Marked Reactive Neutrophilia Due to Marrow Involvement by Anaplastic Thyroid Carcinoma: An Autopsy Case Study

Abstract

We report an exceptional autopsy case study of metastatic involvement of the bone marrow by anaplastic thyroid carcinoma which resulted in leukocytosis thought by the clinical service to be suspicious for chronic myelogenous leukemia (CML). Hematology results were based on automated analyzers (Sysmex XE-5000 and Beckman-Coulter LH 750) and manual blood smear review. Blood smears, autopsy examination, and pathology slides were made per standard UCSF Pathology and Laboratory Medicine clinical protocols. The patient was a 57-year old female with papillary thyroid carcinoma, originally treated with thyroidectomy in 1993, and a long history of metastatic disease. Upon hospital admission, complete blood count was as follows: WBC 89,400/microL (81% neutrophils with toxic changes and left shift without basophilia), hemoglobin 14.2 g/dL, platelets 106,000/microL. Manual 700-cell count results were as follows: 63% neutrophils, 15% bands, 5.5% metamyelocytes, 1.5% myelocytes, 0.1% promyelocytes, 0% blasts, 2% lymphocytes, 3% monocytes, 10% eosinophils, and 0% basophils. Peripheral blood was sent for BCR-ABL RT-PCR and was negative. On the day of the patient's death her WBC reached 106,100/microL. The patient died of overwhelming tumor burden and pulmonary lymphangiitic spread. At autopsy, there was diffuse metastatic disease, the majority of which was consistent with anaplastic transformation. Tumor was present in the neck, thoracic and abdominal lymph nodes, lungs, heart, diaphragm, liver, omentum, peritoneum, small intestine, kidneys, and multiple foci in the spine. The bone marrow showed numerous foci of tumor. The uninvolved marrow was hypercellular for age (70%) with granulocytic predominance, without evidence of myeloproliferative disorder. Leukemoid reactions are not uncommon in the presence of widely metastatic cancer and are associated with worse prognosis. However, the degree of leukocytosis in this case, causing clinical suspicion for CML, is not common. Save for the presence of underlying tumor, this hematologic lesion would meet WHO 2008 criteria for chronic neutrophilic leukemia.