Usefulness of Flow Cytometry for the Detection of Cutaneous Localization in Malignant Hematologic Disorders.

BACKGROUND: Histological evaluation of malignant hematologic involvement of the skin can be challenging and needs an extended immunohistochemistry panel. We assessed the ability of flow cytometry (FCM) to detect neoplastic cell subsets in skin biopsies as a useful tool that supplements the histological examination in a complementary way. METHODS: Two hundred and forty-three consecutive skin biopsies were retrospectively analyzed between April 2012 and July 2017. RESULTS: Among them, 147 samples, corresponding to 128 patients, were analyzed at diagnosis. Eighty-seven patients had erythrodermic inflammatory dermatoses, and 41 patients had cutaneous hematologic neoplasms. Cutaneous T-cell lymphomas were the most frequent disorders, accounting for 70% of cases (29/41). Cutaneous B-cell lymphoma was found in only 17% of cases (7/41) and immature hematologic malignancies in 5% (2/41). Three patients had secondary skin involvement. The sensitivity of FCM skin biopsy analysis was 78.1% (32/41). Among the 243 samples, 27 patients had mycosis fungoides (MF) or Sezary syndrome (SS) with available FCM data. A loss of CD26 expression was identified in 92% of cases of transformed MF or SS versus 40% of cases of non-transformed MF (P = 0.0057 χ²). Among the 12 MF patients with negative CD26 expression, six progressed to SS versus none in the positive group (50% vs. 0% P = 0.0168 χ²). CONCLUSIONS: FCM analysis of the skin biopsies is a sensitive method and a useful tool for improving the sensitivity of diagnosis of hematologic skin neoplasms. Among the MF patients, a loss of CD26 expression could be a marker of higher risk of progression. © 2019 International Clinical Cytometry Society.

Vasculitis associated with large granular lymphocyte (LGL) leukemia: presentation and treatment outcomes of 11 cases.

OBJECTIVE: The association between vasculitis and large granular lymphocyte (LGL) leukemia has rarely been reported or investigated. Thus, we assessed the clinical and biological phenotypes of LGL leukemia associated with vasculitis. RESULTS: We studied a series of 11 patients displaying LGL leukemia associated with vasculitis (LAV). The mean age at diagnosis of LGL leukemia was 60.3 years; there were nine women and two men. The mean follow-up period was 45 months. The main LGL lineage was T-LGL (10 patients), and only one NK-LGL was identified. Clinical and biological features of T-LGL leukemia were compared with those from the 2009 French T-LGL registry. We did not find any relevant differences except that patients with LAV were predominantly female (p < 0.05). The most frequently observed vasculitis was cryoglobulinemia (n = 5). Three patients presented with cutaneous leukocytoclastic angiitis, two patients had ANCA-negative microscopic polyangiitis, and one patient had giant cell arteritis. The main clinical features involved the skin, e.g., purpura (91%), arthralgia (37%), peripheral neuritis (27%), and renal glomerulonephritis (18%). The most frequent histologic finding was leucocytoclastic vasculitis (54%). The rate of complete remission was high; i.e., 80%. A minority of patients had a vasculitis relapse (27%). Three patients (27%) died; one death was related to LGL leukemia (acute infection) and the two other deaths were related to vasculitis (both with heart failure). CONCLUSION: We conclude that vasculitis is overrepresented in the population of LGL patients, LAV predominantly affects women, vasculitis preferentially affects the small vessels, and LAV has high rate of complete response.

Hematogones: a new prognostic factor for acute myeloblastic leukemia.

Acute myeloid leukemia (AML) patient outcomes remain heterogeneous, and new prognostic tools are needed to assess the risk of relapse. Hematogones (HGs) are normal B-lymphocyte precursors, which increase in number in hematologic diseases. The prognostic impact of the presence of detectable HGs on the leukemia-free survival (LFS) and overall survival of 120 consecutive patients with AML in first complete remission was investigated by flow cytometry. Patients who had HG levels more than 0.01% had a significantly better median LFS (29.2 vs 11.7 months; P = .001) and overall survival (not reached vs 23.5 months; P = .011). According to Cox analysis, an HG level more than 0.01% was an independent predictor of LFS (hazard ratio = 0.5; 95% confidence interval, 0.28-0.90, P < .03) when age, leukocytosis, the number of chemotherapy cycles, and the standardized cytogenetic and molecular risk subgroups were controlled for. These results indicate that HG analysis may help to define the risk of relapse in AML patients.