individuals with a hematologic malignancy may have an immunosuppressive condition and develop cutaneous or invasive bacterial infections .
the infections may be a first sign of a malignancy or a sign of a relapse .
acute promyelocytic leukemia ( apl ; acute myeloid leukemia m3 ) is caused by balanced reciprocal chromosomal translocation t(15;17 ) , which produces an oncogenic protein pml - rara by fusion of the promyelocytic leukemia gene ( pml ) and the retinoic acid receptor a gene ( rara ) .
apl is created by a blockage of differentiation , resulting in overproduction of immature myeloid cells of promyelocytes in the bone marrow .
we herein report a 71-year - old man with cellulitis as a first sign of apl .
a 71-year - old man was referred to us on october 2011 with a painful eruption on the right thigh that had appeared 12 days earlier .
a physical examination revealed a swollen and painful erythematous lesion with an elevated temperature ( 38.6c ) on the right thigh ( fig .
laboratory blood examination results were as follows : white blood cell count 1,300/l with neutrophils 18.4% ( band neutrophils 10.0% and segmented neutrophils 8.4% ) , lymphocytes 56.0% , monocytes 0.3% , eosinophils 0% , basophils 0% , metamyelocytes 1.3% and leukemic cells 24.0% ; red blood cells 3.29  10/l ; hemoglobin 11.5 g / dl ; platelets 11.9 10/l ; c - reactive protein 18.526 mg / dl ; soluble interleukin-2 1,249 u / ml ; ferritin 607 ng / ml ; c3 170 mg / dl ; c4 36 mg / dl ; ch50 73.8 u / ml ; fibrinogen 632 mg / dl ; fibrin degradation product 24.1 g / ml ; antithrombin iii 109% ; thrombin - antithrombin iii complex 6.3 ng / ml ; plasmin - a2 plasmin inhibitor complex 3.1 g / ml ; d - dimer 15.8/g / ml , and endotoxin less than 5.0 pg / ml . blood cultures showed no bacterial growth .
g - band testing of twenty bone marrow cells showed 46,xy , t(15;17)(q22;q12 ) in 19 cells and 46,xy in 1 cell .
all - trans retinoic acid ( atra ) , idarubicin hydrochloride , and cytarabine were administered after the bacterial infection had been eliminated .
one month after the administration of atra , a sample of bone marrow cells contained the following : myeloblasts 2.1% ; promyelocytes 3.5% ; myelocytes 21.8% ; metamyelocytes 20.2% ; band neutrophils 12.0% , and segmented neutrophils 5.6% .
apl cells can be forced to differentiate in the presence of atra . in this case
, a bone marrow examination indicated that the apl cells differentiated into maturing cells after the administration of atra .
patients with leukemia are predisposed to pancytopenia , and may show infectious disorders resulting from leukocytopenia , purpura resulting from thrombocytopenia , and shortness of breath resulting from erythrocytopenia .
cellulitis may develop secondary to a bacterial infection in patients with leukemia , including apl .
cellulitis is an inflammation of loose connective tissue of dermal and subcutaneous tissue , and is caused by bacterial infection .
however , cellulitis without leukocytosis may be present in patients with malignant hematologic disorders as shown here , or in persons with cold cellulitis by cutaneous leishmaniasis   or leprosy .
girmenia et al .   reported that their analysis of septicemias in apl patients receiving atra and idarubicin showed a significantly lower rate of bloodstream infections , even though patients receiving atra occasionally suffered life - threatening and lethal infections .
the authors noted that 6 of 89 patients with apl withdrew from antileukemic treatment due to infections .
infection control before and during the treatment is indispensable for individuals with apl , even though septicemias are less frequent in apl than in other leukemias .
dermatologists and hematologists should keep in mind that patients with a hematologic malignancy , such as apl , can develop cellulitis with leukocytopenia .
 patients with hematologic malignancies are immunosuppressive and may develop cutaneous or invasive infections as a primary sign of immune suppression . 
 acute promyelocytic leukemia ( acute myeloid leukemia m3 ) is caused by translocation of reciprocal chromosomal rearrangement t(15;17 ) , which produces an oncogenic protein . 
 we herein describe a 71-year - old man having cellulitis with leukocytopenia as a first sign of acute promyelocytic leukemia . 
 dermatologists and hematologists should keep in mind that patients with a hematologic malignancy , such as acute promyelocytic leukemia , can develop cellulitis with leukocytopenia . 