Chronic Myeloid Leukaemia Presented with Extreme Isolated Thrombocytosis

CML presenting with isolated extreme thrombocytosis is rare. We reported a 47 years old man who presented with history of right sided lower abdominal pain, vomiting, significant lethargy and chest tightness. Patient was mildly anaemic and abdominal examination revealed no organomegaly. On investigation, he was found to have extreme thrombocytosis (2050x109/L) and mild leucocytosis (31.7 x109/L) with mild anaemia. In view of extreme thrombocytosis, he was investigated for myeloproliferative disease especially essential thrombocythemia. He was found to be positive for BCR-ABL by reverse transcription PCR (RT-PCR) and negative for JAK2, CALR, MPL mutations. Ultimately, he was diagnosed as a case of CML with an atypical presentation. He received imatinib 400 mg/day and achieve complete haematological response at 15 days.