Journal of Neuro-Ophthalmology, September 1986, Volume 6, Issue 3

Adult intrasellar teratoid tumor.

Intracranial teratomas rarely occur in adults. The most common sites are the pineal followed by the suprasellar or hypothalamic areas. Infrequently, teratomas can arise within the sella turcica and mimic a pituitary adenoma or craniopharyngioma. Teratoid tumors contain tissue arising from only two of the three primitive germ layers, whereas teratomas have elements of all three. The following case illustrates the unusual occurrence of an intrasellar teratoid tumor in a 33-year-old man.

( 1YHh Raven Pre":>~, Nevv York Adult Intrasellar Teratoid Tumor Michael P. Merchut, M.D., Juse Biller, M.D., Mona Ghobrial, M.D., and Michael Fine, M.D. In tr.1(r.1 111.1 I lL'r.ltl)m.ls r.1re"· lllcur in .1dulh. The must Cl)mml)J1 "Itl'" .1n' till' pilll'.ll Il)lIll\ved bv the "upra"ellar l)r h\Tl)th.ll.1mic.Hl,.b. Inln'Ljul'ntlv, Il'r.ltum.l" c.1I1 ari"e within the "dl.l turcic.l .md mimic a pituit.1rv adenuma l)r Lrani,)pharvn~il)m.l. Ter.ltl)id tumur" curitain tissue .1ri"in~ Iwm l)n'" twu l)1 the threl' primitive germ I.lyer", wherea" ter.1tl)m.l" h.1\"e eIL'ment" 01 all three. The lul­k) wing (a"e dlu"tr.ltl'" the unu"u.l1 lKCUrrl'n(e l)1 an in­trasellar teratl)id tumnr in a 33-vear-nld man. Key Words: Intra"dlar le"il)';- Teratnma-Adult­Ge~ m (ell tunwr. From the Departments of Neurology (M.P.M.), Neurop.1­thology (M.G.), and Radiology (M.F.), Lovol.1 Universitv Ml,d­iea/ Center. Maywood, Jllinois; .1I1d the Dep.nll1ll'nt of Nl'u­rology, University of Iowa Hospit.1ls .md Clinics (I.Il.), IOW.1 City, Iowa. Address correspondence and reprint reljul'sts 10 Dr. M.I'. Merchut, Department of Neurologv, Lovol.1 Univl'rsit\' 1\1l'dil',11 Center. 2160 South First Avenue, May~ood, II. h0153, US.A. /75 Teratomas are unusual tumors, showing as great a diversity in their location as in their his­tology. Various theories have been proposed to ac­count for their pathogenesis. A germ cell origin could explain how teratomas arose in distant and usually midline sites, reflecting the central yolk sac origin of germ cells, and their subsequent ameboid migration to the developing gonads. The intragonadal prevalence of teratomas lends further support to this theory, although the initiating cel­lular factors remain unknown (1). On the other hand, pluripotential, nongerminal embryonic cells could be sequestered at a critical time from "in­ducing" or "organizing" tissues to develop later into a morphologically diverse teratoma. Experi­mental data substantiate this possibility (2,3). Damjanov and Solter (2) feel both these theories have merit, in that either germ or nongerminal embryonic cells could develop into teratomas if local unknown "organizing" factors failed at crit­ical times. Even extraembryonic tissue can give rise to teratomas, as shown by the experiments of Sobis and Vandeputte (4) on displaced visceral yolk sac. Fusion of haploid germ cells is another possible mechanism of teratogenesis according to Ashley (S). Nicholson (6) has argued against the theory of teratomas representing an "aborted" or "blighted twin." Most teratomas, although mor­phologically quite complex, tend to lack the verte­bral axis a fetus would have, with rare exceptions (6). In summary, no single theory of teratogenesis explains all of their behavior. Intracranial germ cell tumors, as most of their systemic counterparts, tend to arise in or near the midline, based on the various embryonic theories 01' origin already discussed. The germinoma, iden­tical to the testicular seminoma or ovarian dysger­minoma, is a more common type (7). The rarer teratoma accounts for only a.s'x, of all intracranial tumors (excluding the fatal, often massive congen­ital teratoma of infants) (8). Strictly speaking, tera- 17{) M. P. MLRCHUT ET AL. tomas must contain tissue difiL'rl'ntiatl'd from l',lCh of the three germ I,wers. Areas of slju,mHlllS epi­thelium, glandulM structures, hair, bone, cMtilage, mesl'nchvn1l', ,1nd l'Vl'n neuroectodermal ell'­nll'nts mav be Sl'l'n. Tumors ClJllt,lining compo­nents of only two germ byl'rs might be described rather as "teratoma-like" or "tl'ratoid," although the 1,1 tter term has been used by some to signi fy it'ss differl'ntiakd, more "m'llignant" appearing tissue (9). Tunlllrs with 1l',1tures of both ger­minoma and teratoma have been classified at times as "mixed germ cell" tumors. Older nomen­clature has been even more confusing. Cer­minomas arising in the pineal and called "pinea­lomas" were relabeled "atypical teratomas" by Russell and Rubinstein (10). Cerminomas arising in the hypothalamus, away from their more usual pineal location, were called "ectopic