No abstract

Sézary syndrome is a rare leukemic type of cutaneous T-cell lymphoma characterized by the presence of neoplastic T cells with cerebriform nuclei (Sézary cells) in the skin, lymph nodes, and peripheral blood. Typical Sézary cells have a CD3+CD4+CD8– phenotype; however, in cases of the aberrant loss of antigens on Sézary cells, especially the loss of critically important T-cell antigens such as CD4, there is a possibility of misdiagnosing the disease or underestimating the tumor burden of the disease. Here, we report a rare case of Sézary syndrome with CD4/CD8 double-negative Sézary cells in the peripheral blood. Most of the Sézary cells in the peripheral blood had lost CD4 expression, and we diagnosed the disease and evaluated the tumor burden by multicolor flow cytometry. Intriguingly, the Sézary cells showed a typical CD4+CD8–CD7– phenotype in the skin even though the cells in the peripheral blood lacked CD4. The patient responded well to treatment with bexarotene and narrow-band ultraviolet B therapy. Analysis by multicolor flow cytometry is essential to diagnose this rare type of Sézary syndrome and evaluate the tumor burden.

Richter’s syndrome (RS) of the central nervous system (CNS) is known to have an extremely poor prognosis. Ibrutinib has been reported to have some activity in patients with RS, despite its poor prognosis. Although ibrutinib crosses the blood-brain barrier, its efficacy in RS patients with CNS involvement remains unknown. Here, we report a case of RS isolated in the CNS that was confirmed to be clonally related to chronic lymphocytic leukemia (CLL) by immunoglobulin heavy chain gene analysis. Although the median survival of patients with RS clonally related to CLL was significantly shorter than that of patients with RS clonally unrelated to CLL, the patient received ibrutinib monotherapy without experiencing any significant adverse events, and the disease remained stable with ibrutinib until 6 weeks later. Following whole-brain radiation therapy (40 Gy in 20 fractions) with dexamethasone, the patient has survived for five months after diagnosis. Thus, ibrutinib may be a safe and effective therapeutic option for patients with RS and CNS involvement.

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