Background: In 1952, Zoon described a series of patients with dense plasma-cell infiltrates in the glans penis. Since then, similar Zoon-like lesions (ZLL) have been described on the external female genitalia and in the airways, for which over 20 designations currently exist. Methods: Twenty-eight cases of ZLL, twenty-two cases of lichen planus, eight cases of plasmacytoma and two cases of syphilis were evaluated from the surgical pathology archive at the University of Virginia. Twenty-four histologic data points were tabulated in each case, including 12 epidermal and 12 dermal features. Results: Histopathologic findings were similar in the majority of cases of ZLL, regardless of their location. They demonstrated superficial cutaneous erosions, basal vacuolar alteration and many showed lozenge-shaped keratinocytes in the epiderms. The dermis contained a dense inflammatory infiltrate composed predominantly of plasma cells, with scattered neutrophils and lymphocytes. Dense fibrosis was seen in the upper dermis. Conclusions: A uniform nomenclature for ZLL does not exist. Based on the results of this analysis, we suggest that the generic term idiopathic lymphoplasmacellular mucositis-dermatitis be considered to encompass the lymphoplasmacellular infiltrates in the skin and mucosal surfaces considered herein. This designation is morphologically descriptive and can be applied regardless of anatomic location.