pinealomas." Terms such as germinoma, teratoma, and teratoid tumor are perhaps best to use at present. The pineal region is the most common site for these germ cell tumors, followed by a suprasellar or hypothalamic location. Although the origin of an extensively infiltrating tumor is often obscured, rare cases apparently arising from the posterior fossa or sella have been described (1,9). Teratomas and germinomas usually occur before the fourth decade of life (1,9,11,12). This report summarizes our experience with a 33-year-old patient who had an intrasellar teratoid tumor. CASE REPORT A 33-year-old man developed left frontal head­aches 2 months before admission. During this pe­riod he was easily tired, frequently felt chilled, and lost IS'';'' of his body weight from decreased appetite. The last time he needed to shave was 1 month before admission and he noted decreased libido for 2 months. There was no goiter, gyneco­mastia, or prior medical illness. Diminished vision of the entire left eye, attributed to a corneal abra­sion, worsened to blindness over the previous month. Right temporal vision likewise deterio­rated over 2-3 weeks. Examination upon hospitalization revealed an alert, pale, slender white man. Facial hair was sparse, but pubic and axillary hair were present. Mild testicular atrophy was noted. There was no light perception in the right temporal and entire left visual fields. Acuity was 20/30 in the right eye. There was optic nerve pallor and a relative afferent I Clil1 NClIro-"l'hlhlllll/o!, Vol. 6. No . .1. 198b FIG. 1. Contrast-enhanced coronal CT (four serial 3-mm sections) of sellar mass demonstrating erosion of sellar floor (white arrows) and su­prasellar extension (black arrows). Note the inhomogeneous enhance­ment and irregUlar outline of the tumor. ADULT INTRASLLLAR TERATOID TUMOR /77 pupillary defect in the left eye. Tlw remaindo.:'r of the neurological and general physical examination was normal. Laboratory ev.lluation dt:'lllonstrated hypopitui­tarism: T4 = 2A f.lg/dl (normal, 5.0-12.0). TJ = 60 ng/dl (normal, 80-1(0), thyroid-stimulating hormone (TSH) < 1.0 f.lU/ml (normal, 1.0-4.0). follicle-stimulating hormont:' (FSH) <2 MIU/ml (normal, 0-15), LH <2 MIU/ml (normal, 2-15), testosterone <10 (I1lHmal, 250-1,200 ng/dl), adrel1L1Corticotropic Illlrnlllllt:' (ACTH) <20 pg/ml (normal, 0-80), AM cortisol = 2 f.lg/dl (normal, 6-25), and prolactin = 49 ng/ml (normal, 0-12). Serum alpha-fett)protein was 8.7 ng/ml (normal, 0-11) and no bet.l-human ch~)rionic gonadotropin (HCG) was detected. Computed tomography (CT) showed a 3-cm ir­regular, inhomogeneous, contrast-enhancing sellar mass eroding the floor of the sella and ex­tending into the suprasellar cisterns (Fig. 1). The third ventricle was not involved. Cerebral angiog­raphy revealed elevation of the proximal A-I seg­ments of both anterior cerebral arteries, which was greater on the left (Fig. 2). Prominent cav­ernous arterial branches appeared to be supplying the sellar area, while a faint, irregular, suprasellar blush was noted in the early venous phase. The patient underwent a subtotal trans-sphen­oidal resection of the sellar tumor, which was felt clinically to be a nonfunctional chromophobe ade­noma. The sellar floor was soft and eroded but in­tact. Upon opening the sellar floor, a large, fleshy­gray fibrous mass was exposed. A total excision was prevented by the extensiveness of the tumor and brisk bleeding. Histological examination revealed multiple cystic structures with various linings. Some were single layers of low cuboidal or columnar cells, while others had pseudostratified or stratified layers, reminiscent of alimentary and respiratory epithelium (Fig. 3). Between these structures were cellular areas of mesenchymal origin (e.g., carti­lage, figure 4) or less differentiated cells. No ecto­dermal elements were seen, and no glia were de­tected by glial fibrillary acidic protein (GFAP) stains. Since only endodermal and mesodermal tissues were present, the tumor was "teratoid" rather than a teratoma. Mild diabetes insipidus was treated postopera­tively in addition to hormonal replacement therapy. Three weeks later there was subjective impairment in the right nasal field, so a left frontal craniotomy was performed and the residual tera­toma was removed. At 2-year follow-up, his visual deficit remains stable. FIG. 2. Elevation (arrow) of proximal A-1 segment of left anterior cerebral artery. (Subtraction view of se· lective left carotid angiogram). Enlarged cavernous branches of the internal carotid artery are present (double arrow). DISCUSSION Suprasellar germ cell tumors often present with the triad of diabetes insipidus, visual