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Idiopathic Cyst of the Iris Stroma
IDIOPATHIC CYST O F T H E IRIS STROMA JOAN MULLANEY, M.D.,
AND CATHERINE FITZPATRICK,
M.B.
Dublin, Ireland
measuring 20 X 20 X 21 mm with an at tached 10-mm length of optic nerve. An in definite oval crenated area in the inferonasal portion of the anterior chamber was visible through the cornea. The horizontally opened specimen showed that a large smooth-walled cyst containing a little cloudy fluid filled the anterior chamber but did not extend across the pupil (Fig. 1). The iris pigment layer interposed between the cyst and the lens. No other intraocular abnormality was found. After fixation in 4% glutaraldehyde and embedding in par affin, 8 ητμ. sections were cut and hematoxylin and eosin, PAS, and alcian blue stains were done. A total of 589 serial sections of the pathological area were examined; of these, 323 slides contained the cystic foci. The inner half of the sceral layer had failed to form fully in the inferonasal corona ciliaris region. Instead, a small coloboma lined by modified squamous epithelium with some goblet cells communicated for a dis tance of 64 ηιμ with another cavity also colo bomatous in origin in the ciliary muscles (Fig. 2 ) . At deeper scierai levels, closure of the co loboma had taken place and the epithelial di-
Incomplete coloboma of the anterior ter minal portion of the sciera also involving the ciliary muscles without a colobomatous de fect in the ciliary body and iris must be ex tremely rare. A search of the literature failed to reveal such a case. Idiopathic unpigmented iris stromal cysts are also of in frequent occurrence. In 1967, Naumann and Gfeen,1 describing the pathology of two eyes containing non-pigmented iris cyst from the files of the Armed Forces Registry of Oph thalmic Pathology in Washington, D.C., re viewed previous reports on this subject and found "only one paper describing such a cyst within an intact globe" (that of Böhm2 re ported in 1916). It was not possible for them to demonstrate the mode of origin of their cysts. An enucleated eye with an iris stromal cyst, associated colobomata of the sciera and ciliary muscles provided an unusual opportu nity to study histologically the evolution of one of these cysts. CASE REPORT
A six-month-olcl girl was brought to the hospital because of a sore eye of one month's duration, dur ing which time there was a history of irritability and rubbing of the eye. There was no history of pre-, postnatal trauma or other episode. On ex amination, the. left eye was normal, but in the right eye, the lens was seen to be disclocated and there was a swelling in the iris from 7 to 9 o'clock. No red reflex could be elicited. General examination showed the child was healthy. Urine was screened chromatographically and revealed only a trace of van lmandelic acid. Enucleation was performed on suspicion of tumor. PATHOLOGY
The specimen consisted of a right eye From the National Ophthalmic Pathology Labo ratory of Ireland, Royal Victoria Eye and Ear Hospital, and the Children's Hospital, Dublin. ■Reprint requests to Joan Mullaney, M.D., Na tional Ophthalmic Pathology Laboratory of Ire land, Royal Victoria Eye and Ear Hospital, Dublin 2, Ireland.
Fig. 1 (Mullaney and Fitzpatrick). Globe opened to show cyst in anterior chamber at pupillary mar gin. 64
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65
Fig. 2 (Mullaney and Fitzpatrick). "Conjunctival" epithelium with squamous and goblet cells lining coloboma. Prominent scierai blood vessels (hematoxylin and eosin, x50).
verticulum here presented as an intrascleral microcyst (Fig. 3-A). The longitudinal cili ary muscle was incomplete for 256 ιημ ( Fig. 3-B) and the epithelium, covered by a fine layer of compressed mesoderm, ramified in the circular fibers of the ciliary muscle, cre ating epithelialized septae (Figs. 3. A and B). The uveal pigment layer was intact at all levels. The cyst ultimately filled the anterior chamber. Anteriorly, it touched the corneal endothelium and the anterior lens capsule posteriorly from which it was separated by the synechial pigment layer. In some planes of sectioning the iris stroma was pushed lat erally (Fig. 4). The mesodermal capsule was barely identifiable where the cyst reached its greatest diameter and tension had also caused flattening of the epithelium. The up permost and terminal edge of the cyst formed an integral part of the central por tion of the iris stroma. The sphincter pupillae muscle had devel oped normally throughout and the pigment layer extended independently and centrally
behind the cyst (Fig. 5). Desquamation of epithelial cells mixed with goblet cell prod ucts gave rise to scattered free intraluminal debris. Nothing histologically remarkable otherwise was found. DISCUSSION
The origin of unpigmented iris stromal cysts is controversial. NadaP (1911) and Koch" (1921) believed that cells from the developing lens were dis placed into the iris stroma. Politzer5 (1953) and Mann" (1957) suggested a derivation from the cells of the neural ectoderm at the rim of the optic cup while still unpigmented and before the development of the iris. Their concept would appear to be confirmed by the findings in the present case. Sequestration of an island of ectoderm in the primitive meso derm along the fetal fissure could account for the scierai and ciliary muscle colobomata. The prominence of the blood vessels both episclerally and intrasclerally in the sections at the level of this deep epithelium (Fig. 2)
66
AMERICAN JOURNAL OF OPHTHALMOLOGY
JULY, 1973
Fig. 3 (MuUaney and Fitzpatrick). (A) Portion of cyst enclosed in sciera. Ciliary processes irregular hematoxylin and eosin, χ12.5). (Β) Cyst with loculation. Scierai pouch at site of coloboma (hematoxylin ind eosin, X12.5).
