MR imaging in aneurysmal bone cyst of the orbit

Aneurysmal bone cyst is a benign fibro-osseous lesion usually described in the long bones. Intraorbital aneurysmal bone cyst is a rare clinical entity with an entirely different outcome and prognosis as compared to the usual pediatric orbital tumors. The authors report magnetic resonance imaging (MRI) features of an orbital mass lesion in a 4-year-old child who presented with painless proptosis of right eye. Characteristic MRI findings led to a suspicion of an aneurysmal bone cyst that was totally excised via a right frontotemporal craniotomy. Appreciation of characteristic MRI features can be of extreme help for appropriate diagnosis and management of this rare entity.     

A huge occipital osteoblastoma accompanied with aneurysmal bone cyst in the posterior cranial fossa

Osteoblastoma is an infrequent benign tumor and skull involvement is extremely rare. The occipital bone is much less frequently involved. We report an unusual case of a huge occipital osteoblastoma with aneurysmal bone cyst in the posterior cranial fossa of a 20-year-old young man. MRI scan and CT three-dimensional reconstruction revealed that the tumor (approximately 8.5 cm x 6 cm x 5 cm) occupied nearly half volume of the posterior cranial fossa. The cerebellum, the forth ventricle and brain stem were compressed remarkably and hydrocephalus was noted. The tumor mass was multiloculated cystic and highly vascular. Excessive bleeding occurred during operation and total removal was achieved. The patient was symptom-free and MRI scan revealed no evidence of recrudescence after a follow-up period of 18 months. Pathological examination revealed that the lesion was a benign osteoblastoma with secondary aneurysmal bone cyst (ABC). ABC constitutes a highly vascular lesion while complete surgical resection is often impeded by excessive intraoperative bleeding. Preoperative embolization may reduce the risk. Despite the benign nature of osteoblastoma, local recurrence after incomplete resection is not rare and malignant transformation during recurrence may occur even after adequate surgery. Our case confirms the findings of previous investigators that if osteoblastoma is removed completely, no recurrence is expected even without adjuvant irradiation and chemotherapy.     

Recurrent arachnoid cyst of Meckel's cave mimicking a brain stem ischaemia. Report of a rare case

A 44-years old man developed TIA-like symptoms with dysaesthesia around the mouth, vertigo and diplopia. MRI revealed a cystic space-occupying lesion on the right Meckel's cave, which spread out into cerebellopontine angle in a further examination. Therefore surgical exploration was performed using a suboccipital approach. An arachnoidal cyst was found and removed including its wall. About three months later the patient suffered again from dysaesthesias of the right side of the face and a new MRI revealed a recurrence of the lesion, with extension into the cerebellopontine angle, too. Surgical revision was done using the same approach and the recurrent cyst was removed. Postoperatively, there were a transient hypaesthesia in the distribution area of the right trigeminal nerve and a light pulmonary embolism occurred as a complication. No symptoms have returned during an observation period of 15 months. CONCLUSION: An arachnoidal cyst must be considered as a rare cause, when a lesion is found at the Meckel's cave with intermittent clinical symptoms of a trigeminal nerve affection. As surgical treatment we favour fenestration and cyst wall resection.     

Giant epidermoid cyst of the skull with extra and intracranial extension. A case report

Intradiploic epidermoid cyst of the skull is a rare clinical entity that can exceptionally grow to a large size with intracranial extension. The authors report the case of a 38-year-old man with a giant epidermoid cyst of the parietal bone with extra and intracranial extension, presenting with focal neurological symptoms. The diagnosis was suggested at imaging (skull radiographs, CT and MRI), and confirmed at histology. Complete removal of the cyst and its capsule was performed followed by cranioplasty. Postoperatively, the patient was discharged free of symptoms. CT scan provides good evaluation of the bony lesion and may suggest intracranial extension. MRI is superior for evaluation of cerebral compression. The pathogenesis, clinical presentation, diagnostic evaluation and therapeutic management of these rare lesions are reviewed.     

