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Case R eport
Ce rvical Thymoma
Head and Neck Service of Heliópolis Hospital (HOSPHEL), São Paulo, Brazil
Abrão Rapoport Claudiane Ferreira Dias João Paulo Aché de Freitas Ricardo Pires de SouzaINTRODUCTION
C e rvic a l thymo ma is a primitive thymic neoplasia. It is very rare, with only 1 8 cases having been reported up to 1 9 9 4 according to a survey of English-language literature, of which 1 6 cases were female.1 This disease presents higher incidence in female patients in their 4 th to 6 th decade of life.2
The thymus is a g land o rig inating fro m the epithelium, which fo rms in the third po rtio n o f the pharynx during the tissue matching that takes place in the sixth week o f fetal life. In the eig hth week o f fetal life there is a mig ratio n o f the thymus fro m the cervical reg io n to wards the caudal and medial reg io n to its final lo catio n at the upper mediastinum. Failure o f this mig ratio n will cause abno rmalities o f thymic tissue such as hypo plasia, cysts, g landular tissue at the periphery o f the thyro id a nd c e rvic a l thymus w ith o r w itho ut mediastinal extensio n.
Thymic tissue with a typic a l lo c a tio n ha s been classified3 into seven types: type 0 , with no c e rvic a l e xte nsio n; typ e 1 , rig ht o r le ft extensio n, witho ut co ntact with the thyro id g land; type 2 , left o r rig ht extensio n in co ntact with thyro id ; typ e 3 , b ila te ra l e xte nsio n w itho ut co ntact with thyro id; type 4 , bilateral extensio n, o ne side in co ntact with thyro id; type 5 , bilateral
ABSTRACT
Contex t: Cervical thymoma is a primitive thymic neoplasia. It is very rare. This disease presents higher incidence in female patients in their 4 th to 6 th decade of life. W e present a case repo rt o f a cervical thymo ma
Ca se Report: 5 4 -year-o ld female patient, caucasian, with no histo ry o f mo rbidity, presenting a left cervical no dule clo se to the thyro id gland. During the 3 0 mo nths o f investig atio n a left cervical no dule g rew pro g ressively next to the thyro id while the patient sho wed no sympto ms, making accurate diag no sis difficult. Tests o n her thyro id functio n did no t sho w chang es, no r were there chang es in any subsidiary tests. The diag no sis o f the disease was made intra-o peratively thrintra-o ug h tintra-o tal thyrintra-o id individualiz atiintra-o n. The results were co nfirmed by the histo lo g ical finding s fro m the ressected material. Cervical thymo ma is a very rare disease, with difficult preo perato ry diag no sis. So me additio nal study metho ds which are emplo yed to day are thallium 2 0 1 , technetium 9 9 and io dine 1 3 1 scintig raphy, mag netic nuclear reso nance and especially
histo patho lo g ical finding s and classificatio n. Uniterm s: N eck. Cervical thymo ma.
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e xte nsio n in c o nta c t w ith thyro id ; typ e 6 , unilateral extensio n, abo ve the thyro id g land; type 7 , disc reet no des a t la tera l po sitio ns in co ntact with the thyro id. Types 3 and 4 are the mo st frequent presentatio ns. The case repo rted here is classified as type 2 thymic tissue.
CASE REPORT
The pa tie nt wa s fe ma le , 5 4 ye a rs o ld, Caucasian, with no histo ry o f mo rbidity, presenting a left cervical no dule clo se to the thyro id gland. O n February 2 4 , 1 9 9 4 , a thyro id scintigram was made that sho wed a no rmal thyro id gland and an extra thyro id no dule, which was diag no sed as benign and was referred fo r co nservative treatment at ano ther institutio n. After two and a half years o f no dule g ro wth, ano ther thyro id scintig ram was pro duced and the repo rt sho wed an enlarg ed thyro id gland (no dular go iter) and a “co ld” cervical no dule, as it was no t po ssible to ascertain whether this was a thyro id no dule by scintigraphy.
During its e vo lutio n the p a tie nt w a s asympto matic and did no t sho w any cervical masses o ther than the o ne repo rted abo ve. Upo n examinatio n o f the no dule, the thyro id tests were no rmal and chest x-rays sho wed no chang es.
O n July 2 1 , 1 9 9 7 , she was submitted to surg ic a l tre a tme nt with to ta l re se c tio n o f the c e rvic a l ma ss in c o nta c t w ith the up p e r mediastinum. After perfo rming a necklace-type incisio n 3 cm abo ve the sternal furcula, the mass w a s o b se rve d in the up p e r me d ia stinum,
pro je c te d to wa rds the supra ste rna l a nd pre -thyro id re g io ns. W e ha d to p e rfo rm b lunt detachment techniques in o rder to free the tumo r, which presented a so lid aspect with a whitish b ro wn c o lo r. The po sto pe ra tive pe rio d wa s uneventful.
