Amorphous basophilic deposit in the superficial dermis of the lip in an 80 year old.

An 80-year-old woman presented with a 3 mm pearly, translucent papule in her left upper cutaneous lip of 2 months duration which was biopsied to rule out basal cell carcinoma. Histopathologic examination revealed acellular, basophilic material in the superficial dermis, extending to the base of the biopsy. There was neither an epithelial component nor an inflammatory reaction associated with it. The amorphous, nonpolarizable material stained with Alcian Blue (pH 2.5) and with colloidal iron, but was negative with a Periodic acid-Schiff stain, indicative of an acidic mucin, such as weakly sulfated mucin of salivary gland origin or a dermal-origin mucin. The material was digested with hyaluronidase, consistent with the mesenchymal-origin mucin hyaluronic acid (HA). Additional clinical history was obtained; the patient had previous HA (Restylane) injections at another institution. We report a case of superficially applied HA and consider the histopathologic differential diagnosis of endogenous and injected mucin in the dermis.