The spectrum of histopathologic patterns secondary to the topical application of EMLA® on vulvar epithelium: clinicopathological correlation in three cases.

EMLA(®) (eutectic mixture of local anesthetics, 2.5% each of lidocaine and prilocaine in an oil and water emulsion) is used as a topical anesthetic. We report three cases of EMLA(®) -induced histopathologic changes on the vulvar epithelium. While there are some similar histopathologic features to those reported in extragenital skin, we describe additional findings on vulvar epithelium, which, to our knowledge, have not been reported previously. The patients presented with clinical signs suggestive of lichen sclerosus or erosive lichen planus (LP), but were all confirmed histopathologically as LP. The biopsy was taken after 15 min of EMLA(®) application and intradermal injection of 1% lidocaine. Blistering prior to intradermal lidocaine and the biopsy procedure was observed in two patients. The histopathologic changes observed in the epithelium included pallor of the upper epidermis, mild spongiosis, intraepidermal subcorneal and suprabasal acantholysis, congestion of the papillary dermal capillaries and extravasated erythrocytes. Basophilic granules were present, but rare, while the necrosis with multifocal clefting was more marked than in extragenital skin. It is important to be aware of these changes occurring on genital mucosa; these may occur in the absence of clinical signs and may obscure the primary underlying pathology, thus representing a diagnostic pitfall.

The histopathologic spectrum of regression in atypical fibroxanthoma.

BACKGROUND: Atypical fibroxanthoma (AFX) with prominent fibrosis, sclerosis and hyalinization, and near-total tumor regression is rare. METHODS: Eight cases of AFX presenting with fibrosis were reviewed as to their tumor architecture, the degree and pattern of fibrosis and the associated inflammatory cell infiltrate. RESULTS: Seven of eight cases had an exophytic architecture, with ulceration in one case. The degree of fibrosis ranged from 10% to 90%. Early fibrosis (2/8 cases) occurred as thickened sclerotic collagen bundles, either dispersed between the neoplastic cells or as septa imparting a multilobular appearance. Advanced fibrosis (6/8 cases) was associated with lamellar sclerosis, keloidal features, hyalinization and with near-total tumor replacement. Prominent fibrosis rimming the periphery was present in all tumors. An associated lymphoid cell infiltrate with plasma cells and occasionally eosinophils was observed. CONCLUSIONS: Fibrosis with prominent sclerosis and hyalinization replacing the tumor is rare in AFX. Advanced fibrosis, in the absence of a history of prior trauma or surgery, may indicate spontaneous regression. These cases emphasize the importance of recognizing this subset of AFX in order to avoid misinterpretation, particularly in cases with few residual atypical cells.

Squamomelanocytic tumor: an unusual and distinctive entity of uncertain biological potential.

We report a case of a squamomelanocytic tumor of the skin. Clinically, the lesion was felt to be a melanocytic or vascular tumor but histologically was characterized by epithelioid cells with focal squamous differentiation. Immunohistochemical staining showed that half of cells stained with MNF116 and a smaller proportion stained with S100 and Melan A. A third population did not stain with either set of antigens. The lesion has some similarities to a melanocytic matricoma but no evidence of matrical differentiation. The biological potential of this distinctive tumor is not known because so few have been reported.