Intracranial aneurysmal bone cyst manifesting as a cerebellar mass

A 17-year-old boy presented with symptoms of raised intracranial pressure for a month. Investigations revealed a large extra-cerebellar mass. The lesion was radically resected. It arose from the petrous bone. Histology revealed that the lesion was an aneurysmal bone cyst [ABC].     

"Tram-track" sign and "donut configuration" in Tolosa-Hunt syndrome]

We report unique MRI abnormalities seen in a patient with Tolosa-Hunt syndrome (THS). A 60-year-old woman was admitted for left eye symptoms, including periorbital pain, numbness around the left eyebrow, blurred vision, delayed light reflex and impairment of abduction. Laboratory studies were unremarkable except for elevated erythrocyte sedimentation rates. T1-weighted MRI showed a mass lesion in the left orbital apex. Fat-suppressed T2-weighted MRI showed a hyperintense parallel linear lesion on the left optic nerve and a ring lesion around it, producing the "tram-track" sign on the axial view and the "donut configuration" on the coronal view. A diagnosis of THS was made, and corticosteroid therapy was started. Symptoms were improved rapidly, and MRI abnormalities disappeared. Reevaluation of MRI which had been taken at the previous episode of the right eye symptoms two years before also showed the "tram-track" sign and the "donut configuration" on the right. These signs are easy to be recognized and well reflect the stage of the disease. They are thus useful for diagnosing THS and evaluating the effect of the treatment. One should pay attention not only to the cavernous sinus and orbital apex, but also to the optic nerve for the MRI diagnosis of THS.     

Displasia fibrosa craneofacial y quiste óseo aneurismático en una paciente con síndrome de McCune-Albright. Presentación de un caso y revisión de la literatura

McCune-Albright syndrome (MAS) is a rare heterogeneous genetic disorder that is characterized by a triad of polyostotic fibrous dysplasia (FD), café au lait spots (CAL), and multiple hyperfunctional endocrinopathies. In general, it is diagnosed clinically. From the triads, 2 of the findings are enough to make the diagnosis.Craniofacial fibrous dysplasia is a term that is used to describe the fibrous dysplasia, which was localized at the craniofacial skeleton and is common in MAS patients.Aneurysmal bone cyst (ABC) is a rare non-neoplastic bone lesion that involves mostly the long bones and vertebrae and may occur very rarely in the craniofacial bones. ABCs may occur as secondary bony pathologies in association with various benign and malignant bone tumors and with fibrous dysplasia. Secondary ABC occurring in craniofacial FD is extremely rare. We present the case of a 21-year-old patient treated at our center for a right orbital aneurysmal bone cyst associated with MAS and provide a review of the relevant literature.     

A case of cystic metastatic intracranial amelanotic melanoma--analysis of findings in CT and MRI

A case of cystic intracranial metastatic amelanotic melanoma is presented. As far as we know, cyst formation in intracranial melanoma is rare, and only 15 cases of intracranial amelanotic melanoma have been reported until now. A 63-year-old man was admitted with headache and progressive visual disturbance. CT scan revealed a large low-density mass with ring-like enhancement in the left frontal lobe. Both T 1-and T 2-weighted MRI images revealed hyperintensity. A left frontotemporal craniotomy was performed. A yellowish mass was observed in the frontal lobe. The content of the cyst consisted of old hematoma, xanthochromic fluid and necrotic tissue, was evacuated and the cyst wall was totally resected. No abnormal pigmentation was noted in the cyst wall and surrounding brain tissue. The histological examination revealed amelanotic melanoma. Primary lesion was found on the left thigh later and resected. The patient died of further intracranial metastasis with repeated hemorrhage 5 months after the admission. Both CT and MRI findings of our case is atypical as an intracranial malignant melanoma. However, these are compatible with those of intracerebral hemorrhage in subacute stage. It is suggested that melanoma may make the diagnosis difficult when tumor hemorrhage modifies the images of CT or MRI.     

