Genital vasculitis secondary to all-trans-retinoic-acid.

Acute promyelocytic leukaemia is among the most curable haematological malignancies after the introduction of differentiating agents (arsenic trioxide (ATO) and all-trans-retinoic-acid (ATRA)). Despite excellent cure rates, approaching 85-95% in various series, APL is associated with significant early mortality and morbidity. ATRA-related side effects partly contribute to this morbidity, which commonly presents as differentiation syndrome, pseudo tumour cerebri, dermatitis, gastrointestinal disorders, liver dysfunction (raised transaminases) and dryness of skin/eyes. Rarely, ATRA can lead to hypercalcaemia, genital vasculitis, erythaema nodosum and Sweet's syndrome. We present two cases of ATRA-associated genital vasculitis while being managed with a combination of ATO with ATRA therapy. Both patients developed these lesions despite being on prophylactic steroids (0.5 mg/kg). We also discuss the pathophysiology, clinical manifestations, differential diagnosis and treatment of genital vasculitis as a rare adverse event of ATRA.