Bernard Letot

Histologic study of delayed reactions to coelenterates

We studied by immunohistochemistry three cases of delayed envenomation by coelenterates. The most prominent features were the grouping of human leukocyte antigen-DR-positive cells with Langerhans cells (S-100 positive) and helper/inducer T lymphocytes (Leu-1+, Leu-3+, and Leu-4+). This indicates the possibility of a type IV immunoreaction in the delayed cutaneous lesions caused by coelenterates.

Acute Reactions to Coelenterates

Many coelenterates can injure human skin by means of their nematocytes. Our study was based upon clinico-pathological confrontations and was also conducted in vitro with sea anemones. Most acute reactions were toxic in nature and induced sublethal and lethal alterations of the keratinocytes with swelling of their cytoplasms and pyknosis. Another reaction found in 1 patient revealed an acantholytic disruption of the epidermis associated with intercellular deposits of IgG. These lesions were different from the late or recurrent reactions to coelenterates.

Cyanoacrylate skin surface stripping: an improved approach for distinguishing dysplastic nevi from malignant melanomas

We present a novel approach for improving the management of patients with pigmented neoplasms including malignant melanomas and dysplastic nevi. A cohort of 215 dysplastic nevi and malignant melanomas was studied by cyanoacrylate skin surface stripping (CSSS) and conventional histology. Presence of atypical melanocytes was found in the stratum corneum in more than 95% of malignant melanomas and was always absent in dysplastic nevi. We conclude that this non‐invasive technique is rapid, easy to perform, and inexpensive. Its specificity and sensitivity are high enough to be considered by clinicians as an aid for distinguishing dysplastic nevi from malignant melanomas. We recommend this ancillary technique as a screening procedure though not as a substitute for conservative excisional biopsy, when doubt persists in the diagnosis of atypical pigmented neoplasms.

Chemical warfare casualties and Yperite-induced xerodermoid

Chemical warfare agents have been used in recent conflicts. We present a review of the clinical manifestations of mustard gas casualties and we studied the histological presentation of cutaneous lesions. Four groups of alterations were recognized, namely (a) alterations of keratinocytes, (b) epidermal hyperplasia with or without atypia, (c) alterations of the melanocytic system, and (d) structural changes of the dermis.