Cystic Giant Sacral Schwannoma Mimicking Aneurysmal Bone Cyst : A Case Report and Review of Literatures

To present a rare case of a cystic giant schwannoma of the sacrum mimicking aneurysmal bone cyst (ABC). A 54-year-old man visited our institute complaining left leg weakness and sensory change for several years. Magnetic resonance imaging revealed a large multilocular cystic mass with canal invasion and bone erosion confined to left S1 body. The lesion showed multiple septal enhancement without definite solid component. Initially the tumor was considered as ABC. The patient underwent grossly-total tumor resection with lumbosacral reconstruction via posterior approach. The tumor was proved to be a cystic schwannoma. The postoperative course was uneventful and the patient was relieved from preoperative symptoms. We present a rare case of pure cystic giant schwannoma confined to sacrum mimicking ABC. The surgical treatment is challenging due to the complex anatomy of the sacrum. Schwannoma should be considered in the differential diagnosis of osteolytic sacral cysts.     

A case of Tolosa-Hunt syndrome starting from abducens nerve palsy alone]

A 59-year-old man was admitted to our hospital because of right abducens nerve palsy without orbital pain. One month later right orbital pain appeared and two months later the pain changed to an aching severe pain and the right oculomotor, trochlear and trigeminal nerves were also involved. The administration of corticosteroid dramatically reduced these symptoms. The diagnosis was Tolosa-Hunt syndrome (THS) based on these findings. THS starting with abducens nerve palsy alone is rare, representing only 5.1% of 118 patients. In our patient, the newly developed dynamic MRI was able to reveal the right cavernous sinus lesion. The diagnostic usefulness of dynamic MRI for cavernous sinus lesions has been demonstrated for such cases.     

Recurrent orbitofrontal cholesterol granuloma in pediatric patient: case report and review of the literature

Orbitofrontal cholesterol granuloma is a rare entity which typically involves the lateral part of the supraorbital ridge. It causes progressive expansion and erosion of the inner and outer tables of the frontal bone. We describe a case of recurrent orbitofrontal cholesterol granuloma in a 17-year-old girl. In June 2002 this patient had originally presented to an eye clinic with a small palpable mass in the right superolateral orbit, limitation on upgaze, and progressive proptosis. MRI of the orbit revealed an intraorbital extraconal mass with smooth border, high signal on both T1- and T2-weighted magnetic resonance images. She underwent an anterior orbitotomy via a subbrow incision. The lesion was removed completely, and histopathological examination confirmed a cholesterol granuloma. She remained asymptomatic until her presentation in August 2005. On second admission (3 years later), she complained of a tender palpable mass in the superolateral aspect of the right orbit. Her right eye was 4 mm proptosed and 4 mm inferomedially displaced with limited elevation. The rest of the examination was normal. MRI of the orbit showed a large intraorbital but extraconal mass with smooth border, high signal on both T1- and T2-weighted images without enhancement after gadolinium injection. She underwent complete surgical excision by means of a bicoronal approach. Histopathological diagnosis revealed cholesterol granuloma. No recurrence of the lesion has been observed during the last 6 years following the second operation.     

A rare bone–leptomeningeal metastasis from an adrenal cortical carcinoma

We report a rare bone–leptomeningeal metastasis from an adrenal cortical carcinoma (ACC). ACC is a rare malignancy and represents one of the most unusual sources of intracranial metastases (0–0.2%); the localization to the skull bone and meninges is uncommon. A 45-year-old man underwent surgery for a non-functioning ACC; 4 months later he developed a soft left frontal mass. The CT scans and MRI showed a large tumor with bone and leptomeningeal involvement. Despite chemotherapy, the lesion increased in volume, which led to local pain and right hemiparesis. Thus, the patient underwent excision of the mass; histopathological diagnosis confirmed that it was an ACC metastasis. The patient underwent standard radiation therapy after surgery. At post-operative follow-up, the patient was in a good neurological condition with no radiological evidence of a cranial recurrence; however, there was a voluminous abdominal regrowth of the primary tumor. To our knowledge, this is the second case of bone and leptomeningeal metastasis arising from an ACC. This patient report confirms the effectiveness of aggressive surgery for management of large intracranial metastases, particularly those that arise from primary tumors that are resistant to radiotherapy and chemotherapy. In our opinion, surgery represents the most appropriate treatment for voluminous intracranial metastasis – even when there are no neurological signs.     

