In acute leukemia Chloromas are rare; exact estimates of their prevalence are lacking, but they are uncommonly seen even by physicians specializing in the treatment of leukemia. Chloromas may be somewhat more common in patients with the following disease features: * French-American-British (FAB) classification class M2 * WHO Classification (2016 revision) is a separate entity under the "Acute<unk>  leukemia (AML) and related neoplasms" * those with specific cytogenetic abnormalities (e.g. t(8;21) or inv(16)) * those whose myeloblasts express T-cell surface markers, CD13, or CD14 * those with high peripheral white blood cell counts However, even in patients with the above risk factors, chloroma remains an uncommon complication of acute<unk>  leukemia. Rarely, a chloroma can develop as the sole manifestation of relapse after apparently successful treatment of acute<unk>  leukemia. In keeping with the general behavior of chloromas, such an event must be regarded as an early herald of a systemic relapse, rather than as a localized process. In one review of 24 patients who developed isolated chloromas after treatment for acute<unk>  leukemia, the mean interval until bone marrow relapse was 7 months (range, 1 to 19 months). In myeloproliferative or<unk> ysplastic syndromes Chloromas may occur in patients with a diagnosis of<unk> ysplastic syndrome (MDS) or myeloproliferative syndromes (MPS) (e.g. chronic myelogenous leukemia (CML), polycythemia vera, essential thrombocytosis, or myelofibrosis). The detection of a chloroma is considered de facto evidence these premalignant conditions have transformed into an acute leukemia requiring appropriate treatment. For example, presence of a chloroma is sufficient to indicate chronic myelogenous leukemia has entered its 'blast crisis' phase. In Eosinophilic leukemia At least one case of FIP1L1-PDGFRA fusion gene-induced eosinophilic leukemia presenting with<unk>  and eosinophilia has been reported. This form of<unk>  is distinguished by its highly successful treatment with imatinib (the recommended treatment for FIP1L1-PDGRGA fusion gene-induced eosinophilic leukemia) rather than more aggressive and toxic therapy. Primary chloroma Very rarely, chloroma can occur without a known pre-existing or concomitant diagnosis of acute leukemia, acute promyelocytic leukemia or MDS/MPS; this is known as primary chloroma. Diagnosis is particularly challenging in this situation (see below). In almost all reported cases of primary chloroma, acute leukemia has developed shortly afterward (median time to development of acute leukemia 7 months, range 1–25 months). Therefore, primary chloroma could be considered an initial manifestation of acute leukemia, rather than a localized process, and could be treated as such. Where disease development or markers indicate progresses to acute promyleocytic leukemia (AML3) treatment should be tailored to this form of disease.
Myeloid sarcoma
Malignant histiocytosis
Ameloblastic carcinoma
B-cell lymphoma
Mixed-cell lymphoma
Non-X histiocytosis
Non-Langerhans cell histiocytosis
Gray zone lymphoma