HEPATIC CAVERNOUS HAEMANGIOMA: A 10 YEAR REVIEW

Between January 1981 and July 1991, 61 patients with hepatic haemangiomata were examined at Westmead Hospital. There were 14 males (22%) and 47 females (78%). The age range was 26–85 years with a median of 49 years. Forty-one had abdominal symptoms but these could be attributed to a haemangioma in only seven cases. There was at least one subcapsular lesion in 17 (28%). Six of the seven symptomatic lesions were subcapsular and five of these were giant haemangiomata (i.e. more than 4 cm in greatest diameter). One large symptomatic lesion was intrahepatic. No association was observed between hepatic haemangiomata and other hepatic or extrahepatic diseases. Haemangiomata were resected from six patients, four of whom were symptomatic. Symptoms improved in all four but did not resolve completely in any. Follow-up ranged from nil in five patients to 108 months in one. The median follow-up was 12 months after initial diagnosis. Ten patients showed evidence of change in their lesions or symptoms while under observation. Only three had worsening symptoms or suspected change in size of a haemangioma. This study highlights the benign, static nature of most hepatic haemangiomata. When this lesion is suspected, the diagnosis should be confirmed with ultrasound (US) and labelled red blood cell scanning (RBCS). Referral for evaluation by a specialist hepatobiliary surgery unit is necessary when symptoms are intolerable, increasing size is definitely demonstrated or the diagnosis is uncertain and cannot be established without specialized investigations. Bleeding into or from these lesions is rare.     

Laparoscopic hepatic resection

Background Although laparoscopy in general surgery is increasingly being performed, only recently has liver surgery been performed with laparoscopy. We critically review our experience with laparoscopic liver resections. Methods From January 2000 to April 2004, we performed laparoscopic hepatic resection in 16 patients with 18 hepatic lesions. Nine lesions were benign in seven patients (five hydatid cysts, three hemangiomas, and one simple cyst), five were malignant in five patients (five hepatocarcinoma), and four patients had an uncertain preoperative diagnosis (one suspected hemangioma and three suspected adenomas). The mean lesion size was 5.2 cm (range, 1–12). Twelve lesions were located in the left lobe, three were in segment VI, one was in segment V, one was in segment IV, and one was in the subcapsular part of segment VIII. Results The conversion rate was 6.2%; intraoperative bleeding requiring blood transfusions occurred in two patients. Mean operative time was 120 min. Mean hospital stay was 4 days (range, 2–7). There were no major postoperative complications and no mortality. Conclusions Hepatic resection with laparoscopy is feasible in malignant and benign hepatic lesions located in the left lobe and anterior inferior right lobe segments (IV, V, and VI). Results are similar to those of the open surgical technique in carefully selected cases, although studies with large numbers of patients are necessary to drawn definite conclusions.     

The management of periorbital fat excess in haemangioma involution.

Haemangioma of infancy is a common birthmark. As spontaneous involution is the rule, it is usually treated conservatively. Periorbital haemangiomata may require intervention if symptomatic and this may be early or late, where plastic surgery may be required. It has not previously been recognised that deep periorbital lesions may lead to a baggy appearance of the eyelids because of excess fatty tissue. The management of this condition is described in different clinical presentations illustrated by three female patients with a history of infantile periorbital haemangioma. Two were treated by blepharoplasty, during which an excess of fatty tissue was found, deep to the orbital septum. Birthmark stigmata were eradicated and symmetry was achieved.     

Size of lesion is not a criterion for resection during management of giant liver haemangioma

BACKGROUND: The unknown natural history and risk of complications of large haemangiomas may pose therapeutic dilemmas. The authors describe their experience with the management of giant haemangiomas. METHODS: Patients with a giant haemangioma were identified by a survey of the hospital database. Forty-nine patients with a haemangioma of at least 4 cm in diameter presented between January 1990 and December 2000. Medical records were analysed retrospectively. RESULTS: Eleven patients had surgical treatment and 38 were managed conservatively. The median diameter of the tumours was 8.0 cm in surgically treated patients and 6.0 cm in the group managed by observation. Surgery-related morbidity occurred in three patients, and abdominal complaints persisted in three of ten patients with a symptomatic lesion. During a median follow-up of 52 months, 12 non-operated patients had mild abdominal complaints, considered to be unrelated to the lesion. In these patients symptoms either diminished or became minimal during follow-up. Complications did not occur. CONCLUSION: Observation of giant haemangiomas can be performed safely. The authors advocate resection of cavernous liver haemangiomas only in patients with persistent severe symptoms.     

