Thorax 1993;48:298-299

Short reports

Intrathoracic vagus

nerve neurofibroma andsudden death in a

patient withneurofibromatosis

L Tsun-Cheung Chow,B Shui-Fung Shum, Wing-Hing Chow

AbstractA 21 year old man with type 1 neuro-

fibromatosis was found dead in themiddle of the night. Postmortemexamination revealed a large neurofibro-ma arising from the right intrathoracicvagus nerve, which might have con-

tributed to his sudden death.

(Thorax 1993;48:298-299)

Neurofibromas are benign tumours of theperipheral nerves usually presenting as palp-able masses in the subcutaneous soft tissue.In type 1 neurofibromatosis they may befound in almost any location and present withunusual symptoms. I In this report we

describe the sudden death of a patient withtype 1 neurofibromatosis who was found tohave a neurofibroma of the intrathoracicvagus nerve.

Institute of Pathology,Queen ElizabethHospital, Kowloon,Hong KongL Tsun-Cheung ChowForensic PathologyService, Departmentof Health, Hong KongB Shui-Fung ShumDepartment ofMedicine, GranthamHospital, Aberdeen,Hong KongWing-Hing ChowReprint requests to:Dr L T-C Chow

Received 3 February 1992Returned to authors30 March 1992Revised version received1 May 1992Accepted 7 May 1992

Case reportA 21 year old man with type 1 neurofibro-matosis had been followed up in our out-patient clinic. He had initially presented fiveyears earlier with multiple cafe au lait spotsand cutaneous neurofibromas and radiologi-cal examination of the chest and spinerevealed mild thoracolumbar scoliosis. Nomass was detected in the mediastinum. Asthe scoliosis was mild and showed no evi-dence of progression, surgery was not carriedout. Since then, no further radiological exam-

ination of the chest had been undertaken. Hehad remained well and was last seen seven

months before being found dead in his bed inthe middle of the night.On postmortem examination the main

findings were in the thoracic cavity. Therewas mild thoracolumbar scoliosis with con-

vexity to the left. A huge neurofibroma,17 x 10 x 9 cm, was seen arising from theright vagus nerve. It extended from the originof the right recurrent laryngeal nerve to 1 cm

below the cavoatrial junction (fig 1). Theheart and trachea were slightly displaced to

Figure 1 Gross specimen including the tongue (T) andsuperior portions of the larynx and hypopharynx. A largeneurofibroma (N) is seen arisingfrom the rightintrathoracic vagus nerve. Multiple small neurofibromasare seen along the length of both recurrent laryngeal nervesas fusiform swellings.

the left but retained their normal contours.There was no appreciable compression of themajor vessels. Multiple small neurofibromaswere present along the entire length of bothvagus and recurrent laryngeal nerves (fig 1).Cut section of the large neurofibroma showedpale yellow firm tissue. Microscopy revealedcharacteristic features of neurofibroma, con-sisting of wavy spindle tumour cells support-ed in a loose myxoid stroma in which were anumber of mast cells (fig 2A,B). Immuno-histochemically the tumour cells showedintense positive staining for S-i 00 protein (fig2B), confirming their neural differentiation.The heart weighed 300 g and was normal.

The coronary vessels were widely patent andthere was no acute myocardial infarction. Thecardiac conduction system appeared normalon histological examination and the othercranial nerves and both adrenal glands werenormal. There was no evidence of phaeo-chromocytoma. The other organs showednothing noteworthy.

DiscussionThe neurofibromatoses are genetic disordersthat primarily affect cell growth of neural tis-sues. Two clinically and genetically distinctforms are recognised: type 1 or peripheral

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Intrathoracic vagus nerve neurofibroma and sudden death in a patient with neurofibromatosis

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Figure 2 (A) Photomicrograph of the neurofibroma showing wavy spindle tumour cellssupported in a myxoid stroma (haematoxylin and eosin). (B) The tumour cells showingintense positive immunostainingfor S-100 protein.

neurofibromatosis and type 2 or centralneurofibromatosis.3 In type 1 neurofibromasmay be found in virtually any location' andunusual symptoms have been related to thepresence of these tumours in various organs

including the gastrointestinal tract," appen-

dix,7 larynx,8 blood vessels,9 and heart.'0Our patient showed classical clinical

features of type 1 neurofibromatosis withmultiple cafe au lait spots, cutaneous neurofi-bromas, and thoracolumbar scoliosis. Inaddition, there were multiple neurofibromasof both vagus and recurrent laryngeal nerves,

the one affecting the right intrathoracic vagus

nerve assuming an unusually large size (fig 1).In this respect it is interesting to note thatneurogenic tumours of the vagus nerves,

including neurofibromas and schwannomas,have a predilection for the left side." 12

Dabir et al"2 suggest that this could be due to

the propensity of these tumours to occur inthe thickest portion of the nerve-hence the

tendency to arise on the left proximalintrathoracic vagal trunk, which is larger thanthat on the right side.The sudden death of this patient is unique

and of interest. The exact cause is not known,but, in the absence of significant findings inthe clinical background of type 1 neurofibro-matosis apart from the large neurofibroma ofthe right intrathoracic vagus nerve, it istempting to relate death to the neurofibroma.Associated phaeochromocytoma dischargingarrhythmogenic catecholamines is not thecause in our case as postmortem examinationrevealed no evidence of either adrenal orextra-adrenal phaeochromocytoma. The pos-sibility that the carotid sinus syndrome con-tributed to his death is unlikely as themediastinal neurofibroma was located faraway from the carotid sinus and the glosso-pharyngeal nerve itself was unaffected bytumour. The exact posture of the patientwhen he was found dead in his bed could notbe recalled by his parents. If he had beenlying in a left lateral position, the mechanicaleffect on the heart and great vessels of thelarge tumour on the right intrathoracic vagusnerve could have contributed to his suddendeath. This is not substantiated, however, bythe findings of the postmortem examinationas the heart retained its normal contour andthere was no appreciable compression of themajor vessels. Finally, the neurofibromamight have resulted in autonomic dysfunctionleading to cardiac arrhythmia and suddendeath.The sudden death of this patient suggests

that patients with type 1 neurofibromatosisshould have regular radiographic chest exami-nations as early detection and treatment ofneurofibromas of the intrathoracic vagusnerve may be desirable.

We thank Miss Cindy L K Lau for her expert secretarialassistance.

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