Hypogranular Platelets in a 78-Year-Old Man

Patient: 78-year-old white man Chief Complaint : Abdominal aortic aneurysm with thrombocytopenia History of Present Illness: The patient has had a mildly decreased platelet count since 2004, which had become progressively lower. He had started taking a new oral hypoglycemic agent, sitagliptin phosphate (Januvia; Merck and Co, Inc, Whitehouse Station, NJ), in 2006 for his type-2 diabetes; there was speculation at the time that the decrease in platelets (Table 1) was related to the addition of this new medication to his regimen. No increased mucocutaneous bleeding was noted. No serious hemostatic challenges such as major surgery were recorded. Medical History: The patient has multiple comorbidities, including hypertension, hyperlipidemia, chronic renal insufficiency, coronary artery disease, post-myocardial infarction, atrial fibrillation, diabetes mellitus, congestive heart failure, erosive gastritis, and duodenal adenomas. Medications: The patient takes multiple medications, including warfarin sodium (Coumadin; Bristol-Myers Squibb Company, New York, NY), furosemide (Lasix; Sanofi-Aventis LLC, Paris, France), simvastatin (Zocor; Merck and Co, Inc), sitagliptin phosphate (Januvia), glimepiride (Amaryl; Sanofi-Aventis LLC), pioglitazone (Actos; Takeda Pharmaceutical Co Ltd, Osaka, Japan), lisinopril, colesevelam (Welchol; Daiichi Sankyo Co Ltd, Tokyo, Japan), and cholestyramine. Family History: No family history of abnormal bleeding or clotting is noted. Physical Examination: The patient was alert and oriented to person, place, and time without acute distress. No purpura, petechiae, or ecchymoses were observed. No lymphadenopathy, hepatomegaly, or splenomegaly was present. The patient reported no fevers, night sweats, or unexplained weight loss. The review of systems revealed no other pertinent hematologic findings. Laboratory Findings: The bone marrow was slightly to moderately hypercellular, and all 3 cell lineages were present. The bone marrow contained an adequate number of megakaryocytes with normal morphology and without clusters or dysplastic features. The immunohistochemical stain for factor VIII–related antigen helped to enhance visualization of megakaryocytes, platelets, and endothelial cells. Granulopoiesis was increased …