An intriguing 'cyst' of the ear.

A 35-year-old woman presented with a 2 cm left ear concha fluctuant swelling that had gradually increased in size over 2 months (figure 1). There were no lesions nor lymphadenopathy elsewhere. The initial clinical impression was an ear pseudocyst. The lesion was subsequently excised. Intraoperative findings were those of a cystic lesion with a thickened anterior wall. Fragments of the ‘cyst’ wall were sent for histological review. Review the high quality, interactive digital Aperio slide at http://virtualacp.com/JCPCases/jclinpath-2020-206475.R2.ndpi/ and consider your diagnosis. Figure 1 Clinical image of the ear swelling. 1. Lymphoproliferative disorder. 2. Lymphohistiocytic infiltrate, possibly infectious. 3. Metastatic melanoma. 4. Rosai-Dorfman disease (RDD). 5. Soft tissue neoplasm. The correct answer is after the discussion. RDD, also …