Fig. 4 (MuUaney and Fitzpatrick). Cyst causing distortion of iris (hematoxylin and eosin, X12.5).
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Fig. 5 (Mullaney and Fitzpatrick). Cyst in iris stroma at pupillary level (hematoxylin and eosin, X12.5) might suggest that its dislocation could have occurred in association with vascularization of the embryonic cleft. Epithelialization of available cleavage lines may then have taken place along the uveal segment relating to the coloboma, the remainder of the anterior chamber forming normally. The pigment epithelium, the sphincter pupillae, and the lens developed in the conven tional manner and merely showed secondary anatomical distortion. Naumann and Green 1 felt that since these cases should be amenable to iridectomy, un necessary enucleation may be done. It is of interest to find that in one of their patients (Case 1) the cyst which appeared to arise from the ciliary body recurred within four days of excision and recurred again. The eye had then to be enucleated because of surgical complications. In our case, the congenital de fects we found showed the difficulty of at tempting to extirpate its lesion. The major portion of the cyst lay in the anterior cham ber but there were intrascleral and intraciliary muscular foci containing cells capable of continued epithelialization and perhaps se cretion through metaplasia to goblet cells. These microscopic foci would be difficult to
remove and could be expected to remain as potential areas of cyst formation. If the malformations demonstrated by this present study pertain to cases of "spontane ous stromal" cyst of the iris, then incomplete removal of the ectopic tissue must lead inevi tably to enucleation. However, local excision, if possible, with awareness of the likelihood of recurrence may still be a worthwhile pro cedure. SUMMARY
Enucleation was performed in a sixmonth-old child for suspected intraocular neoplasm. A large stromal iris cyst was found. Its lining epithelium was of conjunctival type. Sequestration of a focus of sur face ectoderm along the embryonic cleft ap peared to be associated with the formation of colobomata in the sciera and ciliary muscles. It is thought that segmental epithelialization of the mesoderm in the cleavage line from the coloboma during the formation of the an terior chamber facilitated the evolution of the large cyst. ACKNOWLEDGMENT
We thank Mr. R. Lester, F.I.M.L.T., for techni-
68
AMERICAN JOURNAL OF OPHTHALMOLOGY
cal aid, Mrs. D. Fanning for typing assistance, and Mr. J. Mulvanny for photographic help. REFERENCES
1. Naumann, G., and Green, W. R. : Spontaneous non-pigmented iris cysts. Arch. Ophth. 78:496, 1967. 2. Böhm, K. : Ein Fall von Spontaner Iriscyste mit Pathologisch-anatomischen Befund. Klin. Mbl. Augenheilk. 56:70, 1916.
JULY, 1973
3. Nadal, R.: Note sur la pathogenie des kystes séreux congénitaux de l'iris. Arch. Ophth. 31:363, 1911. 4. Koch, K. : Kongenitale Iriscyste. Klin. Mbl. Augenheilk. 67:407, 1921. 5. Politzer, G. : Die Enstehung der Spontanen epithelialen Iriscysten. von Graefe's Arch. Ophth. 153:497, 1953. 6. Mann, I. : Development Abnormalities of the Eye, 2nd ed. London, British Medical Association, 1957, p. 295.
OPHTHALMIC MINIATURE
The word manuscript, which within my memory used to be limited to a handwritten document, has been so misused recently by editors and printers (who ought to be the chief guardians of the purity of the English language) that it has come to mean anything short of full-blown print and is in fact usually typescript. What then is one to call the hand written version that comes before the typewriter ? I have seen holograph used, but that merely means written by oneself, and could equally well be applied to something one had written oneself on a typewriter: in any case (though it is accepted legal jargon) in scientific contexts it would invite confusion with the laser-derived pictures. There is a perfectly good word, chirograph, meaning something written by hand, which might be used for a "real" manuscript. B. Ell Reflections of a Lexicographer Lancet 1:479, 1973
AND CATHERINE FITZPATRICK,
M.B.
