Pediatric case of primary cutaneous eosinophil-rich CD30+ anaplastic large-cell lymphoma with follicular mucinosis.

We report a pediatric case of primary cutaneous CD30 anaplastic large-cell lymphoma showing a combination of rare histopathologic features. The patient was a 14-year-old boy who had a solitary 2 × 1-cm ulcerated nodule with purulent discharge and undermined borders located in the right preauricular area that had been present for 3 weeks. Histopathologically, there was a dense, nonepidermotropic multinodular to diffuse infiltrate involving the reticular dermis and, focally, the subcutis. The infiltrate was composed of numerous eosinophils, neutrophils, small well-differentiated lymphocytes, and large pleomorphic and anaplastic cells. Eosinophils dominated the infiltrate. Focally, the infiltrate was accentuated around hair follicles, many of which manifested features of follicular mucinosis and/or collections of neutrophils in the follicular epithelium. Occasional hair follicles were partly destroyed by the infiltrate. A conspicuous feature was a prominent myxoid change in the stroma surrounding the hair follicles and eccrine glands. Immunohistochemically, the large lymphoid cells expressed CD2, CD3, CD4, and CD30.