Imaging Features of Hypertrophic Olivary Degeneration.

Hypertrophic olivary degeneration (HOD) is a unique form of transneuronal degeneration caused by a disruption of the dentato-rubro-olivary pathway, also known as the triangle of Guillain-Mollaret. The triangle of Guillain-Mollaret is involved in fine voluntary motor control and consists of both the inferior olivary nucleus and the red nucleus on one side and the contralateral dentate nucleus. Clinically, patients classically present with symptomatic palatal myoclonus. Typical magnetic resonance imaging findings include T2-hyperintensity and enlargement of the inferior olivary nucleus evolving over time to atrophy with residual T2-hyperintensity. In this article, we provide a case-based illustration of the anatomy of the Guillain-Mollaret-triangle and the typical imaging findings of hypertrophic olivary degeneration.

The simultaneous appearance of a nasal natural killer-cell lymphoma and acute myelogenous leukemia.

INTRODUCTION AND AIM: Sinonasal malignant neoplasms are uncommon, with an annual incidence of less than 1/100,000. About 80% of these are squamous cell carcinoma. Adenocarcinoma and adenoid cystic carcinoma are next in frequency. Lymphoma of the nasal cavity, paranasal sinuses and nasopharynx are rare, constituting less than 5% of all extranodal lymphomas. CASE REPORT: A 47-year-old man was referred to our hospital because of severe headache and progressive facial pain. He also complained of right-sided visual acuity. He had a manifest exopthalmia with disturbed eye movements. Nasoscopy showed a large mass with atypical appearance. CT and MRI showed a bilateral ethmoid mass invading the frontal sinuses, the right orbit, the lamina cribrosa and the right frontal cerebral region, and growing posteriorly through the choana. The first biopsies were inconclusive, showing only necrotic cells and purulent inflammation with epithelial elements. A larger biopsy demonstrated a high-grade malignant tumour with necrosis. The differential diagnosis of undifferentiated sinonasal carcinoma, undifferentiated neuro-endocrine tumour or T-cell lymphoma was suggested. In the meantime our patient developed high fever and sudden-onset pancytopenia. Bone marrow punction showed 65% blasts, leading to the diagnosis of AML type M2. He was immediately referred for chemotherapy, but died in intensive care before his first session. The biopsy of the sinonasal mass was diagnosed surprisingly as a natural killer cell lymphoma stage IVB. CONCLUSIONS: Natural killer cell lymphoma is rare in Europe. The simultaneous appearance of a NK-cell lymphoma and acute myelogenous leukemia has, as far as we know, never been described in the English literature before.

Radiological findings in a rare case of eyelid swelling: Pott's puffy tumor.

Pott's puffy tumor (PPT), or osteomyelitis of the frontal bone, is a rare entity especially in adults. PPT is believed to occur as a complication of fronto-ethmoidal sinusitis or trauma to the frontal bone. We present the computed tomography and magnetic resonance imaging findings in such a rare case of Pott's puffy tumor.

CT and MR findings in a neuroforaminal extraskeletal Ewing sarcoma mimicking benign nerve sheath tumor.

INTRODUCTION: We report the CT and MR findings in a 30-year-old man with extraskeletal Ewing sarcoma (EES) involving the left neural foramen at L5-S1 level. MATERIALS AND METHODS: The patient was evaluated with preoperative lumbosacral CT and MR imaging and postoperative lumbosacral MR imaging. RESULTS: The lesion was hyperdense on CT, isointense on T1- and T2-weighted MR images, and enhanced homogeneously after intravenous gadolinium injection. With these CT and MR findings, surgery was performed with a presumptive diagnosis of nerve sheath tumor, but the histopathological examination revealed EES. Chemotherapy and radiotherapy were planned postoperatively. CONCLUSION: This case illustrates that even in benign looking lesions in a neuroforamen one can never exclude malignancy, and this is even more true in a population of young adults.

MRI findings in giant pontine capillary telangiectasis associated with a developmental venous anomaly.

We report a 32-year-old woman with an exceptionally large capillary telangiectasia in the brainstem which is associated with a developmental venous anomaly (DVA). Her major problems were nystagmus in both eyes, binocular diplopia, gait abnormalities, cerebellar ataxia, slightly disturbed finger-nose test, an instable Romberg test and obvious dysartria. The diagnosis was made on the basis of specific imaging findings, and the use of gradient echo-weighted images proved to be helpful in making a differential diagnostic decision.

