Eosinophilic folliculitis, eosinophilic dermatosis of hematologic malignancy and acneiform follicular mucinosis: Two case reports and a review of the literature highlighting the spectrum of histopathology.

Within the literature, there is overlap in the histopathological features described in eosinophilic folliculitis associated with chronic lymphocytic leukemia (CLL), eosinophilic dermatosis of hematologic malignancy, and acneiform follicular mucinosis. These disorders are described with varying degrees of superficial and deep lymphocytic and eosinophilic inflammation demonstrating perivascular, perifollicular, and folliculocentric involvement with or without follicular mucin deposition. Given significant histopathological overlap, these diagnoses may represent a continuum on a spectrum of dermatoses. Here, we present two cases with histopathological elements that reflect components of this clinicopathological spectrum and compare our findings with previously reported cases to compare and contrast reported features. Our first case is a 71-year-old African American man with long-standing CLL who developed a pruritic erythematous papular eruption on the face and chest with biopsy revealing a dense folliculotropic lymphocytic infiltrate with conspicuous eosinophils and follicular mucinosis. Our second case is a 70-year-old Caucasian man recently diagnosed with CLL/small lymphocytic lymphoma who developed an erythematous papular rash on the neck and face with biopsy revealing superficial and deep perivascular and periadnexal lymphocytic inflammation with scattered eosinophils. Characterization of our two cases and comparison with available literature suggest that these disorders may represent a continuum of dermatoses.
(© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)