A case report: Type II Abernethy malformation complicated with congenital polydactyly and enlargement of all cardiac chambers.

Background: Abernethy malformation is a kind of congenital malformation of portal vein system caused by abnormal portacaval anastomosis. It can be in combination with other congenital malformations. The major therapy of Abernethy malformation is surgery. There has been a limited number of patients since the first patient reported, leading to a limited view towards this kind of disease until now. Results: In August 2018 we treated a patient diagnosed with typeII Abernethy malformation complicated with both congenital polydactyly and enlargement of all cardiac chambers, which is extremely rare and can be a supplementary to the existing cases. Besides, the low white blood cell and platelet, the arrested megakaryocytic maturation and the positive platelet autoantibody in serum may result in misdiagnosis as immune thrombocytopenia, so we analyze the differential points between these two diseases. We treated this patient with silybin orally and advised him to make follow-up visits because of his mild liver function disorder, normal cardiac function and no other malformations or complications complicated. At the latest follow-up, we knew the condition of the patient was generally satisfactory, whether in terms of laboratory test results or his daily life experience. Conclusions: Because of some changes of spleen in form and function secondary to Abernethy malformation, in some cases, this disease has similarities with a part of blood diseases, which we should take into consideration for differential diagnosis, especially when other congenital malformations are found in combination at the same time. This case also suggests that simply conservative treatment with regular follow-up visits can be suitable for certain patients.

malformation complicated with both congenital polydactyly and enlargement of all cardiac chambers, which is extremely rare and can be a supplementary to the existing cases. Besides, the low white blood cell and platelet, the arrested megakaryocytic maturation and the positive platelet autoantibody in serum may result in misdiagnosis as immune thrombocytopenia, so we analyze the differential points between these two diseases. We treated this patient with silybin orally and advised him to make follow-up visits because of his mild liver function disorder, normal cardiac function and no other malformations or complications complicated.
At the latest follow-up, we knew the condition of the patient was generally satisfactory, whether in terms of laboratory test results or his daily life experience.
Conclusions: Because of some changes of spleen in form and function secondary to Abernethy malformation, in some cases, this disease has similarities with a part of blood diseases, which we should take into consideration for differential diagnosis, especially when other congenital malformations are found in combination at the same time. This case also suggests that simply conservative treatment with regular follow-up visits can be suitable for certain patients. 3

Background
Abernethy malformation, a rare hepatic vascular malformation, is a kind of congenital malformation of portal vein system caused by abnormal portacaval anastomosis. According to whether the portal vein is absent completely or not, it can be divided into two types. TypeⅠ, to which many female and pediatric patients belong, means a total lack of portal vein, patients in this type usually have a short medical history as a result of the rapid progress like liver failure, while patients in typeⅡ often have a relatively long medical history for its incomplete absence of portal vein [1]. There has been a limited number of patients since the first patient reported by Abernethy in 1797 [2], leading to a limited view towards this kind of disease until now. This patient was complicated with congenital polydactyly and enlargement of all cardiac chambers, which is extremely rare and can be a supplementary to the existing cases. Besides, his arrested megakaryocytic maturation and positive platelet autoantibody in serum may result in misdiagnosis as immune thrombocytopenia, which reminds us to take a part of blood diseases into consideration for differential diagnosis.

Patient Information
We treated the patient in August 2018. His diagnosis is typeⅡ Abernethy malformation complicated with both congenital polydactyly and enlargement of all cardiac chambers. This patient is a 16-year-old boy with a 6-year history of low white blood cell (WBC) and platelet levels. Routine blood tests over the past 6 years showed that his WBC counts ranged from 2.36 × 10 9 /L to 3.87 × 10 9 /L and his platelets ranged from 48 × 10 9 /L to 72 × 10 9 /L, while those for erythrocytes and 4 hemoglobin were normal. The results of a bone marrow cytology test and bone marrow biopsy in other hospitals showed normal erythroid proliferation, while the granulocytic and megakaryocytic maturation was arrested. The results of fluorescent in situ hybridization (FISH) suggested neither − 7/7q-, the absence of gene EGR1 (5q31) or D20S108, nor increased numbers of chromosome 8. According to our inquiry, his parents and other immediate family were all normal.

Clinical Findings
After this patient was admitted to our hospital, we gave him basic physical examination and found his spleen was palpated at the bottom of the ribs with a second line 10.0 centimeters long, both of his hands had six fingers and the surplus thumb on the right hand had been resected several years earlier, leaving a small and deformed one (Fig. 1A). A small amount of convex tissue was present on the medial surface of his normal left thumb which was considered to be an incompletely developed finger that was not painful when touched (Fig. 1B). In addition, we gave

Diagnostic Assessment
In consideration of these symptoms and examination results, the patient was diagnosed with type Ⅱ Abernethy malformation complicated with congenital polydactyly and enlargement of all cardiac chambers. With regard to this patient, a differential diagnosis with immune thrombocytopenia (ITP) should be taken into consideration for the arrested megakaryocytic maturation and the presence of platelet autoantibodies. Although arrested megakaryocytic maturation and platelet autoantibodies can be observed in ITP patients, 70% of them do not have splenomegaly. Moreover, when diagnosing ITP, secondary thrombocytopenia must be excluded. However, hypersplenism secondary to Abernethy malformation could not be ruled out because the decreased WBCs and platelets may also occur in the early phase of hypersplenism.

Therapeutic Intervention, Follow-up and Outcomes 6
Because the patient's liver function was mild disorder, cardiac function was normal despite the enlargement of all cardiac chambers and no malformations or complications associated with other systems were found. We suggested that he simply take silybin orally for a period and make regular follow-up visits. We attained at the latest follow-up that the his platelets were 70 × 10 9 /L and WBCs were 3.81 × 10 9 /L, he did not complain of any discomfort.

Patient Perspective
This patient is a student with general family economic conditions, the conservative therapy neither keep him from normal study and life, nor bring much financial burden to his family. The treatment effect is also accordance with his and his parents' expected one, they are willing to cooperate with the next follow-up visits.

Discussion
Abernethy malformation is a rare congenital vascular malformation that can be in combination with other congenital malformations such as cardiovascular malformations, biliary atresia, choledochus cysts, and polysplenia [3]. This case adds Abernethy malformation with both congenital polydactyly and enlargement of all cardiac chambers to that list. Besides, Abernethy malformation may lead to some changes of spleen in form and function, which can further bring hematological changes. Before this patient was admitted in our hospital, the reason making his laboratory tests abnormal was largely considered to be related to blood diseases.
Indeed, Abernethy malformation and a part of blood diseases have some similarites that maybe lead to misdiagnosis easily, but we should attach importance to basic laboratory examinations and not let some results hinder our diagnosis thinking. Last 7 but not least, although the major therapy of Abernethy malformation is surgery, simply conservative treatment with regular follow-up visits can also be suitable for certain patients, this depends on a comprehensive assessment of patients' condition.

Conclusion
In some cases, Abernethy malformation has similarities with a part of blood diseases, which we should take into consideration for differential diagnosis, especially when other congenital malformations are found in combination at the same time. This case also suggests that simply conservative treatment with regular follow-up visits can be suitable for certain patients.

Declarations
Funding: None received.
Availability of data and materials: Data are available by request.
Ethics approval and consent to participate Ethical committee of Qi-lu hospital of Shandong University approved our study. Consent for publication: We have obtained permission from the patient for the purpose of publication, We promise that our team take responsibility for the anonymization of the patient.
Competing interests: We declare that we have no competing interests.