Final answer:
A bone marrow biopsy in essential thrombocytosis would show an increased number of megakaryocytes, the cells that produce platelets, as well as potential abnormalities in their morphology.
Step-by-step explanation:
In essential thrombocytosis, a bone marrow biopsy would typically show an increased number of megakaryocytes, which are the large bone marrow cells responsible for the production of platelets (thrombocytes). Essential thrombocytosis is a condition classified under myeloproliferative disorders, where there is an overproduction of platelets leading to thrombocytosis, which is an abnormally high platelet count, as opposed to thrombocytopenia, which is an abnormally low platelet count and can result in bleeding disorders like hemophilia.
Megakaryocytes are stimulated to proliferate by thrombopoietin, a glycoprotein hormone secreted mainly by the liver and kidneys. In the case of essential thrombocytosis, the bone marrow biopsy may also reveal abnormalities in the morphology of megakaryocytes, such as clustering and hypersegmentation of the nuclei. Unlike other conditions that might cause secondary thrombocytosis, essential thrombocytosis is a primary disorder of the bone marrow.