A Stab in the Back: An Unusual Case of Cutaneous Neural Infiltration as a Manifestation of Chronic Lymphoproliferative Disorder of Natural Killer Cells

Abstract: Chronic lymphoproliferative disorder of natural killer cells (CLPDNK) is a rare heterogenous indolent disorder comprising a persistent peripheral blood cell count of more than ≥2 × 109/L natural killer cells for over 6 months. We report an unusual case of cutaneous neural infiltration as a manifestation of CLPDNK. A 52-year-old woman with a background of CLPDNK was referred to dermatology with a painful rash primarily affecting her back. Skin biopsies revealed a neurotropic atypical lymphoid infiltration. Results of immunohistochemistry studies showed CD8, CD56, granzyme B, perforin positivity, and CD3 negativity in keeping with an atypical neurotropic lymphoid infiltrate consistent with cutaneous involvement by the patient's known CLPDNK. Cutaneous lesions and peripheral neuropathy in patients with CLPDNK have been reported; however, the involvement of cutaneous peripheral nerves as described in our case has not been reported before. Correspondence: Sarah Ní Mhaolcatha, Department of Pathology, Cork University Hospital, Cork, Ireland (e-mail: Sarah.Nimhaolcatha@hse.ie). The authors declare no conflicts of interest. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.

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