Acute promyelocytic leukaemia (APML) is characterised by the t(15;17)(q22;q21), that results in the fusion of the promyelocytic leukaemia (PML) gene at 15q22 with the retinoic acid α-receptor (RARA) gene at 17q21. The current case report describes a 13-year-old male with APML, who was negative for PML/RARA fusion signal but reported to have an atypical translocation t(16;17). To the best of our knowledge this is the first case report of APML responsive to ATRA with such a translocation.

Acute promyelocytic leukemia (APML) is considered to be sensitive to all-trans-retinoic acid (ATRA) which acts as a differentiating agent. ATRA is considered to be a well-tolerated agent and is known to achieve complete remission in acute promyelocytic leukemia. However, a few cases on long term all-trans-retinoic acid (ATRA) use can develop pseudotumor cerebri. Out of 32 patients with APML who were treated in our Centre over a 4-year-period, we encountered 6 patients who developed ATRA-related pseudotumor cerebri while on maintenance treatment. The patients ranged from 12 to 40 years of age. 3 patients complained of unbearable headache, 2 of diplopia and 1 of gross reduction in visual acuity. CT scans and MRI did not reveal any intracranial lesions. Cerebrospinal fluid (CSF) examination was normal with CSF manometry revealing a high CSF pressure (average of 345mmH2O). Fundoscopy revealed papilledema in 5 patients and optic atrophy in 1 patient. The patients were successfully managed with decrease dose/discontinuation of ATRA, use of acetazolamide, corticosteroids and therapeutic CSF drainage.