Management of cavernous hemangioma of the liver

Cavernous hemangioma of the liver was diagnosed in 12 of 60 patients (20 percent) evaluated for surgery of neoplastic liver disease. All were female, from 29 to 77 years old. Six patients presented with abdominal pain and seven had taken estrogens. Indications for surgery included uncertain diagnosis, symptoms, large lesion greater than or equal to 6 cm, and hypoproliferative anemia. Three right lobectomies, one left lateral segmentectomy, one open biopsy, and one right trisegmentectomy were performed. There were no deaths, one subphrenic abscess, and one bile leak. The remaining seven patients were observed and at 2 to 6 years post operatively had followed a benign course. Resectional therapy may be considered for superficial large or symptomatic lesions in the appropriate patient, but most hepatic hemangiomas follow a benign course.     

Benign and solid tumors of the liver: relationship to sex, age, size of tumors, and outcome

From 1983 through 1997, our center diagnosed 130 cases of benign neoplasms: 27 with focal nodular hyperplasia (FNH), 25 with hepatic adenoma, 71 with cavernous hemangioma, and seven with mixed tumors of different diagnoses. Most often these lesions were seen in females [female-to-male ratio (f/m): 5.5/1]. Hepatic adenomas and mixed tumors were seen exclusively in females and FNH predominantly in females (f/m: 26/1). Hemangiomas, however, were not uncommon in men (f/m: 52/19) relative to the other tumors (P < 0.001). Furthermore patients with hemangioma were older (mean age: 49 years) whereas patients with hepatic adenoma, FNH, and mixed tumors were often younger (mean age: 33, 35, and 44 years respectively; P < 0.004). Oral contraceptive steroid use was related by 21 of 25 patients (84%) with hepatic adenoma, 22 of 26 (85%) females with FNH, five of seven (71%) females with mixed tumors, and 10 of 52 (19%) patients with hemangioma. Ninety-five of the 130 patients (73%) had one or more symptoms. There was no statistically significant correlation between symptoms and the size of the lesion, the final diagnosis, and whether there were solitary or multiple masses. Three of 25 (12%) with hepatic adenoma presented with rupture, and one of 27 (4%) with FNH had such a consequence. None of the hemangiomas presented with rupture or progressed to such a state. One patient with hepatic adenoma (4%) had a focus of malignancy. Surgical removal of benign tumors was performed in 82 of 130 patients (63%), and there was one operative mortality (1.2%) in a patient who had a caudate lobe FNH. The types of surgical procedures included segmentectomy (62%), lobectomy (34%), and trisegmentectomy (4%). In two of 84 patients who had undergone laparotomy resection was not technically possible. Resection is recommended in all cases of hepatic adenoma because of fear of rupture or associated focus of malignancy. FNH was not observed to undergo a malignant transformation and will rarely rupture. Surgery is only recommended for symptomatic hemangioma, and size of the lesion is not a criterion for excision.     

Hypercalcemia in epidermoid carcinoma of the head and neck.

Hypercalcemia occurs rarely at the time of diagnosis in patients found to have epidermoid carcinoma of the head and neck. It is particularly unlike in those patients who present with potentially curable lesions. Only 2 of our 307 patients who presented with potentially curable lesions were hypercalcemic at the time of diagnosis. Two hundred thirty-eight of these patients were followed up for two years or until death. Of the 139 who did not remain free of disease, hypercalcemia of clinical significance developed in ten (7.2 per cent). Pseudohyperparathyroidism was the suspected cause in seven of twelve patients. Debilitating symptoms were present in all patients with serum calcium levels greater thn 12.0 mg/100 ml. Treatment, when given, was effective in alleviating gastrointestinal and central nervous system problems. Although usually temporary, symptomatic improvement was appreciated by most patients and family members.     

Management of 155 patients with benign liver tumours.