Macroscopic examination
The surg ic a l sa mp le w a s no d ula r, measuring 6 .0 cm x 5 .0 cm x 4 .0 cm, lo bulate, whitish bro wn co lo r, hard, wo o dy, co vered by a delicate membrane. At cutting , we o bserved a fasciculated surface, milky co lo r with whitish stria (Fig ure 1 ).
Microscopic examination
The cuts sho wed epithelial and lympho cytic e le me nts unifo rmly sp re a d , w ith a lte rna te p re d o mina nc e . The e xiste nc e o f a tumo r surro und e d b y a c o mp a c t c o nne c tive tissue c a p sule , inte rsp e rse d b y nume ro us p a rtia lly hya liniz e d c o nne c tive se pta w a s c o nfirme d. Ep ithe lia l c e lls p re se nte d c le a r c yto p la sm, vesiculate o vo id nuclei g ro uped in small numbers o f c ells, o r were seen with spa c es a mid the lympho cytes. So me o f these cells ha d mito tic a c tivity. Ho w e ve r, w e d id no t o b se rve a ny atypical cellular element in the material examined (Fig ures 2 and 3 ).
DISCUSSION
Thymic neo plasia takes place predo minantly in the anterio r mediastine and is usually a tumo r
Fig. 1 - Encapsulated nodule with lobulate appearance.
Fig. 2 - Double epithelial and lymphocytic cell popula-tion, with “starry sky” appearance (Hematoxylin Eosine).
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with a slo w gro wth rate.4 ,5 It o ccurs in aro und 5 0 % o f the patients with miastenia gravis and is mo re prevalent in female patients.2
The majo rity o f cervical thymo mas present asympto matic evo lutio n, beco ming painful in the cases where there is lo cal infectio n o r very rapid g ro wth to g ether with dysphag ia. Cervical thymic tissue ma y b e fo und in a b o ut 2 1 to 4 2 % o f children and o ccasio nally it mimics a cervical tumo r.1 There is no repo rt o f an incidence ratio between men and wo men with this disease due to its lo w incidence in male patients.
The case which we present in this paper c o nfirms the c linic a l sta tus repo rted in wo rld literature, with asympto matic histo ry, slo w g ro wth a nd dia g no sis c o nfirmed b y pa tho lo g y. The differential diag no sis between thyro id no dule o r cervical tumo r was made at the intrao perato ry evaluatio n fro m the po sitio n o f the tumo r, its to tal ind ivid ua liz a tio n fro m the thy ro id , its macro sco pic aspect and its relatio nship with the upper mediastinum. The diagno sis was co nfirmed via anato mo patho lo g ical studies.
The larg est study to date was carried o ut in 1 9 8 3 by Yamashita et al6 with 1 2 cases o f cervical thymo mas in a g ro up o f 6 5 7 patients w ith Ba se d o w ’ s d ise a se , b y p e rfo rming histo patho lo gical and epidemio lo gical evaluatio n o f this patho lo g ical entity.
Investigatio n techniques fo r cervical no dules have needed to be altered, especially when tests have been inco nclusive. Vangro ve et al1 repo rted a case in which the diagno sis o f cervical mass
could only be decided on by using histopathological stud y o f the a sp ira tio n b io p sy w ith use o f immuno pero xidase, whereas the initial evaluatio n had suggested lympho cytic chro nic thyro iditis o r malignant lympho ma. N o mo ri et al7 repo rted o n the hetero geneity o f the co mplicated histo lo gy in thymic neo plasia fo r diag no stic purpo ses and specific and precise treatment.
Scintigraphy with thallium 2 0 1 is used fo r the differential diagno sis between thymo ma and thyro id ne o p la sia , a c c o rd ing to Fukud a .8 Technetium 9 9 is used similarly according to Miller.9 W e used radio active io dine with o ur patients.
Ac c o rding to Kiyo sue et a l,3 ma g netic nuclear reso nance sho uld be the examinatio n o f c ho ic e fo r inve stig a ting c e rvic a l ma sse s o r no d ule s, e sp e c ia lly in c a se s w he re the re is c o mmunic a tio n a mo ng suc h e ntitie s a nd the mediastinum, raising the suspicio n o f a cervical thymo ma.
Acco rding to the study perfo rmed by Ho et a l,2 the histo g e ne tic c la ssific a tio n o f thymic epithelial tumo rs is directly related to the patient’s survival rate. Five g ro ups have been repo rted: g ro up 1 : medullar thymo ma and mixed thymo ma (1 0 0 % surviva l o ve r 1 0 ye a rs); g ro up 2 : predo minantly co rtical thymo ma (1 0 0 % survival o ver 1 0 years); g ro up 3 : co rtical thymo ma and w e ll d iffe re ntia te d thymic c a rc ino ma (4 0 % survival o ver 1 0 years); g ro up 4 : o ther thymic carcino mas (3 0 % survival o ver 1 0 years); g ro up 5 : unclasssifiable. The patho lo g ical classificatio n ha s p re d ic tive va lue in e va lua ting the a g g resiveness po tentia l o f these tumo rs4 a nd therefo re the pro g no sis fo r these patients, thus c o ntrib uting to a p p ro p ria te p o st-o p e ra tive tre a tme nt. O ur p a tie nt w a s histo g e nic a lly classified as being g ro up 1 .