deficit, and hypopituitarism (12-15). Of these, diabetes insip­idus is usually the presenting symptom, often long before the whole triad is evident, indicating hypothalamic involvement. Takeuchi et al. (15) re­ported this in nine of 18 cases, \·."hile Kageyama and Belsky (16) found this trend in 11 of 16 supra­sellar/ chiasmal germinomas. Our patient, we believe, presented with an in­trasellar lesion. It appears that this teratoid tumor arose primarily in the sella, causing panhypopitui­tarism and severe sellar erosion. Suprasellar germ cell tumors usually create only mild sellar defor­mities (14,15). Subsequent chiasmal extension led to visual loss in our patient, but no initial clinical hypothalamic involvement, typical of a suprasellar teratoma, was present. Diabetes insipidus oc­curred only postoperatively, and was not a prior symptom. Such findings and history in an adult I Cli" Nc"ro-opil/llIli",oi, Vol. 6, No.3, 1986 17X M. P. MERCHUT ET AL. FIG. 3. Microscopic section of tumor showing glandular structures lined by tall co­lumnar epithelium (arrows). surrounded by loose connective tissue (Hematoxylin and eosin, A 180.) FiG. 4. Microscopl'c sectl'on OT tumor with an island of cartilage (arrow) and a gland lined by a low cuboidal layer (double arrow) separated by connective tissue. (Hema­toxylin and eosin, x 180.) ADULT /NT/\ASELLA/\ TE/\ATOJD TUMOR TABLE 1. Intrasellar germ cell tumors· 179 Age (yrs), Cranial nerve Tumor Reference sex dysfunction Endocrinopathy histology Troland and Brown (17) 14, M II Precocious Germinoma puberty (ectopic pinealoma) Simson et al. (18) 11,M III, IV, VI None Germinoma Ghatak et al. (19) 19, M II, VI Panhypopituitarism Germinoma Ghatak et al. (19) 13, F None Panhypopituitarism Germinoma Dno et al. (20) 12, F II, III, VI Panhypopituitarism, Embryonal elevated beta-HCG, carcinoma and alpha-fetoprotein Page et al. (21) 19, M III, VI Subclinical Mixed germ Hypothyroidism, cell elevated beta-HCG Fults and Kelly (22) 15, F None Secondary amenorrhea, Mixed germ elevated beta-HCG, cell and alpha-fetoprotein Present report 33. M II Panhypopituitarism Teratoid tumor • Modified from Page et al. (21) patient would be more clinically suggestive of pi­tuitary adenoma, with chiasmal extension, or of craniopharyngioma. The previous cases of germ cell tumor mimicking an intrasellar mass were re­viewed (17-22). These seven patients had pitui­tary involvement without diabetes insipidus, and thus were similar to our patient (Table 1). Cases reported before the advent of CT scan­ning may have been extensive suprasellar tumors secondarily involving the sella. Four "pituitary" teratomas were collected from the older literature by Sweet (23), but clinical and anatomical details were lacking. At times other sellar tumors may show morpho­logical similarities to those of teratomatous nature, such as craniopharyngiomas, epidermoid cysts, and Rathke cleft cysts. Epidermoid cysts are lined entirely by squamous epithelium, whereas der­moid cysts contain sweat or sebaceous glands and hair follicles. Intracranial dermoids occur less often than epidermoid cysts, which occasionally occur in the parasellar region. Both tumors prob­ably originate from epithelial tissue that is seques­tered within the central nervous system upon clo­sure of the fetal neural groove (9,10). Craniopha­ryngiomas are commoner, accounting for 3(J(, of all intracranial tumors according to Rubinstein (9) and Russell (10). They appear epithelioid, with multiple small cysts lined with columnar or squamous cells. Craniopharyngiomas may de­velop from squamous cell aggregates which are found where the pars distalis of the adenohypo­physis borders on the infundibular stalk. Rather than representing embryonic remnants of Rathke's pouch, these squamous cells may be a metaplastic transformation of adenohypophyseal cells (24,25). Rathke cleft cysts are considered to have truly originated from Rathke pouch rem­nants. Intrasellar but occasionally suprasellar in location, they basically are cysts lined by cuboidal cells that at times are ciliated (26). The histology of these other sellar tumors, however, differs from the teratoid tumor in our patient. Since teratomatous tumors rarely arise within the sella, they must be distinguished from pitui­tary adenomas, meningiomas, optic gliomas, cra­niopharyngiomas, epidermoid cysts, and Rathke cleft cysts. Complete surgical excision is the rec­ommended therapy for sellar teratomas. Postoper­ative radiation therapy may be of benefit if "malig­nant" histological features were present, or if the tumor was primarily that of the more radiosensi­tive germinoma type (13,15). 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