Hematological Paraneoplastic Syndrome

Cancer may affect the cellular elements of the blood as well as the coagulation system, resulting in a wide range of paraneoplastic syndromes (Table 3). In modern health-care systems routine hematological testing is so common that many cancers are first detected by one of these paraneoplastic syndromes.

5.1. Red Blood Cells Disorders

Anemia: Anemia of cancer is probably the most common paraneoplastic syndrome [18]. It is usually characterized by a normochromic or mild hypochromic red blood cell (RBC) morphology with low serum iron and increased ferritin levels. The etiology is probably due to low erythropoietin levels mediated by cytokines such as interleukin-1 (IL-1), and tumor necrosis factor (TNF) [19],

Autoimmune hemolytic anemia occurs by both warm and cold antibodies. It predominates in chronic lymphatic leukemia (CLL) and B-cell lymphomas. In most of these cases the autoantibody is polyclonal and appears to be a result of immune dysregulation and not a direct tumor product. Another proposed mechanism includes the RBC as an innocent bystander due to a cross reacting tumor antigen.

Another paraneoplastic phenomenon of obscure pathogenesis is microangiopathic hemolytic anemia with azotemia which is usually associated with gastric adenocarcinoma.

5.2. Erythrocytosis

The most common tumor associated with erythrocytosis is renal cell carcinoma. The presumed mechanism is a tumor mediated increase in erythropoietin secretion. Other types of tumors include cerebellar he-mangioblastomas, sarcomas and pheochromocytomas [20],

5.3. Leukocyte Disorders

Leukocytosis: Leukocytosis with neutrophil counts of up to 50- 107/L are not uncommon in malignancy [21]. This phenomenon is due to cytokine release (IL-1 or granulocyte-colony-stimulating factor) and its differentiation from the myeloproliferative disorder is sometime difficult. Eosinophilia has frequently been associated with Hodgkin's disease.

Neutropenia: Neutropenia has only rarely been described as a paraneoplastic disorder; in these cases, antigranulocytes antibodies have been found.

5.4. Platelet Disorders

Thrombocytopenia: Thrombocytopenia resulting from a paraneoplastic phenomenon is uncommon. Although autoimmune thrombocytopenia has been reported in CLL and B-cell lymphomas, it can hardly be differentiated from that caused by hypersplenism or direct bone-marrow replacement.

Thrombocytosis: Paraneoplastic thrombocytosis results from IL-6 and thrombopoietin release and it might play a role in the hypercoagulable state which affects many cancer patients.

Functional disorders: Abnormal platelet aggregation studies have been reported in primary dermatological malignancies, as well as in some solid tumors. In most cases these defects are minor, but they can sometimes aggravate a pre-existing thrombocytopenia.

5.5. Hemostatic Disorders

Thrombosis: The association of cancer and deep vein thrombosis (DVT) has been widely described and diagnosis of cancer has followed in many patients presenting with DVT without obvious risk factors [22], The presence of accentuated sub-clinical thrombotic activity has been detected in most advanced cancers by finding procoagulant activators secreted by tumor cells such as sialic acid, phospholipids and various cytokines. Mucin-producing tumors of the GI tract, lung and pelvic organs are most commonly associated with DVT and pulmonary embolism, but may also present as nonbacterial endocarditis or Budd-Chiari syndrome [23],

Hemorrhage: Abnormal coagulation activity can result also in hemorrhage due to consumption of clotting factors and platelets, thus causing DIC. The most common malignant disease causing DIC is acute premye-locytic leukemia. Another bleeding disorder reported

Table 3. Autoantibodies associated with paraneoplastic neurological disorders

Antibody

Antigens

Neuronal specificity

Associated tumors

Clinical disorders

Anti-Hu (ANNA-1)

35^10 kD

All types of neuronal nuclei

SCLC, sarcoma

Encephalomyelitis

10 Ways To Fight Off Cancer

10 Ways To Fight Off Cancer

Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.

Get My Free Ebook


Post a comment