Arginase-1+ bone marrow myeloid cells are reduced in myeloproliferative neoplasms and correlate with clinical phenotype, fibrosis, and molecular driver.

INTRODUCTION: Philadelphia-negative myeloproliferative neoplasms (MPN) are clonal myeloid proliferative disorders characterized by sustained systemic inflammation. Despite its renowned importance, the knowledge concerning the inflammatory pathophysiology of these conditions is currently limited to studies on serum cytokines, while cellular immunity has rarely been investigated. METHODS: In the present study, we targeted Arginase-1 immunosuppressive myeloid cells in the bone marrow of MPN patients and healthy controls and investigated their clinical and prognostic significance. We demonstrated that MPN are characterized by a significant reduction of bone marrow immunosuppressive cells and that the number of these cells significantly correlates with several clinical and histopathological features of diagnostic and prognostic importance. Moreover, we identified an unreported correlation between a reduction of Arginase-1+ bone marrow cells and the presence of CALR mutations, linking tumor-promoting immunity and molecular drivers. Finally, we postulate that the reduction of bone marrow Arginase-1+ immunosuppressive cells may be due to the migration of these cells to the spleen, where they may exert systemic immunomodulatory function. CONCLUSION: Altogether, this study preliminary investigated the contribution of cellular immunity in the pathogenesis of myeloproliferative neoplasms and identified a possible interesting therapeutic target as well as a set of new links that may contribute to unraveling the biological mechanisms behind these interesting hematological neoplasms.

Intralymphatic Histiocytosis Associated With Tubo-ovarian High-grade Serous Carcinoma: Case Report and Review of the Literature.

Intralymphatic histiocytosis is a condition characterized by the accumulation of mononuclear phagocytes within lymphatic vessels and lymph nodes that may be isolated or secondary to autoimmune or neoplastic diseases. Secondary intralymphatic histiocytosis frequently involves the skin and is associated with malignancies in up to a tenth of cases. We describe a case of intralymphatic histiocytosis associated with high-grade serous carcinoma and reviewed the literature on neoplasia associated with the broader category of histiocytoses with raisinoid nuclei. Moreover, we try to elucidate the pathogenesis of these rare and intriguing disorders.

Bilateral Ovarian Malakoplakia: Case Report and Review of the Literature With Clinical and Diagnostic Considerations.

Malakoplakia is a rare condition in which histiocytic cells accumulate within different organs and tissues, sometimes mimicking neoplasia. Gynecologic involvement is extremely rare and therefore may cause relevant diagnostic confusion for both clinicians and pathologists. In this paper, we described the seventh case of ovarian malakoplakia, and we reviewed the literature to compare it with the previously reported ones. Moreover, we investigated the histologic and molecular differential diagnosis of malakoplakia, with special attention to other histiocytic disorders of gynecologic interest. Finally, we discussed the most relevant points with regard to possible pathogenesis and management. Malakoplakia often represents a forgotten entity that should be remembered preoperatively, when approaching a possible gynecologic neoplasia. Moreover, it is of remarkable importance to differentiate malakoplakia from multisystem histiocytosis involving gynecologic organs. All this would prevent misdiagnosis and overtreatment of such a rare but benign condition.