Ectopic Recurrence of Arteriovenous Malformation After Radiosurgery: Case Report and Insight Regarding Pathogenesis.

BACKGROUND: While prior studies reporting de novo arteriovenous malformations after birth are not uncommon, reports of ectopic recurrence of arteriovenous malformation after radiotherapy are scarce. CASE DESCRIPTION: An 8-year-old girl with a ruptured cerebellar arteriovenous malformation was treated with stereotactic radiosurgery. The nidus was completely obliterated 17 months after stereotactic radiosurgery; however, 20 years later she had a rupture of a recurrent nidus that occurred adjacent to the original nidus, accompanied by a radiation-induced cyst. Surgical resection was performed, and subsequent pathologic examination revealed 2 different compartments: a typical nidus and a postirradiated degenerated nidus with an encapsulated hematoma. Immunohistochemical stains showed increased expression of Ki-67 and decreased expression of endoglin in endothelial cells in the recurrent nidus. CONCLUSIONS: Depletion in endoglin may lead to the formation of vessel malformations in the presence of angiogenic stimuli. This case serves as a strong reminder of the importance of long-term follow-up after stereotactic radiosurgery, especially for pediatric cases.

Stereotactic radiosurgery for Spetzler-Martin Grade III arteriovenous malformations: an international multicenter study.

OBJECTIVE Because of the angioarchitectural diversity of Spetzler-Martin (SM) Grade III arteriovenous malformations (AVMs), the management of these lesions is incompletely defined. The aims of this multicenter, retrospective cohort study were to evaluate the outcomes after stereotactic radiosurgery (SRS) for SM Grade III AVMs and to determine the factors predicting these outcomes. METHODS The authors analyzed and pooled data from patients with SM Grade III AVMs treated with SRS at 8 institutions participating in the International Gamma Knife Research Foundation. Patients with these AVMs and a minimum follow-up length of 12 months were included in the study cohort. An optimal outcome was defined as AVM obliteration, no post-SRS hemorrhage, and no permanently symptomatic radiation-induced changes (RICs). Data were analyzed by univariate and multivariate regression analyses. RESULTS The SM Grade III AVM cohort comprised 891 patients with a mean age of 34 years at the time of SRS. The mean nidus volume, radiosurgical margin dose, and follow-up length were 4.5 cm3, 20 Gy, and 89 months, respectively. The actuarial obliteration rates at 5 and 10 years were 63% and 78%, respectively. The annual postradiosurgery hemorrhage rate was 1.2%. Symptomatic and permanent RICs were observed in 11% and 4% of the patients, respectively. Optimal outcome was achieved in 56% of the patients and was significantly more frequent in cases of unruptured AVMs (OR 2.3, p < 0.001). The lack of a previous hemorrhage (p = 0.037), absence of previous AVM embolization (p = 0.002), smaller nidus volume (p = 0.014), absence of AVM-associated arterial aneurysms (p = 0.023), and higher margin dose (p < 0.001) were statistically significant independent predictors of optimal outcome in a multivariate analysis. CONCLUSIONS Stereotactic radiosurgery provided better outcomes for patients with small, unruptured SM Grade III AVMs than for large or ruptured SM Grade III nidi. A prospective trial or registry that facilitates a comparison of SRS with conservative AVM management might further clarify the authors' observations for these often high-risk AVMs.

An unusual approach to the spontaneous rupture of hepatocellular carcinoma.

Our aim is to describe an unusual approach to the spontaneous rupture of a large hepatocellular carcinoma (HCC). A 45-year-old man, Hepatitis C virus (+) (HCV+), complaining of abdominal pain. During the investigation, a tumor affecting liver segments V, VI, VII and VIII, with the presence of fluid within the peritoneal cavity, suggesting hemoperitoneum, was found. The patient was submitted to an exploratory laparotomy, revealing a large hepatic tumor mass with capsule rupture in segment V, biopsy verified the diagnosis of HCC. After one week, a superselective chemoembolization of the nutrient artery of the tumor was performed; one month later, the patient was submitted to an embolization of the right portal branch, aimed at causing hypertrophy of the left lateral portion of the liver. A right hepatectomy was performed, as well as a nodulectomy in segment II, without complications along the 40 days subsequent to the portal embolization. The patient is currently on his 53rd postoperative month and evidences no tumor recurrence to the moment. Although the spontaneous rupture of HCC is uncommon, it can be today treated by combining interventionist radiology procedures and conventional liver resections, offering the patient a better chance of survival.