BACKGROUND: Benign hepatic tumours continue to represent a diagnostic and therapeutic challenge. This study evaluates the indications and results of resection compared with observation in patients with benign hepatic tumours. METHODS: Patients with a primary diagnosis of benign liver tumour were identified from a prospective database and evaluated retrospectively. RESULTS: From January 1992 to June 1999, 155 patients with benign hepatic tumours were evaluated. The diagnoses included haemangioma (n = 97), focal nodular hyperplasia (FNH) (n = 42), hepatic adenoma (n = 12) and cystadenoma (n = 4). Sixty-eight patients (44 per cent) underwent resection because of symptoms (n = 36), inability to exclude a malignancy (n = 31) or enlargement on serial imaging (n = 11). The operative morbidity and mortality rates were 21 per cent and zero respectively. Thirty patients had a preoperative percutaneous needle biopsy, 19 of which were either incorrect or indeterminate. Overall, 39 of 42 patients with symptoms attributed to the tumour were asymptomatic after resection and 18 of 21 patients with symptoms considered unrelated to the tumour were asymptomatic after a period of observation and/or treatment of unrelated conditions (median follow-up 16 months). CONCLUSION: When indicated, resection of benign liver tumours can be performed safely. Symptomatic patients with a small FNH or haemangioma can be observed because their symptoms are unlikely to be related to the liver tumour. Percutaneous needle biopsy rarely changes management.     

Successful Arterial Embolisation of Giant Liver Haemangioma

A 28-year old man presented with a symptomatic giant haemangioma. On June 26, 1983, at laparotomy, no resection was attempted because the lesion involved the right lobe of the liver and a part of segments II and III. The patient underwent a right hepatic arterial embolisation with gelatine sponge particles. During follow-up, the patient remained asymptomatic. Five-year review by CT-scan showed a diminution of the size of the haemangioma and hypertrophy of the left lobe. On October 21, 1988, the patient was reoperated on for liver abscess and complete necrosis of the haemangioma. A right hepatectomy was performed. In conclusion, the long-term effect of hepatic arterial embolisation, as demonstrated in our case by regular CT-scans, is useful in cases of diffuse haemangioma as an alternative to hazardous major liver resection. To our knowledge, the long-term effect of hepatic arterial embolisation on symptoms and tumor size have never been reported for giant liver haemangioma.     

Surgical treatment of hepatic haemangiomas: a 15-year experience

BACKGROUND: Hepatic haemangiomas are congenital vascular malformations. They are the most common benign tumours of the liver and are often asymptomatic. Spontaneous or traumatic rupture, intratumoral bleeding, consumption coagulopathy and rapid growth are the mandatory surgical indications. We present our experience over the last 15 years with the surgical management of 15 liver haemangiomas to clarify the safety and effectiveness of this treatment. METHODS: There were 15 patients with hepatic haemangiomas who were surgically treated from 1990 to 2004. Indications for the operation were spontaneous or traumatic rupture, consumption coagulopathy, rapid growth, abdominal pain and uncertain diagnosis. Four of these lesions were located on the left lobe, nine on the right lobe; one lesion was located on the left and the right lobes and one on segments VII and VIII. Methods for diagnosis included ultrasonography, computed tomography scan, magnetic resonance imaging and selective hepatic arteriography or combinations of more than one technique. RESULTS: The procedures included five right-extended lobectomies, five right lobectomies, one left-extended lobectomy, two left lobectomies and two segmental resections. There was no death. The postoperative morbidity was minimal and was mainly correlated to two subdiaphragmatic collections, one intra-abdominal collection and one wound infection. The postoperative hospital stay was 12.7 days (range, 10-19 days). During the follow-up period, there was no recurrence. CONCLUSION: The resection of the hepatic haemangioma is safe. The indications for resection, however, should be carefully analysed before embarking on such a major operation.     

Malignant masquerade at the hilum of the liver

Eight patients with biliary obstruction and a pre-operative diagnosis of a neoplastic lesion at the confluence of the hepatic ducts were found postoperatively to have benign disease. Cholangiography was highly suggestive of a malignant stricture in all patients. Angiography performed in six patients indicated that the lesions were potentially resectable. Seven patients underwent elective surgery; in six the ductal confluence including the lesion was removed, without mortality. Six patients are alive, five of them totally asymptomatic, in a median follow-up of 32 months. Many patients with hilar strictures are treated for what appears radiologically to be a neoplastic lesion. Since treatment often involves the placement of an endoprosthesis or palliative surgery, without histological diagnosis, some of these patients with benign disease are likely to be treated inappropriately, unless they are considered for a curative resection.     

