[Relapse of acute lymphoblastic leukemia as a retro-orbital mass]

A 16-year-old girl who had been treated for B-precursor acute lymphoblastic leukemia (ALL) presented with a mass in the left orbit as an isolated relapse. Five years earlier, she had undergone chemotherapy that promptly resulted in a complete remission. For prophylaxis of central nervons system leukemia, the patient received cranial radiotherapy (18 Gy) with shielding of the orbit and 15 cycles of intrathecal MTX and prednisolone. Cerebrospinal fluid analysis did not detect infiltration during the treatment course. Exophthalmos of the eft eye and hyperemia of the conjuctiva developed 15 months after therapy. Computed tomography showed a retro-orbital mass behind the left eye. Though bone marrow aspiration was negative, biopsy specimens from the mass disclosed the infiltration of CD10-positive leukemic blasts. After 8 courses of chemotherapy, 5 cycles of intrathecal MTX, and orbital irradiation (24 Gy), the mass disappeared. All relapse as an isolated retro-orbital mass is very rare, and only 3 cases have been reported to date.