Articles on Medical Diseases and Conditions

Entries Tagged ‘Myeloproliferative Syndromes’

Langerhans’ Cell Histiocytosis (Histiocytosis X)

This term was coined to describe three closely related disorders characterized by proliferation of the Langerhans cell, a type of histiocyte. Histiocytosis X was the original term used for this group of diseases. The group comprises three well-known disorders and several rarer ones. Letterer-Siwe disease is a rapidly progressive, fatal condition that is seen mostly […]

Immunosuppressive Lymphoproliferative Disorders (ILDs)

These diseases occur predominantly in organ transplant patients and HIV-infected patients, but may appear in patients with congenital immune defects or those having immunosuppressive therapy for other conditions. Some of these lymphoid proliferations are benign, some are malignant, and some are initially benign (using current tests) but later acquire clinical and laboratory evidence of malignancy. […]

Malignant Lymphomas

The malignant lymphomas include Hodgkin’s disease and non-Hodgkin’s lymphomas; both are derived from lymphoid tissue, predominantly from lymph nodes. Lymph nodes are composed of two parts, germinal centers and lymphoreticular tissue. The germinal centers contain lymphoblasts and reticulum cells; these produce the mature lymphocytes and reticulum cells that form the remainder of the lymphoid tissue. […]


Polycythemia is an increase in the total blood RBCs over the upper limit of the reference range. This usually entails a concurrent increase in hemoglobin and hematocrit values. Since various studies disagree somewhat on the values that should be considered the upper limits of normal, partially arbitrary criteria are used to define polycythemia. A hemoglobin […]

Differential Diagnosis of Chronic Myelogenous Leukemia, Agnogenic Myeloid Metaplasia, and Leukemoid Reaction

When CML has the typical picture of a WBC count more than 100,000/mm3 (100 x 109/L) with myelocytic predominance, increased platelets, and basophilia, the diagnosis is reasonably safe. Otherwise, the two conditions that most frequently enter the differential diagnosis are agnogenic myeloid metaplasia and leukemoid reaction. CML tends to have a greater degree of leukocytosis […]

Leukemoid Reaction

Leukemoid reaction is an abnormally marked granulocytic response to some bone marrow stimulus, most commonly infection. Leukemoid reaction is basically the same process as an ordinary leukocytosis except in the degree of response. The expected peripheral blood WBC count response is even more marked than usual and may reach the 50,000-100,000/mm3 (50-100 x 109/L) range […]

Agnogenic Myeloid Metaplasia

A disease that is often very difficult to separate from CML is agnogenic (idiopathic) myeloid metaplasia (AMM). It is most common in persons aged 50-60 years. The syndrome results from bone marrow failure and subsequent extramedullary hematopoiesis on a large scale in the spleen and sometimes in the liver and lymph nodes. Actually, the extramedullary […]

Chronic Myelogenous (granulocytic) Leukemia (CML)

CML is most common between the ages of 20 and 50 and is rare in childhood. It comprises about 20% of all leukemias. There is an increased (total) peripheral WBC count in more than 95% of patients, with about 70% more than 50,000/mm3 (50 Ч 109/L) and about 45% more than 100,000/mm3. There is usually […]

Chronic Lymphocytic Leukemia (CLL)

CLL comprises about 30% of all leukemias. It is uncommon in Asians. The lymphocytes of CLL are B-lymphocytes, although there are about 2%-3% (range, 2%-5%) of cases that consist of T-lymphocytes. The disease is usually found after the age of 50. It is twice as common in men than in women. Average survival is 3-7 […]

Hairy Cell Leukemia

This disease has now been classified as a B-lymphocyte disorder. A few variant patients, such as rare patients with T-cell characteristics, have been reported. A few cases have been reported in association with retrovirus HTLV-II infection. Hairy cell leukemia was originally called leukemic reticuloendotheliosis. It affects primarily men (male/female ratio 4:1) between ages 40 and […]