Cystic type adrenal mass. Clinical-radiologic contribution to 7 cases treated with surgery

The aim of the study was to evaluate the accuracy of our imaging protocol with regard to adrenal masses of cystic nature. Seventy-four adrenal lesions were surgically removed over the period 1998-2002. Of these 7 were diagnosed as cysts or pseudocysts. All the patients were studied by abdominal US, CT and/or MRI. In 2 cases, an adrenal primary malignancy was suspected. The lesions of 2 more patients, radiologically identified as cysts, were interpreted as hepatic echinococcus cyst and mesenteric cyst, respectively; these patients underwent open surgery. In 3 cases an adrenal cystic tumour was correctly diagnosed and a laparoscopic adrenalectomy performed. The histopathological examination of the surgical specimens showed that the preoperative diagnosis failed to ascertain the true nature of the lesion in 4/7 cases (57%). The 2 suspected adrenal carcinomas turned out to be an epithelial cyst and a pseudocyst, respectively; the suspected hepatic echinococcus cyst and the mesenterial cyst were adrenal pseudocysts. Two of the 3 remaining cases were endothelial cysts and the third a pseudocysts. In the presence of adrenal masses of cystic nature, the preoperative diagnosis may easily be inaccurate and adversely influence the surgical approach, especially if a misdiagnosis of primary adrenal malignancy is made.     

Hepatic artery aneurysms: evolution from open to endovascular repair techniques

With the development of endovascular therapy, treatment for hepatic artery aneurysm (HAA) has evolved from open excision and repair to include endovascular approaches. We reviewed our recent experience with HAA to help define the treatment of HAA. From 2002 to 2010, five patients underwent treatment of HAA, all men with a median age of 63.2 years (range, 41-75). The median diameter of HAA was 5.8 cm (range, 2.4 cm-11 cm). Four lesions involved the extrahepatic portion of the hepatic artery, and one was an intrahepatic HAA that involved the right hepatic artery. Three were true aneurysms and two were pseudoaneurysms associated with trauma. Four of the five HAA patients were symptomatic, three with nonspecific abdominal pain, and one with free hemorrhage from a ruptured intrahepatic pseudoaneurysm. All five underwent computed tomography and selective arteriography. Two patients underwent open surgical aneurysmectomy and revascularization because of aneurysm location and concerns of the potential lack of collateral flow. Three patients underwent an endovascular coil embolization because obliteration of a saccular aneurysm could be achieved without compromising arterial flow of the native hepatic vessel. Re-embolization was necessary in the intrahepatic aneurysm because of recanalization of a feeding vessel. Endovascular embolization is an important minimally invasive approach in the treatment of HAA. Depending on HAA location and the adequacy of collateral arterial flow around the lesion, open aneurysmectomy and revascularization may be required.     

Giant Haemangioma of the Liver: Is Enucleation Better than Resection?

INTRODUCTION

Haemangioma is the most common liver tumour. Treatment is indicated for symptomatic tumours, rapid increase in size, rupture or doubt in diagnosis. There is continuing debate regarding the ideal method of surgical treatment for liver haemangiomas, with some surgeons favouring enucleation over liver resection.

PATIENTS AND METHODS

Retrospective analysis of prospectively compiled database of patients who were surgically treated for liver haemangioma.

RESULTS

Between 1987 and 2003, we operated on 21 patients with liver haemangioma. Pre-operative diagnosis on imaging was made in 16 patients (13 symptomatic, 3 had progressive increase in size). In five patients, the indication of surgery was uncertain diagnosis. Enucleation was performed in 9 patients and liver resection in 12. The size of the haemangioma was similar in the enucleation and resection groups (8.9 cm versus 10 cm; P = 0.85). The mean intra-operatiive blood loss was significantly less in the enucleation group (400 ml versus 1330 ml; P = 0.004). The mean operative time was significantly less in the enucleation group as compared to the resection group (170 min versus 230 min; P = 0.035). Five patients had major postoperative morbidity in the resection group as compared to none in the enucleation group (P = 0.045). The duration of hospital stay was significantly longer in the resection group.(9.9 days versus 5.6 days; P = 0.005).

CONCLUSIONS

Enucleation of liver haemangiomas is safer, quicker and associated with less morbidity than liver resection. Except for some situations, such as uncertain diagnosis or total replacement of a lobe, we recommend enucleation as the surgical procedures of choice for the treatment of hepatic haemangiomas.     

