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.

Regulation of RhoB Gene Expression during Tumorigenesis and Aging Process and Its Potential Applications in These Processes.

RhoB, a member of the Ras homolog gene family and GTPase, regulates intracellular signaling pathways by interfacing with epidermal growth factor receptor (EGFR), Ras, and phosphatidylinositol 3-kinase (PI3K)/Akt to modulate responses in cellular structure and function. Notably, the EGFR, Ras, and PI3K/Akt pathways can lead to downregulation of RhoB, while simultaneously being associated with an increased propensity for tumorigenesis. Functionally, RhoB, part of the Rho GTPase family, regulates intracellular signaling pathways by interfacing with EGFR, RAS, and PI3K/Akt/mammalian target of rapamycin (mTOR), and MYC pathways to modulate responses in cellular structure and function. Notably, the EGFR, Ras, and PI3K/Akt pathways can lead to downregulation of RhoB, while simultaneously being associated with an increased propensity for tumorigenesis. RHOB expression has a complex regulatory backdrop consisting of multiple histone deacetyltransferase (HDACs 1 and 6) and microRNA (miR-19a, -21, and -223)-mediated mechanisms of modifying expression. The interwoven nature of RhoB's regulatory impact and cellular roles in regulating intracellular vesicle trafficking, cell motion, and the cell cycle lays the foundation for analyzing the link between loss of RhoB and tumorigenesis within the context of age-related decline in RhoB. RhoB appears to play a tissue-specific role in tumorigenesis, as such, uncovering and appreciating the potential for restoration of RHOB expression as a mechanism for cancer prevention or therapeutics serves as a practical application. An in-depth assessment of RhoB will serve as a springboard for investigating and characterizing this key component of numerous intracellular messaging and regulatory pathways that may hold the connection between aging and tumorigenesis.