Dublin, Ireland
measuring 20 X 20 X 21 mm with an at tached 10-mm length of optic nerve. An in definite oval crenated area in the inferonasal portion of the anterior chamber was visible through the cornea. The horizontally opened specimen showed that a large smooth-walled cyst containing a little cloudy fluid filled the anterior chamber but did not extend across the pupil (Fig. 1). The iris pigment layer interposed between the cyst and the lens. No other intraocular abnormality was found. After fixation in 4% glutaraldehyde and embedding in par affin, 8 ητμ. sections were cut and hematoxylin and eosin, PAS, and alcian blue stains were done. A total of 589 serial sections of the pathological area were examined; of these, 323 slides contained the cystic foci. The inner half of the sceral layer had failed to form fully in the inferonasal corona ciliaris region. Instead, a small coloboma lined by modified squamous epithelium with some goblet cells communicated for a dis tance of 64 ηιμ with another cavity also colo bomatous in origin in the ciliary muscles (Fig. 2 ) . At deeper scierai levels, closure of the co loboma had taken place and the epithelial di-
Incomplete coloboma of the anterior ter minal portion of the sciera also involving the ciliary muscles without a colobomatous de fect in the ciliary body and iris must be ex tremely rare. A search of the literature failed to reveal such a case. Idiopathic unpigmented iris stromal cysts are also of in frequent occurrence. In 1967, Naumann and Gfeen,1 describing the pathology of two eyes containing non-pigmented iris cyst from the files of the Armed Forces Registry of Oph thalmic Pathology in Washington, D.C., re viewed previous reports on this subject and found "only one paper describing such a cyst within an intact globe" (that of Böhm2 re ported in 1916). It was not possible for them to demonstrate the mode of origin of their cysts. An enucleated eye with an iris stromal cyst, associated colobomata of the sciera and ciliary muscles provided an unusual opportu nity to study histologically the evolution of one of these cysts. CASE REPORT
A six-month-olcl girl was brought to the hospital because of a sore eye of one month's duration, dur ing which time there was a history of irritability and rubbing of the eye. There was no history of pre-, postnatal trauma or other episode. On ex amination, the. left eye was normal, but in the right eye, the lens was seen to be disclocated and there was a swelling in the iris from 7 to 9 o'clock. No red reflex could be elicited. General examination showed the child was healthy. Urine was screened chromatographically and revealed only a trace of van lmandelic acid. Enucleation was performed on suspicion of tumor. PATHOLOGY
The specimen consisted of a right eye From the National Ophthalmic Pathology Labo ratory of Ireland, Royal Victoria Eye and Ear Hospital, and the Children's Hospital, Dublin. ■Reprint requests to Joan Mullaney, M.D., Na tional Ophthalmic Pathology Laboratory of Ire land, Royal Victoria Eye and Ear Hospital, Dublin 2, Ireland.
Fig. 1 (Mullaney and Fitzpatrick). Globe opened to show cyst in anterior chamber at pupillary mar gin. 64
VOL. 76, NO. 1
IDIOPATHIC IRIS CYST
65
Fig. 2 (Mullaney and Fitzpatrick). "Conjunctival" epithelium with squamous and goblet cells lining coloboma. Prominent scierai blood vessels (hematoxylin and eosin, x50).
verticulum here presented as an intrascleral microcyst (Fig. 3-A). The longitudinal cili ary muscle was incomplete for 256 ιημ ( Fig. 3-B) and the epithelium, covered by a fine layer of compressed mesoderm, ramified in the circular fibers of the ciliary muscle, cre ating epithelialized septae (Figs. 3. A and B). The uveal pigment layer was intact at all levels. The cyst ultimately filled the anterior chamber. Anteriorly, it touched the corneal endothelium and the anterior lens capsule posteriorly from which it was separated by the synechial pigment layer. In some planes of sectioning the iris stroma was pushed lat erally (Fig. 4). The mesodermal capsule was barely identifiable where the cyst reached its greatest diameter and tension had also caused flattening of the epithelium. The up permost and terminal edge of the cyst formed an integral part of the central por tion of the iris stroma. The sphincter pupillae muscle had devel oped normally throughout and the pigment layer extended independently and centrally
behind the cyst (Fig. 5). Desquamation of epithelial cells mixed with goblet cell prod ucts gave rise to scattered free intraluminal debris. Nothing histologically remarkable otherwise was found. DISCUSSION
The origin of unpigmented iris stromal cysts is controversial. NadaP (1911) and Koch" (1921) believed that cells from the developing lens were dis placed into the iris stroma. Politzer5 (1953) and Mann" (1957) suggested a derivation from the cells of the neural ectoderm at the rim of the optic cup while still unpigmented and before the development of the iris. Their concept would appear to be confirmed by the findings in the present case. Sequestration of an island of ectoderm in the primitive meso derm along the fetal fissure could account for the scierai and ciliary muscle colobomata. The prominence of the blood vessels both episclerally and intrasclerally in the sections at the level of this deep epithelium (Fig. 2)
66
AMERICAN JOURNAL OF OPHTHALMOLOGY
JULY, 1973
Fig. 3 (MuUaney and Fitzpatrick). (A) Portion of cyst enclosed in sciera. Ciliary processes irregular hematoxylin and eosin, χ12.5). (Β) Cyst with loculation. Scierai pouch at site of coloboma (hematoxylin ind eosin, X12.5).