Benign liver tumors in adults: Diagnosis and management

Benign tumors of the liver are a heterogeneous group of lesions whose detection has greatly increased because of the widespread use of imaging techniques. Only a few types, such as cavernous hemangiomas, focal nodular hyperplasia (FNH), hepatic adenoma (HA), and cysts, are frequent enough to be of clinical importance. Although often asymptomatic, these tumors are sometimes associated with pain or digestive symptoms. In some of them, hormonal manipulation has a role in both the development and the course. Complications, such as spontaneous rupture or sudden increase in size, have been reported. Only in hepatic adenoma is malignant transformation considered possible. The clinical importance of these tumors lies mainly in making a correct diagnosis of the type of lesion, and in ruling out primary or metastatic tumors. Although most cases can now be identified through imaging techniques, in some, diagnosis remains uncertain even after percutaneous biopsy, making surgical exploration necessary. We here consider 104 patients with benign lesions: 60 underwent resection; the remaining 44 had follow up only. Of the former group, 35 had hemangiomas, 16 “cellular” tumors (either FNH or HA), and 9 cystic lesions. Forty-four were resected due to the presence of symptoms and 16 because of uncertain diagnosis. It is concluded that cavernous hemangioma, FNH, and most of the cysts have a favorable clinical evolution and, when the diagnosis is certain, resection is not indicated. Surgery can be considered for symptomatic or complicated cases and those in which the diagnosis remains uncertain with imaging work-up techniques. HA and cystic adenoma require surgical treatment even in asymptomatic patients.     

Benign lymphangioendothelioma (acquired progressive lymphangioma): a lesion not to be confused with well-differentiated angiosarcoma and patch stage Kaposi's sarcoma: clinicopathologic analysis of a series

The clinicopathologic features of 12 cases of benign lymphangioendothelioma (acquired progressive lymphangioma) are reported. There were five male and seven female patients. Age at diagnosis ranged from 17 to 90 years (median age, 54 yrs). Development of a single macular/papular hemangiomatous or pigmented lesion was the main presenting symptom. Symptom duration before diagnosis ranged from 2 months to 20 years (median, 5.5 yrs). Tumor size ranged from 0.3 cm to 10 cm (median. 1.5 cm). Location included skin of the head and neck (n = 5), back (n = 1), breast (n = 1), shoulder (n = 1), forearm (n = 1), plantar aspect of the foot (n = 2), and oral mucosa (n = 1). No patient had any other concomitant vascular anomaly (for example, lymphangiomatosis) or was suspected to have acquired immunodeficiency syndrome. Treatment consisted of excisional biopsy in nine patients, incisional biopsy in two, and wide excision in one. Follow-up information on nine patients (range, 4-40 mos; median, 12 mos) showed two local recurrences in one patient. Microscopically, the lesions consisted of anastomosing, often widely dilated vascular structures developing in the superficial dermis. As the lesion grew within deeper dermis, the vascular spaces collapsed and dissected the dermal collagen in an angiosarcoma-like pattern. The lining endothelium was flat and monolayered, with little or no cytologic atypia and no evident mitoses. Some vascular structures contained stromal papillary projections resembling papillary endothelial hyperplasia, and intravascular red blood cells were present occasionally. Immunohistochemistry performed in eight specimens showed variable endothelial cell reactivity for CD31 (7 of 8), CD34 (7 of 7), and factor VIII-related antigen (4 of 6). A smooth muscle cell layer was observed focally around the vascular spaces in six lesions. Benign lymphangioendothelioma (acquired progressive lymphangioma) is an uncommon benign lesion that, in view of major differences in treatment and prognosis, should be distinguished from well-differentiated angiosarcoma and Kaposi's sarcoma, especially the patch stage and lymphangioma-like variants of the latter.     

Cytoreductive hepatic surgery for neuroendocrine tumors.

