4.. Pathol 1991;95:511-6
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Letters to the Editor 531 J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.61.5.531 on 1 November 1996. Downloaded from tumour was removed with an ultrasonic intervening areas were mostly spindle tumour arising from a single nerve root m aspirator. A thin layer of tumour remained shaped and had a more bulky eosinophilic the lower cauda equina.4 In that case the attached to the conus. A good plane of dis- cytoplasm. Both components stained posi- tumour was completely excised. In the pre- section between the tumour and the surface tively for S-100 protein (figure, d). sent case complete excision was not possible of the conus could not be safely achieved. Electron microscopy showed that the due to adherence to the conus and multiple Postoperatively, she made a slow but tumour cells in the myxomatous nodules nerve roots. The early postoperative course steady recovery. She was relieved of low and those in the internodular areas had has, however, been satisfactory with relief of back and radicular pain. At follow up four elongated cytoplasmic processes, mostly pain and restoration of ambulation. months after surgery, there was an area of covered by a continuous external lamina. The MRI appearance is similar to that of numbness in the L4 dermatome on the Wide spaced collagen fibres (Luse bodies) other intrathecal extramedullary tumours. right. She had returned home, where she were also identified. Ependymoma, neurofibroma, and menin- looked after herself. Neurothekeomas most often occur in the gioma were the major differential diagnoses. The tumour specimen was an irregular, skin of the face and arms of young adults. Connective tissue myxomas have occa- soft, greyish portion of tissue 2-2 x 1-5 x They arise from small cutaneous nerve sionally been described as arising from 0 7 cm in size. Microscopically it displayed a branches and not from the major peripheral paraspinal muscle5 and from the vicinity of a multinodular structure, in which pale, nerves. They are benign lesions which are facet joint.6 An intramedullary location has sparsely cellular islands were separated by cured by excision. Rare recurrences have also been described.7 The compact cellular connective tissue septa or bands of more been reported after incomplete resection. schwannomatous component, the positive compactly cellular neoplastic tissue (figure, Cutaneous neurothekeomas have been clas- staining for S-100 protein, and the ultra- c). The pale nodules had a myxomatous sified into cellular and myxomatous sub- structural appearances clearly distinguish the appearance composed of stellate or elon- types, the second arising at an older age.3 present tumour from connective tissue myx- gated cells in a strongly alcianophilic, Neurothekeomas have rarely been found oma. mucoid matrix. The tumour cells in the intrathecally. There is one report of the GEORGE F KAAR SAAD H BASHIR JAMES M N'DOW Department ofNeurosurgery PHILIP V BEST Department ofPathology LESLEY N GOMERSALL Department ofRadiology, Aberdeen Royal Hospitals NHS Trust, Aberdeen AB9 2ZB, UK Correspondence to: Mr G F Kaar, Ward 40, Aberdeen Royal Infirmary, Foresterhill, Aberdeen AB9 2ZB, UK. 1 Webb JN. The histogenesis of nerve sheath myxoma: report of a case with electron microscopy. jPathol 1979;127:35-7. 2 Angervall L, Kindblom LG, Haglid K. Dermal nerve sheath myxoma. A light and electron microscopic, histochemical, and immunohis- tochemical study. Cancer 1984;53: 1752-9. 3 Barnhill RL, Mihm MC Jr. Cellular neu- at, y J rothekeoma. A distinctive variant of neu- rothekeoma mimicking melanocytic X %. tumours. Am J Surg Pathol 1990;14: 113-5. -i ...4 4 Paulus W, Jellinger K, Pemeczky G. Intra- spinal neurothekeoma (nerve sheath myx- oma). A report of two cases. Am J Clin 4.. Pathol 1991;95:511-6. bV... 5 Tahmouresie A, Farmer PM, Stokes N. Paraspinal myxoma with spinal cord com- POST GA0ODIA1341UDEr pression. Case report. J7 Neurosurg 1981;54: 542-4. http://jnnp.bmj.com/ 6 Bell WO, Gill A, Babiak T, et al. Epidural # myxoma causing compression of the cauda equina. Case report. Neurosurgery 1983;12: i 325-6. ,.l 7 Pasaoglu A, Patiroglu TE, Orhon C, Yildizhan A. Cervical spinal intramedullary myxoma in childhood. Case report. J Neurosurg AN» 1988;69:772-4. on September 26, 2021 by guest. Protected copyright. Voluntary facial palsy with a pontine ;* * . .. lesion Emotional voluntary dissociation is not far~~~~~~~~~~~~~~~~~~~ uncommon in patients with central facial palsies.'