Primary cutaneous CD30+ anaplastic large-cell lymphomas mimicking keratoacanthomas.

Primary cutaneous anaplastic large cell lymphoma (ALCL) may be associated with keratoacanthoma (KA)-like epithelial hyperplasia and dense eosinophilic and neutrophilic infiltrates. Diagnosis in such cases is challenging both clinically and histologically, because the large atypical lymphoid cells may be obscured by the massive infiltrate of eosinophils and neutrophils, or confused with invasive squamous cell carcinoma or KA. We recently encountered two cases of CD30+ ALCL presenting with a KA-like tumour on the eyelid and nose, respectively. One showed features of KA histologically, with marked tissue eosinophilia and neutrophilia.