Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare haematological malignancy with an aggressive clinical course. It has been recognised as a distinct entity in the WHO 2008 classification of haematolymphoid neoplasm. This disease usually presents with cutaneous involvement as the first manifestation, with subsequent or simultaneous spread to bone marrow and peripheral blood with leukaemic dissemination. Gingival lesion as the first manifestation, in the absence of a cutaneous lesion, is an uncommon presentation of this rare disease. We report a case of an elderly woman, aged 84 years, who presented with a lump on the mandibular gingiva and ipsilateral otalgia without any cutaneous lesion and associated with an highly aggressive and rapid leukaemia. This case is an addition to the handful of those cases of BPDCN which presents without cutaneous involvement, but it is exceedingly rare for clinical features that make it a unique case in the literature.