O f the different histopathologic classifications for thymomas, none is totally satisfactory. Several stud ie s ha ve fo und no c o rre la tio n b e tw e e n histological type and prognosis, while other studies clearly mention this correlation.
As cervical thymo ma is a rare disease with presurg ical diag no stic difficulties, immuno histo -chemistry pro vides a mo re efficient metho d fo r diagno stic investigatio n and adequate interventio n
Fig. 3 - Detail of the double cell population, with epithelial cells in evidence (Hematoxylin Eosine).
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RESUMO
Contex to: O timo ma cervical é neo plasia primitiva do timo . Sua incidência é muito rara. Esta do ença apresenta maio r incidência em pacientes do sexo feminino , entre a quarta e sexta décadas. Rela to de Ca so: Apresentamo s o caso de uma paciente do sexo feminino , 5 4 ano s, co m timo ma cervical. Durante o perío do de do is ano s e meio de investig ação teve evo lução assinto mática co m crescimento pro g ressivo do nó dulo cervical, pró ximo à tireó ide. A paciente não apresento u alteraçõ es do s exames de função tireo idiana o u do s exames subsidiário s realiz ado s. O diag nó stico de timo ma cervical fo i realiz ado no intra-o perató rio sendo co nclusivo co m o estudo anato mo pato ló g ico da peça retirada. O timo ma cervical é raro , co m difícil diag nó stico pré-o perató rio . Atualmente utiliz a-se méto do s co mplementares para o diag nó stico preciso co mo : a cintilo g rafia co m Tálio 2 0 1 , o Tecnésio 9 9 e o Io do 1 3 1 , além da resso nância nuclear mag nética e, principalmente, realiz ando o estudo e classificação histo pato ló g ica.
in the treatment o f patients with this disease. At present there are no specific markers fo r cervical thymo ma s, b ut studies investig a ting po tentia l markers are pro mising and in the future these may beco me part o f the ro utine tests in patho lo g ical investig atio n o f such tumo rs.
REFERENCES
1. Vangro ve MA, Schimmel M, Atkinso n BF, Evans D, Livo lsi V. Cervical thymo ma masquerading as a so litary thyro id no dule. Inter Acad Cito l 1991;35:431-3.
2. Ho FC, Fu KH, Lam SY, Chiu SW, Cham AC, Hermelink HK. Evalua-tio n o f a histo genic classificaEvalua-tio n o f thymic epithelial tumo urs. His-to patho lo gy 1994;25:21-9.
3. Kyo sue H, Miyake H, Ko matsu H. MRI o f cervical masses o f thymic o rigin. J Co mp Ass To mo g 1994;18:206-8.
4. Murad AM, Katz A. Onco lo gia-Bases clínicas do tratamento . São Paulo : Ed. Ko o gan 1996;156-7.
5. Martin JM, Randhawa G, Temple W J. Cervical thymo ma. Arch Path Lab Med 1986;110:354-7.
6. Yamashita H, Murakamin N, No guchi S, No guchi A, Yo ko yama S, Mo riuchi A, Nakayama I. Cervical thymo ma and incidence o f cervi-cal thymus. Acta Patho l JpN 1983;33:189-94.
7. No mo ri H, Mo rinaga S, Ko bayashi R, Mimura T. Cervical thymic can-cer infiltrating the trachea and thyro id. Eur J Card Surg 1994;8:222-4.
8. Fukuda T, Itam M, Saura H. A case o f thymo ma arising fro m unde-scended thymus. High uptake o f thallium-201 chlo ride. Eur J Nucl Med 1980;5:465-8.
9. Miller JR, Gefter WB, Miller WT. Thymo ma mimicking thyro id mass. Radio lo gy 1992;182:75-6.
Abrã o Ra poport - MD. Co o rdinato r o f the Po st-G raduatio n Co urse in Head and N eck Surg ery o f Helió po lis Ho spital (HO SPHEL), São Paulo , Braz il.
Cla udia ne Ferreira Dia s - MD. Po st-G raduatio n Co urse Student (MSc), in Head and N eck Surg ery o f Helió po lis Ho spital (HO SPHEL), São Paulo , Braz il.
Joã o Pa ulo Aché de Freita s - MD. Head o f Patho lo g y Department, ABC Medical Scho o l, Santo André, Braz il. Rica rdo Pires de Souza - MD. Sub Co o rdinato r o f the Po st-G raduatio n Co urse in Head and N eck Surg ery o f Helió po lis Ho spital (HO SPHEL), São Paulo , Braz il.
Sources of Funding: N o t de c la re d Conflict of interest: N o t de c la re d La st received: 2 1 aug ust 1 9 9 8 Accepted: 1 5 o cto ber 1 9 9 8 Address for correspondence: Abrão Rapo po rt
Rua Co nêg o Xavier 2 7 6 - 1 0 ° andar CEP 0 4 2 3 1 -0 3 0 - São Paulo / SP - Brasil E-mail: cpg cp.ho spel@ ibm.net