Incidental radiological finding of a renal tumour leading to the diagnosis of Birt-Hogg-Dube syndrome.

Birt-Hogg-Dubé (BHD) syndrome is a rare autosomal dominant condition characterised by benign tumours of the hair follicle, renal cancer, pulmonary cysts and spontaneous pneumothorax. We report the diagnosis of a BHD syndrome achieved after incidental radiological finding of a renal tumour in a 24-year old man. The patient also displayed recurrent pneumothoraces and showed to have cysts in the basis of both lungs. The association of recurrent pneumothoraces and renal neoplastic disease should alert for the possible presence of this syndrome.

Pott's puffy tumor: CT and MRI findings.

Pott's puffy tumor, a subperiosteal abscess of the frontal bone with cranial osteomyelitis, is a rare complication of frontal sinusitis. In this report, we describe the radiological findings of a 24-year-old man, presenting with swelling of the right upper eyelid. Correct and early diagnosis of this infrequent, but potentially life-threatening condition is of utmost importance.

Aryepiglottic fold and subcutaneous metastases from breast carcinoma.

We report the CT findings in a 77-year-old woman with left-sided aryepiglottic fold metastasis from breast cancer diagnosed 7 years previously. The lesion obliterated the left piriform sinus, had a lobulated contour and showed mild and heterogeneous enhancement on a post-contrast CT examination. Biopsy of the lesion revealed metastasis from poorly differentiated adenocarcinoma, compatible with metastasis of the breast carcinoma. Before detection of the laryngeal lesion, a second primary tumor in the right ovary was diagnosed. After right oopherectomy, histopathology revealed clear cell adenocarcinoma. The patient also had multiple subcutaneous metastases and bilateral cervical lymphadenopathies. Chemotherapy was applied to the patient.

CT-imaging of lesser known or seen anatomical structures of the temporal bone.

Temporal bone anatomy is complicated on CT with many normal variants, of which some are infrequently seen or lesser known. The unaware radiologist can confuse them with pathology. Other lesser known normal variations are important to report because they can cause pathology. This paper illustrates in detail how to avoid such misinterpretations of anatomical structures.

Imaging of the opacified middle ear.

Middle ear opacification on imaging studies performed in a non-traumatic setting mostly reflects chronic inflammatory/infectious disease. In some of these patients an underlying cholesteatoma will be found. High-resolution computed tomography examinations and magnetic resonance imaging are often used in the work-out of the disease. High-resolution computed tomography of the opacified middle ear serves to describe the status of the ossicular chain, and its suspensory apparatus, as well as the status of the tympanic and mastoid wall. When ossicular erosions are visualized, the probability of a present cholesteatoma is about 90%. Whereas high-resolution computed tomography is not able to differentiate cholesteatoma from other types of opacification, magnetic resonance imaging is. The combined use of delayed post-Gd T1-weighted images and non-EPI based DWI seems to be the actual best option on this matter.

A dural craniocervical fistula in a patient with progressive cervical myelopathy.

A 47-year-old male patient with a dural craniocervical fistula is presented. One year after a car accident the man was admitted to the emergency department with severe nausea and progressive paralysis of the lower legs. MRI examination of the brain and cervical spine discovered cervical myelopathy and tortuous blood vessels anterior to the pons and cervical medulla. Angiography was performed to provide the final diagnosis of craniocervical fistula. An embolization of the fistula was performed, and all of the patient's complaints disappeared within three days.

MRI findings of the normal and diseased trigeminal nerve ganglion and branches: a pictorial review.

The trigeminal nerve is the largest cranial nerve with both a sensory and motor function. MRI is an excellent technique to evaluate the trigeminal nerve. We report the MRI findings and illustrate the normal and diseased trigeminal nerve at Meckel's cave, the cavernous sinus, the skull base foramina, the pterygopalatine fossa and the peripheral branches.

Devic's neuromyelitis optica: clinical and imaging findings.

Devic's neuromyelitis optica is an uncommon but severe monophasic or relapsing demyelinating disease. Current evidence supports the concept that it is a distinct disorder from multiple sclerosis, with some specific imaging characteristics. The aim of this paper is to report the clinical and imaging features of this rare entity and to discuss its differential diagnosis.