Acute promyelocytic leukaemia: looking through 'gums'.

To cite: Jain A, Lad D, Malhotra P, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/bcr-2016217457 DESCRIPTION Examination of the oral cavity provides valuable clues to a large number of systemic disorders. Gum hypertrophy is usually associated with myelomonocytic and monocytic subtypes of acute myeloid leukaemia. Its occurrence in a case of acute promyelocytic leukaemia (APL) is unusual. We describe a 28-year-old man from India who presented to our hospital with a 2-week history of easy fatiguability and gum bleeding. Examination revealed pallor and marked gum hypertrophy (figure 1). Blood investigations showed haemoglobin 50 g/L, white cell count 5.4×10/L, differential counts 95% promyelocytes, 3% myelocytes, 1% metamyelocytes and 1% neutrophils, platelets 30×10/L, prothrombin time 18 s (control 14 s), activated partial thromboplastin time 42 s (control 34–36 s) and fibrinogen 1.5 g/L (2–4 g/L). Examination of the bone marrow aspirate smears revealed typical Faggot cells (figure 2A, B). Conventional karyotyping revealed t(15;17). PML-RARα was detected in the bone marrow aspirate by reverse transcriptase PCR (RT-PCR). The patient was diagnosed as a case of APL (intermediate risk) and treated with a combination of all-trans-retinoic acid (45 mg/m/day) and arsenic trioxide (0.15 mg/kg/day). Gum hypertrophy resolved within 2 weeks of initiating the therapy. The patient achieved a complete