Giant intradiploic epidermoid cyst of the occipital bone

A rare case of giant intradiploic epidermoid cyst of the occipital bone with large intracranial extension in the posterior fossa is described. The lesion was discovered when the patient presented with headache and subcutaneous swelling in the occipital region, in the absence of signs of neurological involvement. CT scan showed extensive destruction of the occipital bone, mainly of the inner table, up to the foramen magnum. On MRI the lesion was hypointense in T(1) and hyperintense in T(2)-weighted images; signal inhomogeneity was due to cellular debris and cholesterol crystals. The enhancing rim due to the thickened dura confirmed the extradural location. Complete removal of the cyst was easily accomplished despite its large size. We found only 3 documented cases in the literature of giant intradiploic infratentorial epidermoid cysts, none of which was studied by MRI. The radiological features and differential diagnosis are discussed.     

Spontaneous Intraorbital Hemorrhage : A Case Report

Intraorbital hemorrhage is a rare clinical condition caused by orbital trauma, surgery around the orbit, intraorbital vascular abnormalities, and neoplasm. It was reported to occur spontaneously without any known causes and in association with orbital pseudotumor in a very few cases. A 59-year-old, female patient admitted with sudden onset of severe exophthalmos and pain on the left eye. Orbital CT and MR imaging suggested hemorrhage in the upper part of retrobulbar area of the left orbit. Cerebral angiography was taken to rule out any possible vascular abnormalities. On the left carotid cerebral angiography, the run-off of the distal ophthalmic artery was not seen and the engorgement of the supraophthalmic artery was noted. Systemic administration of corticosteroid did not improve the clinical status and craniectomy was done and retrobulbar hematoma was removed, and the clinical symptoms and signs were improved. Authors report a case of spontaneous intraorbital hemorrhage with the clinical features similar to those of orbital pseudotumor, requiring surgical decompression.     

Orbital Solitary Fibrous Tumor : A Case Report and Diagnostic Clues

Orbital solitary fibrous tumor (SFT) is a rare tumor originating from the mesenchyme. We describe the clinical presentations, radiological and operative findings, and pathological features of a patient with orbital SFT. The patient was a 46-year-old female who presented with progressive proptosis advanced for 20 months. On ophthalmological examination, no visual impairment was detected, but left eye was found to be obviously protruded on exophthalmometry. Orbital magnetic resonance imaging showed a 2.5 × 2 × 2 cm, intensely enhanced mass in the left orbit, which compressed the eyeball forward and the optic nerve downward. The patient underwent frontal craniotomy with superior orbitotomy and gross total resection was performed for the tumor. The histopathological diagnosis including immunohistochemistry was a SFT. After the surgery, proptosis was markedly relieved without visual impairment. Although orbital SFT is extremely rare, it should be considered in the differential diagnosis of orbital tumors. Clinical presentations such as painless proptosis and CD34 immunoreactivity play a significant role in differentiating orbital SFT from other spindle-cell neoplasms of the orbit.     

Dermoid cyst of the posterior fossa

Intracranial dermoid tumors represent a rare clinical entity accounting for 0.1-0.7% of all intracranial tumors. Their location in the posterior fossa is uncommon. We report a 16-year-old male patient who presented with clinical signs of increased intracranial pressure and cerebellar symptoms. The CT scan revealed a median cystic lesion of the fourth ventricle causing an active triventicular hydrocephalus. The MRI showed a median well shaped cystic lesion, of low signal intensity compared to the CSF, with capsular contrast enhancement. He underwent endoscopic third ventriculostomy before subtotal removal of the lesion. The postoperative course was uneventful, and the histological diagnosis was a dermoid cyst. Through this observation, we aim to discuss the clinical, and radiological aspects of the posterior fossa dermoid cyst, and to review the therapeutic strategies.     