-3 The neuroanatomical basis of this dissociation is not well understood. A recent '- .. case report in this J3ournal suggested that a pontine stroke could result in unilateral vol- $ jr 441.8$.. ,, untary facial palsy.4 We have recently had the opportunity to study a very similar syn- drome. p,,O. A teacher aged 57 was referred three days '4~~~~~~~~~~~~~~~~~~0 after the onset of progressive neurological symptoms and signs that had included, in order, unsteadiness, dysarthria, dysphagia, and weakness of the right arm, leg, and face. (a) Sagittal T2 weighted MR image (TR = ms, = tumour 4500 TE 130 ms) showing distorting the On admission, the patient was awake, region of the conus (arrow). (b) Postgadodiamide injection Tl weighted MR image (TR = 450 ms, TE = 15 ms), showing tumour (black arrow) displacing conus (white arrow) anteriorly and dysarthric but not aphasic, and had normal laterally. (c) Photomicrograph (haematoxylin and eosin x 10) showing pale myxomatous nodules vision and oculomotor function. He com- separated by narrow septa. (d) Photomicrograph ( x 40) ofthe tumour stained with the plained of impaired swallowing and right immunoperoxidase method to demonstrate S-100 protein. Note the dark (positive) staining in nuclei facial weakness. Neurological examination and cytoplasmic strands. disclosed a right central facial palsy for vol- 532 Letters to the Editor J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.61.5.531 on 1 November 1996. Downloaded from untary innervation. The patient could nei- tary facial movements projects from the lat- ther whistle nor smile on command. By con- eral motor cortex (area 4) via the genu of the trast, the patient had normal emotional internal capsule and the cerebral peduncle to facial expression when smiling or laughing interneurons within the pontine motor facial (fig 1). Voluntary and emotional innervation nucleus which synapse on facial motor neu- of the upper facial muscles were spared on rons. This corticonuclear pathway projects either side, consistent with a central facial bilaterally to neurons that innervate perior- palsy. There was a prominent central hemi- bital and frontal muscles and mainly con- paresis of right arm and leg. Sensory exami- tralaterally to neurons innervating perioral nation was normal. and buccal muscles. As unilateral brain stem Brain MRI showed a single, semilunar lesions in the upper pons cause contralateral lesion of the left pons that was hyperintense voluntary facial paresis (this study and that on T2 weighted images and hypointense on of Topper et a14) the level of crossing of cor- Tl weighted images (fig 2). The lesion was ticonuclear fibres is probably just above or at sharply delineated medially by the pontine the level of the motor facial nucleus. raphe which was slightly bulged to the right The pathways for emotional innervation due to mild oedematous swelling. The lat- of the face are less clear. Reviewing the per- eral border of the lesion was convex and tinent medical literature,' ' we conclude that I-00!MT7 .7 reached the surface of the anterior brain- probably all patients with unilateral emo- stem, sparing the midpontine tegmentum. tional facial palsy had lesions in the con- No additional cerebral lesions were tralateral forebrain. This excludes as possible detected. The involved area corresponds to pathways for emotional facial innervation the territory of the anteromedial and antero- those previously implicated which involve lateral group of the pontine arteries which ipsilateral or bilateral projections and do not are branches derived from the basilar artery. include thalamic and cortical centres: (a) The localisation of the lesion is consistent from centromedial amygdala and bed with an affection of the corticonuclear and nucleus of stria terminalis via stria terminalis corticospinal tracts, pontine nuclei, and or ventral amygdalofugal projection to hypo- pontocerebellar fibres as well as the medial thalamic preoptic region or mamillary lemniscus on the midpontine level. nuclei, on to ipsilateral motor facial nucleus A voluntary unilateral facial palsy with through the brain stem reticular formation intact emotional expression may result from via dorsal longitudinal fascicle or median lesions of the motor cortex or corticonuclear forebrain bundle;68 10 (b) directly from the tract. An emotional facial palsy with pre- amygdaloid complex to the lateral reticular served voluntary facial innervation has been formation in the ipsilateral pontine tegmen- associated with lesions in the basal ganglia, tum, which in turn innervates the ipsilateral Figure 2 Detection of a single left paramedian thalamus, temporal lobes, frontal white facial motor nucleus." 13 By contrast, we midpontine ischaemic lesion by MRI (1-5 matter, or supplementary motor cortex.' think that emotional facial innervation origi- Tesla, fast spin echo sequence) four days after Bilateral voluntary facial palsy with preserved nates in the amygdaloid complex and associ- the onset ofsymptoms. (A) axial T2 weighted emotional expression is typical of the Foix-