Case report
A 64-year-old man was referred to our Department of Dermatology with a
1-day history of annular erythema on his trunk. The patient was
diagnosed with Philadelphia chromosome-positive B-ALL based on the
finding of the infiltration of leukemia cells with CD79α, CD10, and
terminal deoxynucleotidyl transferase (Tdt) antigens into the bone
marrow 9 months previously. The patient was treated with combination
chemotherapy consisting of cyclophosphamide, vincristine, doxorubicin,
and dexamethasone, resulting in complete remission, followed by
consolidation therapy with dasatinib. However, the recurrence of B-ALL
was confirmed 5 months previously based on the detection of bcr/abl mRNA
of 4,100,000 copies/μg RNA by a real-time polymerase chain reaction.
Therefore, the patient was referred to our Department of
Oncology/Hematology and was treated with blinatumomab (1 course of 42
days; 9 μg/day on days 1 to 7, 28 μg/day on days 8 to 28, and washout on
days 29 to 42).
On day 5 in the 4th course of blinatumomab, the patient developed
erythema on his trunk. On day 6, he visited our Department of
Dermatology for the eruption and we noted multiple erythema with an
annular appearance and ranging in size from 2 to 5 cm in diameter on his
trunk (Figure 1). A histopathological examination of erythema showed
that mononuclear cells with dense chromatin and mild atypia infiltrated
the nucleus around the vessels and adnexa in the dermis and a few
mitotic cells were present (Figure 2a and 2b). An immunohistochemical
analysis revealed that infiltrating mononuclear cells were reactive to
anti-CD79α, CD10, and terminal Tdt antibodies (Figure 2c, 2d, and 2e,
respectively), which was compatible with the bone marrow findings
observed 9 months previously. Cutaneous manifestations were diagnosed as
LC due to B-ALL and disappeared on day 7 in the 4th course, leaving only
pale pigmentation when treated with topical corticosteroids.