Haemangioblastomas are relatively rare primary vascular tumours, typically occurring in the cerebellum of adults. They are histologically benign lesions consisting of lipid-laden stromal cells within a well-defined capillary network. They may be solid or cystic and are often very vascular. They occur sporadically or as part of von Hippel-Lindau disease (VHL). We were only able to find twenty-five cases occurring in pregnancy, described in the literature (1-14), and consequently it has been difficult to draw conclusions regarding their relationship to pregnancy. We describe two cases of cerebellar haemangioblastomas that presented in pregnancy, which support the theory that pregnancy may indeed accelerate tumour growth.
Case 1: A 22 year old woman presented in the twenty ninth week of her second pregnancy. She complained of three days of worsening ataxia and headache. Throughout her pregnancy, she had been experiencing daily nausea and vomiting. In addition, her right arm had weakened over the prior two months. On examination, she had bilateral papilloedema, and right arm weakness, as well as left cerebellar signs. A CT scan of the brain demonstrated a mixed solid/ cystic, contrast enhancing midline posterior fossa mass, causing obstruction of the fourth ventricle and hydrocephalus. An external ventricular drain was inserted on the day of admission, followed two days later with a posterior fossa craniectomy and resection of the tumour. At operation, the tumour was found to be extremely vascular, with the patient requiring a transfusion of seven units of packed red cells during the six-hour procedure. The tumour was completely resected, and histologically confirmed to be a haemangioblastoma. The patient had an uneventful postoperative course, with the external drain being removed thirteen days after insertion. She was reviewed clinically for evidence of Von Hippel-Lindau disease, and it was determined that this was a sporadic haemangioblastoma. She is at present awaiting an elective caesarean section, scheduled for her thirty eighth week of pregnancy.
Case 2: A 23 year old woman presented in her thirtieth week of her second pregnancy. She complained of a week of worsening ataxia and diplopia, associated with headache, nausea and vomiting for three weeks. Examination revealed bilateral papilloedema, a left abducens nerve palsy, and mild cerebellar signs in the left lower limb. CT scan of the brain showed a contrast enhancing midline posterior fossa mass, with both cystic and solid components, and associated hydrocephalus.(Fig.1) Again, clinical workup showed that this was a sporadic haemangioblastoma. The patient’s management was similar, with the insertion of an external ventricular drain, followed two days later by a posterior fossa craniectomy. At surgery, the tumour was again noted to be extremely vascular, with the procedure taking six and a half hours, and the patient needing four units of packed red cells peri-operatively. The tumour was completely resected and confirmed to be a haemangioblastoma. The patient had an uncomplicated postoperative course, with the drain being removed seven days after insertion. She went on to deliver a healthy infant.
The effect of pregnancy on the natural history of brain tumours is unclear. Cushing and Bailey stated that pregnancy was a provocative factor for angiomatous tumours, but they were not able to prove this with their data (3). Roelvink et al (12) in their review of the effect of pregnancy on the manifestation or acceleration of symptoms of brain and spinal tumours in pregnancy found that the incidence of brain tumours that become symptomatic in pregnancy is not more than that in age matched women and the frequency of different primary tumours is not changed by pregnancy. However they found that different types of tumours are influenced at different stages of pregnancy (1). With the possible exception of Robinson’s series (11), haemangioblastomas are probably not over-represented among all pregnant women presenting with brain tumours (2). There is therefore no evidence that there is an increased incidence of haemangioblastomas in pregnancy. In VHL disease, it is classic that pregnancy can be accompanied by the enlargement of a cyst in a few months, sometimes leading to dramatic complications both for the mother and the fetus (10). A number of authors have however observed that there appears to be acceleration in the rate of growth and subsequently development of symptoms of haemangioblastoma in pregnancy (2-9). The expansion of the tumour’s vascular bed and the maternal blood volume, as well as hormonal influences have been used to explain the rapid progression in pregnancy (2, 3, 4, 7,13, 14). There appears to be an equal presentation of haemangioblastomas in the first and third trimesters of pregnancy (7). One can speculate that in those patients presenting in the first trimester the tumour has already attained a critical size and then rapidly becomes symptomatic due to the vascular engorgement or hormonal influences on the tumour itself (7). The postulated role of hormonal factors was further strengthened by the demonstration of progesterone receptors in haemangioblastomas by Brown et al.(2) In addition, the intravascular volume reaches its maximum in the third trimester; this would explain the development of symptoms and rapid tumour growth due to engorgement in this period. Both of our patients presented in the third trimester with a rapid progression of symptoms, supporting the hypothesis that increased intravascular volume contributed to the engorgement and enlargement of the haemangioblastomas. Haemangioblastomas are normally highly vascular tumours and can bleed profusely at surgery. Logically, a vascular tumour could be expected to increase its vascularity due to the vascular engorgement associated with pregnancy. Both of our patients had more profuse bleeding at surgery than expected, requiring significant transfusions. It is our opinion that this increased vascularity of pregnancy not only results in accelerated tumour enlargement, but adds the additional risk of intra-operative bleeding to this surgery and that both surgeon and anaesthetist should be cognoscent of this in their preoperative planning.