n = 33). In healthy skin, glutathione S-transferase, superoxide dismutase, reduced glutathione, and oxidized glutathione were higher in epidermis than in dermis, whereas thiobarbituric acid reactive substances were higher in dermis than in epidermis; whole skin had intermediate values. These results suggest that there is an induction of some anti-oxygen free radicals mechanisms in epidermis as a result of increased oxygen free radicals production. Glutathione S-transferase and thiobarbituric acid reactive substances were higher in all types of tumor than in healthy epidermis but oxidized glutathione was lower. Reduced glutathione and superoxide dismutase activity were lower in basal cell carcinoma and squamous cell carcinoma samples. Glutathione S-transferase increased, whereas superoxide dismutase and thiobarbituric acid reactive substances decreased in melanoma samples in direct relation to the Clark levels. Higher glutathione S-transferase activity, particularly in the most invasive forms of melanoma, indicates that this type of cancer is more malignant. Similarly, a decrease in superoxide dismutase activity can also encourage progression of the tumor. These results are in accord with those from tumor cell cultures and could suggest new strategies (gene therapy) for managing skin cancer.

Circumscribed palmar or plantar hypokeratosis: a distinctive epidermal malformation of the palms or soles.

BACKGROUND: Epidermal malformations of the skin include a group of heterogeneous developmental defects that result from errors in morphogenesis of the epidermis during intrauterine life. OBJECTIVE: The purpose of this study was to report the clinical and histopathologic features of a distinctive epidermal malformation involving the skin of the palms or soles. METHODS: Ten patients were included in this study. All of them showed the same clinical features that consisted of a solitary circumscribed and circular area of erythematous depressed skin on the palm or on the sole. Diagnosis was confirmed by histopathologic study. RESULTS: All patients were middle aged or elderly. Nine patients were women and one was a man. The lesions showed predilection for the skin of the thenar and hypothenar regions of the palm or the medial side of the sole. Histopathologic study demonstrated a depression of the epidermis, with a sharp stair between normal and involved skin. The epidermis covering the depression showed markedly thinner horny layer and a slightly diminished granular cell layer when compared with adjacent noninvolved skin. Keratinocytes of the squamous cell layer, granular cells, and corneocytes showed, otherwise, a normal appearance. Serial sections failed to demonstrate cornoid lamellation. CONCLUSION: On the basis of the clinical and histopathologic findings in these 10 patients, we have named this malformation circumscribed palmar or plantar hypokeratosis. This lesion seems to be a distinctive entity that has not been previously described.

Metameric motor paresis following abdominal herpes zoster.

Motor neuropathy is an uncommon complication that may follow an outbreak of herpes zoster (HZ). About half of the reported cases have involved the cranial nerves, typically the facial nerve. The remaining cases have affected the nerves of the extremities. Interestingly, motor weakness of the thoracic segments is strikingly rare, even though this is where HZ most frequently occurs. The dermatologic literature reports only exceptions to this occurence. We report a new case of motor paresis following HZ infection in an abdominal location, where this complication can be easily misdiagnosed as abdominal herniation.