Recurrent, Isolated Factor X Deficiency in Myeloma: Repeated Normalization of Factor X Levels after Cytostatic Chemotherapy Followed by Late Treatment Failure Associated with the Development of Systemic Amyloidosis

Acquired factor X deficiency in a multiple myeloma without amyloidosis: a case report

BACKGROUND

Multiple myeloma is one of the most common hematologic malignancies. Acquired factor X deficiencies are often observed in primary (AL) amyloidosis and rarely in multiple myeloma.

OBJECTIVE

We report a case of an acquired factor X deficiency in a patient with a newly diagnosed IgA lambda multiple myeloma, without any evidence of concomitant amyloidosis.

METHODS

We present the patient's medical history, clinical and physical examinations, laboratory analysis, and outcome.

RESULTS

A 76-year-old male presented at the emergency department with ongoing gingival bleeding. Several analytical problems with blood sample analysis arose, which eventually led to the diagnosis of a multiple myeloma. Further exploration revealed an acquired factor X deficiency, explaining the ongoing bleeding. There was no evidence of concomitant amyloidosis. The multiple myeloma was treated, leading to complete remission of the malignancy and bleeding tendency.

CONCLUSION

While coagulopathy is rarely observed in patients diagnosed with multiple myeloma, considering an acquired factor X deficiency becomes relevant when such patient present with bleeding diathesis.

Factor X deficiency

Factor X is one of the vitamin K-dependent serine proteases. It plays a crucial role in the coagulation cascade, as the first enzyme in the common pathway of thrombus formation. The gene for factor X maps to the long arm of chromosome 13, approximately 2.8 kb downstream of the factor VII gene. The gene consists of eight exons, each of which encodes a specific functional domain within the protein. Both the gene structure and the amino acid sequence show homology to other vitamin K-dependent clotting factors, suggesting their origin in a common ancestral protein. Factor X deficiency is one of the rarest of the inherited coagulation disorders. Inheritance is in an autosomal recessive manner. The clinical phenotype is of a variable bleeding tendency. Homozygous factor X deficiency has an incidence of 1:1,000,000 in the general population. Heterozygotes are often clinically asymptomatic. Acquired factor X deficiency is rare, but when it occurs it is usually in association with amyloidosis. Treatment of factor X deficiency involves replacement of the protein with either fresh frozen plasma or prothrombin complex concentrates, although the latter should be used with caution as infusion may be associated with an increased risk of thrombosis.

Successful treatment of an acquired haemorrhagic diathesis due to factor X deficiency with chemotherapy

A 70-yr-old woman presented with a severe haemorrhagic diathesis due to an acquired factor X deficiency. A plasma infusion study showed that exogenous factor X was eliminated very effectively from the patient's circulation. A bone marrow biopsy was consistent with plasma cell dyscrasia. Neither an abdominal fat biopsy nor the bone marrow biopsy confirmed an amyloidosis, although clinically no other diagnosis seemed possible. Treatment with intermittent chemotherapy, consisting of vincristine, cytoxan and prednisone, yielded definite clinical and laboratory improvement.

Acquired factor X deficiency in patients with amyloid light-chain amyloidosis: incidence, bleeding manifestations, and response to high-dose chemotherapy

Acquired deficiency of factor X occurs in patients with systemic amyloid light-chain (AL) amyloidosis, presumably due to adsorption of factor X to amyloid fibrils. Of 368 consecutive patients with systemic AL amyloidosis evaluated at Boston Medical Center, 32 patients (8.7%) had factor X levels below 50% of normal. Eighteen of these patients (56%) had bleeding complications, which were more frequent and severe in the 12 patients below 25% of normal; 2 episodes were fatal. Ten factor X-deficient patients received high-dose melphalan chemotherapy followed by autologous stem cell transplantation. Of 7 patients alive 1 year after treatment, 4 had a complete hematologic response, and all 4 experienced improvement in their factor X levels. One of 2 additional patients with partial hematologic responses had improvement in factor X. Thus, aggressive treatment of the underlying plasma cell dyscrasia in AL amyloidosis can lead to the amelioration of amyloid-related factor X deficiency.

Hemostatic Changes in Patients with Malignancy

Alterations of hemostasis commonly accompany the progression of malignant disease and every known component of the hemostatic mechanism may be affected by this disease process. Nearly all patients with an active neoplasm will exhibit at least subtle biochemical changes in hemostasis, and a minority of these patients will also develop clinical thrombosis or hemorrhage. In this paper, we will review intravascular coagulation and fibrinolysis, thrombocytopenia, and thrombocytosis, as well as more rare thrombotic and hemorrhagic events resulting from the direct interactions of neoplasms, or of their products, with the individual elements of hemostatic mechanisms. Thrombotic and hemorrhagic events resulting from the induction of autoimmune or thrombotic microangiopathic syndromes are also discussed. This review focuses on the clinical thrombotic and bleeding syndromes that may occur as a result of this interaction between neoplasia and hemostasis.

Coagulation disorders in cancer

Coagulation disorders are common in cancer patients. This article reviews the coagulation laboratory findings in these patients and the thromboembolic and hemorrhagic manifestations of malignancy. Among the many topics addressed are Trousseau's syndrome, disseminated intravascular coagulation, and acquired von Willebrand disease. Pathogenesis of the coagulation disorders and recommendations for treatment of various syndromes are discussed.

Unusual bleeding manifestations in a case of primary amyloidosis with factor X deficiency but elevations of in vivo markers of thrombin formation and activity

We describe a case of primary amyloidosis (AL) with severe factor X (FX) deficiency in an amateur cyclist presenting with muscular pain at rest and ecchymoses in his legs. No circulating inhibitor of FX was found by mixing studies and there was no deficiency of other vitamin K-dependent coagulation factors and inhibitors or of alpha 2-antiplasmin. Thrombin-time and reptilase time were abnormally prolonged and were not corrected by mixing with normal plasma. Administration of plasma or prothrombin complex concentrate (PCC) were unsuccessful in controlling bleeding: the apparent half-life of transfused FX was 6 minutes. Resting resulted in cessation of muscular pain and bleeding. Renal and cardiac deterioration led the patient to death 3 years after presentation. No further bleeding manifestations did occur during this period. FX levels remained consistently below 3%, but prothrombin fragment 1.2 and thrombin-antithrombin complex--measured at distance from PCC administration and prior to deterioration of renal and cardiac function--were markedly elevated. At autopsy, disseminated amyloidosis was found with sparing of the skeletal muscles and of the skin. This is the first report of increased in vivo prothrombin activation and activity in AL-associated FX deficiency.

Biochemistry of factor X

Factor X circulates as a serine protease which is converted to the active form at the point of convergence of the intrinsic and extrinsic coagulation pathways. Subsequently, the enzymatic species, factor Xa, is involved in macromolecular complex formation with its cofactor factor Va, a phospholipid surface and calcium to convert prothrombin into thrombin. The gene encoding factor X shares a number of structural and organisational features in common with the other vitamin K-dependent coagulation proteins, suggesting that they have evolved from a common ancestral gene. Each of the exons encoding these proteins can be considered as a module coding for a homologous domain in each protein. These structural domains in factor X are responsible for specific functional properties including gamma-carboxylase recognition, calcium binding, phospholipid surface interaction, as well as cofactor and substrate binding. Studies of recombinant proteins and proteolytic fragments continue to provide significant insight into structure-function relationships of the protein modules within factor X.