We retrospectively reviewed 37 patients who underwent hepatic resection between 1970 and 1989 to evaluate the role of cytoreductive hepatic surgery in patients with metastatic neuroendocrine tumors (carcinoid, 24; islet cell, 13). Seventeen resections were curative (no gross residual tumor); nine patients had symptomatic endocrinopathies and seven patients had symptoms caused by the primary tumor. Eight of nine patients with symptomatic endorcrinopathies obtained complete relief of symptoms; five are alive with no evidence of disease at 2 to 82 months (mean, 26 months). Six of seven patients with symptoms caused by the primary tumor obtained complete relief; five are alive with no evidence of disease at 5 to 28 months (mean, 14 months). One symptom-free patient underwent curative hepatic resection 5 years after abdominoperineal resection for a rectal carcinoid. Twenty resections were palliative (gross residual tumor); 16 patients had symptomatic endocrinopathies and 4 patients had symptoms caused by the primary tumor. Eight of 16 patients with symptomatic endocrinopathies obtained complete relief; five are alive at 2 to 30 months (mean, 11 months), with a mean duration of complete relief of 6 months (3 to 12 months). All four patients who underwent resection for symptoms caused by the primary tumor obtained complete relief; two are alive and symptom free at 10 and 101 months. Our experience suggests that curative surgery should be considered in all patients with completely resectable metastatic disease and that palliative surgery, despite the short duration of complete relief, should be considered in selected patients because it delays and may reduce the subsequent need for medical therapy.     

Nonneoplastic peripheral nerve tumors

Most of the nonneoplastic tumor-like lesions affecting the peripheral nervous system are rarely encountered. In many situations, a good history of the presenting symptoms can suggest a reactive or infectious neuroma. The physical examination can also suggest an inflammatory or hyperplastic lesion. In some cases, however, the correct diagnosis can only be made at surgery. Nonetheless, awareness of these lesions is important in limiting unnecessarily aggressive surgical procedures. Patients suspected of having nonneoplastic lesions are followed and treated surgically for symptomatic relief or when the diagnosis is unclear. In some situations, the surgical treatment of choice may be debated. Nevertheless, we adopt a conservative approach to these lesions and reserve more aggressive techniques for cases that do not respond to more conservative means.     

Segmental atrophy of the liver: a distinctive pseudotumor of the liver with variable histologic appearances

Segmental atrophy of the liver can lead to the formation of a pseudotumor that can pose a diagnostic challenge. To better understand the full clinicopathologic spectrum of this pseudotumor, 18 cases were studied. Ages at presentation ranged from 14 to 91 years (median, 63 y) with a modest female-patient predominance (13 of 18, 72%). Upper right quadrant abdominal pain was the most common clinical presentation (14 of 18, 78%), and all the cases were mass lesions. The majority of cases were subcapsular (15 of 18, 83%) and ranged in size from 1.8 to 10.0 cm. All the cases contained abnormally thick-walled and often thrombosed vessels, with both arteries and veins affected. Biliary cysts were a common finding (7 of 18, 39%). Examination of the entire series of cases suggested a sequence of changes, with early lesions (n = 4) composed of collapsed hepatic parenchyma with preservation of portal areas, occasional islands of residual hepatocytes, and brisk bile ductular proliferation. These cases showed very mild elastosis. Other cases (n = 10) showed little or no ductular proliferation but had increased levels of elastosis. More advanced lesions (n = 3) were composed almost solely of elastosis with small scattered islands of unremarkable hepatocytes, whereas an end-stage lesion (n = 1) was a discrete nodule of fibrosis. In conclusion, segmental atrophy of the liver is typically subcapsular, and is strongly associated with vascular injury. The lesion has multiple stages ranging from parenchymal collapse, to nodular elastosis, to nodular fibrosis. Recognizing the various morphologies will aid in proper diagnosis.     

Angiographically occult arteriovenous malformations

Eight cases of histopathologically proven arteriovenous malformations (AVM's) which were not visualized on angiography are presented. As is typical with these lesions, most of the patients in this series presented with hemorrhage, seizures, or episodic or progressive neurological symptoms suggestive of a neoplasm. The diagnosis of angiographically occult AVM was highly suspected preoperatively in each case based on the combination of computerized tomography (CT) and magnetic resonance (MR) findings. The CT scans in all cases showed moderately hyperdense lesions which enhanced mildly or moderately in a nonhomogeneous pattern with administration of contrast material. The MR image showed one or more bright areas interspersed with areas of low or absent signal peripherally or centrally on both T1- and T2-weighted images. The AVM was totally excised in seven patients and partially excised in one patient, with favorable results in all. The clinical management and differential diagnosis of angiographically occult AVM's are discussed. In patients with a clinical course and radiological studies suggestive of an occult AVM, removal of the lesion, if accessible, should be performed in order to rule out a neoplasm and prevent subsequent hemorrhage and progression of symptoms.