Intracavernous sinus arachnoid cyst with optic neuropathy

An 18-year-old man experienced progressive decreased visual acuity associated with a redness of the right eye for 1 month. An arachnoid cyst was identified within the right cavernous sinus and fenestration to the basal cistern was performed with the aid of a neuroendoscope. Visual acuity improved dramatically after the operation. Intracavernous sinus arachnoid cyst is a rare congenital intracranial lesion and surgical decompression may benefit symptomatic patients.     

Spontaneous regression of an epidermoid cyst of the cavernous sinus

Epidermoid cysts are rare lesions in the pediatric population. The natural history of epidermoids is usually that of slow growth, although rupture and cases of malignant transformation have been reported. Spontaneous regression of an intracranial epidermoid cyst has not previously been described to our knowledge. We present a 3-year-old boy who presented with severe vertigo. MRI was performed which revealed a 2 cm non-enhancing lesion in the right cavernous sinus. The lesion was T1-hypoinsense, T2-hyperintense, and with evidence of restricted diffusion, consistent with an epidermoid cyst. The patient was followed with annual MRI studies over the next 3 years, demonstrating progressive reduction in the size of the lesion over time, with complete resolution after 3 years. The child’s symptoms also resolved during this period. Long-term follow-up imaging at 5 years showed no evident lesion. To our knowledge, this is the first report documenting spontaneous regression of an intracranial epidermoid cyst. While isolated, this finding demonstrates the potential for involution of epidermoids and lends support to the clinical practice of careful observation of these lesions, especially when located in areas associated with high potential surgical morbidity. Importantly, the novelty of this observation suggests a need for further study to better elucidate the underlying mechanism of this regression.     

Painless orbital myositis

Idiopathic orbital inflammation is the third most common orbital disease, following Graves orbitopathy and lymphoproliferative diseases. We present a 11 year old girl with 15 days history of painless diplopia. There was no history of fluctuation of symptoms, drooping of eye lids or diminished vision. She had near total restricted extra-ocular movements and mild proptosis of the right eye. There was no conjunctival injection, chemosis, or bulb pain. There was no eyelid retraction or lid lag. Rest of the neurological examination was unremarkable.Erythrocyte sedimentation rate was raised with eosinophilia. Antinuclear antibodies were positive. Liver, renal and thyroid functions were normal. Antithyroid, double stranded deoxyribonucleic acid and acetylcholine receptor antibodies were negative. Repetitive nerve stimulation was negative. Magnetic resonance imaging (MRI) of the orbit was typical of orbital myositis. The patient responded to oral steroids. Orbital myositis can present as painless diplopia. MRI of orbit is diagnostic in orbital myositis.     

Meningitis Complicating an Occult Infected Nasal Epidermoid Cyst in a Child

Congenital nasal epidermoid cyst without associated facial dysmorphism is an uncommon anomaly that is often asymptomatic. We report a case of occult nasal epidermoid cyst in a 12-year-old boy with initial nonspecific symptoms of fever, headache, abdominal pain, vomiting, and diarrhea. An enhanced magnetic resonance imaging (MRI) showed a cystic lesion in the frontal skull base with expansion of the foramen cecum and the perpendicular plate of the ethmoid bone, accompanied with meningitis. An emergent surgical intervention was undertaken, and an infected epidermoid cyst was confirmed by pathology. He recovered uneventfully during a 4-week treatment with parentally-administered antibiotics. This significant case report demonstrates the importance of MRI in the early diagnosis of a life-threatening intracranial infection from an otherwise occult infected congenital nasal epidermoid cyst in children.