Fig. 4 (MuUaney and Fitzpatrick). Cyst causing distortion of iris (hematoxylin and eosin, X12.5).
VOL. 76, NO. 1
IDIOPATHIC IRIS CYST
67
Fig. 5 (Mullaney and Fitzpatrick). Cyst in iris stroma at pupillary level (hematoxylin and eosin, X12.5) might suggest that its dislocation could have occurred in association with vascularization of the embryonic cleft. Epithelialization of available cleavage lines may then have taken place along the uveal segment relating to the coloboma, the remainder of the anterior chamber forming normally. The pigment epithelium, the sphincter pupillae, and the lens developed in the conven tional manner and merely showed secondary anatomical distortion. Naumann and Green 1 felt that since these cases should be amenable to iridectomy, un necessary enucleation may be done. It is of interest to find that in one of their patients (Case 1) the cyst which appeared to arise from the ciliary body recurred within four days of excision and recurred again. The eye had then to be enucleated because of surgical complications. In our case, the congenital de fects we found showed the difficulty of at tempting to extirpate its lesion. The major portion of the cyst lay in the anterior cham ber but there were intrascleral and intraciliary muscular foci containing cells capable of continued epithelialization and perhaps se cretion through metaplasia to goblet cells. These microscopic foci would be difficult to
remove and could be expected to remain as potential areas of cyst formation. If the malformations demonstrated by this present study pertain to cases of "spontane ous stromal" cyst of the iris, then incomplete removal of the ectopic tissue must lead inevi tably to enucleation. However, local excision, if possible, with awareness of the likelihood of recurrence may still be a worthwhile pro cedure. SUMMARY
Enucleation was performed in a sixmonth-old child for suspected intraocular neoplasm. A large stromal iris cyst was found. Its lining epithelium was of conjunctival type. Sequestration of a focus of sur face ectoderm along the embryonic cleft ap peared to be associated with the formation of colobomata in the sciera and ciliary muscles. It is thought that segmental epithelialization of the mesoderm in the cleavage line from the coloboma during the formation of the an terior chamber facilitated the evolution of the large cyst. ACKNOWLEDGMENT
We thank Mr. R. Lester, F.I.M.L.T., for techni-
68
AMERICAN JOURNAL OF OPHTHALMOLOGY
cal aid, Mrs. D. Fanning for typing assistance, and Mr. J. Mulvanny for photographic help. REFERENCES
1. Naumann, G., and Green, W. R. : Spontaneous non-pigmented iris cysts. Arch. Ophth. 78:496, 1967. 2. Böhm, K. : Ein Fall von Spontaner Iriscyste mit Pathologisch-anatomischen Befund. Klin. Mbl. Augenheilk. 56:70, 1916.
JULY, 1973
3. Nadal, R.: Note sur la pathogenie des kystes séreux congénitaux de l'iris. Arch. Ophth. 31:363, 1911. 4. Koch, K. : Kongenitale Iriscyste. Klin. Mbl. Augenheilk. 67:407, 1921. 5. Politzer, G. : Die Enstehung der Spontanen epithelialen Iriscysten. von Graefe's Arch. Ophth. 153:497, 1953. 6. Mann, I. : Development Abnormalities of the Eye, 2nd ed. London, British Medical Association, 1957, p. 295.
OPHTHALMIC MINIATURE
The word manuscript, which within my memory used to be limited to a handwritten document, has been so misused recently by editors and printers (who ought to be the chief guardians of the purity of the English language) that it has come to mean anything short of full-blown print and is in fact usually typescript. What then is one to call the hand written version that comes before the typewriter ? I have seen holograph used, but that merely means written by oneself, and could equally well be applied to something one had written oneself on a typewriter: in any case (though it is accepted legal jargon) in scientific contexts it would invite confusion with the laser-derived pictures. There is a perfectly good word, chirograph, meaning something written by hand, which might be used for a "real" manuscript. B. Ell Reflections of a Lexicographer Lancet 1:479, 1973