Year : 1968 | Volume
: 16 | Issue : 2 | Page : 53--62
Malignant melanoma of the iris
Plainsfield, New Jersy N.Y, USA
Plainsfield, New Jersy N.Y
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Samuels L. Malignant melanoma of the iris.Indian J Ophthalmol 1968;16:53-62
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Samuels L. Malignant melanoma of the iris. Indian J Ophthalmol [serial online] 1968 [cited 2020 Jul 5 ];16:53-62
Available from: http://www.ijo.in/text.asp?1968/16/2/53/37493
Malignant melanomas are the most common malignant intraocular tumors. They may occur anywhere in the uveal tract but are most common in the choroid and rare in children and in negroes. 6 per cent of melanomas of the uveal tract are malignant melanomas of the iris. They are rarely bilateral.
The etiology is unknown. They can arise from pre-existing benign melanomas or nevi of the iris stroma. They are most often congenital and have been observed for many years. At one time all malignant pigmented tumors of the uveal tract were believed to arise from the mesenchymal melanocytes and were called melanosarcomas. Recent work has provided circumstantial evidence that the melanocytes of the uveal tract are of neural crest derivation from the sheaths of Schwann, altho they may be of complex derivation, partly melanocytic, and partly Schwannian.
Pigmented lesions may arise from any of the zones of the iris and have different clinical appearances and malignant potentialities. The benign melanomas of the iris are often called Nevi. These are probably developmental malformations and probably originate from melanocytes and are placed anteriorly and somewhat raised above its surface. They are rather frequent in eyes bearing a malignant melanoma of the choroid. They may be thin, flat, brown to black, circumscribed aggregations of stromal melanocytes on the anterior iris surface, small (2.5 mm), which rarely increase in size and number. These latter may be called freckles (provided no equivalence is implied with freckles in the skin which are due to pigmentation of the basal cell layer). The nevi and benign melanomas are larger, circumscribed, slightly elevated dome-shaped lesions, either lightly or heavily pigmented, and may increase in size and pigmentation at certain periods of life. Nevi can become malignant as shown by a change in size, papillary distortion, increase in pigmentation, new vessel formation, and alteration in the iris structure.
Malignant melanomas of the iris may arise from any zone, superficial or deep. They may appear as isolated neoplasms, elevated, increase progressively in size, and show new vessel formation; or they can appear as flat diffuse lesions involving sectors or the entire structure of the iris without forming a distinct mass, and the heterochromia becomes an important diagnostic sign. They tend to form a dense laver of tumor cells which spread peripherally to the anterior chamber angle and infiltrate into the pigment epithelium and posterior chamber. They may produce a glaucoma when they infiltrate into the corneal-scleral trabecular spaces. They may extend along the intrascleral plexus of vessels to the external eye. Hyphema may be an early sign and inflammation may be produced early by melanomas, obscuring the presence of the tumor for some time.
The distinction between benign and malignant melanomas of the iris is often difficult but certain features favor malignancy such as the darkening or growth of a pre-existing pigmented lesion with extensive invasion of iris stroma, heterochromia, ipso lateral glaucoma, distortion of the pupil, and spontaneous anterior chamber hemorrhage. Necrosis or inflammation of the iris stroma gives a picture of subacute or chronic iridocyclitis and is often treated as such.
The tumor is usually elevated with a rough or smooth surface and fairly sharply defined margins. Many new vessels can be seen in lightly pigmented lesions and this is quite suggestive of malignant melanoma. The pupil eventually fails to react to light and extension along the surface may lead to contraction, pupillary distortion and ectropion.
Gonioscopy is important where pigmented extension has occurred in the angle, trabecular meshwork, and the ciliary body.
Malignant melanomas of the iris exhibit all the cell characteristics of malignant melanoma of the ciliary body and choroid but have more of a tendency towards relatively benign spindle cell tumors. They rarely metastasize and the mortality is much less than similar tumors of the ciliary body and choroid. They are easily seen and are removed earlier, and are observed at an earlier age than those of the ciliary body and choroid. There may be local infiltration to the outside. Regardless of histological appearances, prognosis is gooci,if the tumor is completely removed -either by iridectomy or enucleation.
Differential diagnosis is mainly from benign melanomas; sarcoids, which are non-pigmented and have sarcoid lesions elsewhere; juvenile xanthogramiloma which occurs in early childhood, and is ushered in by a spontaneous hyphema and has cutaneous xanthomatous lesions; congenital melanosis; and cysts which are frequently bilteral and transilluminate well.
Consists of excisional or diagnostic biopsy, especially if papillary or mild zonal, and enucleation in the case of diffuse melanomas or where there is extension to the angle and ciliary body.
I present here 4 cases I have come across which illustrate some of the points I have made in the intorduction.
Woman of 54 years complained of pain and blurring of vision (20/50) of 3 weeks duration in the right eye. The tension was 50 mm. Schiotz. A pigmented mass was seen at the angle on the temporal side extending from the iris. Gonioscopy revealed a pseudo angle with increase of pigmentation of the peripheral surface of the iris involving a considerable area of the angle.
[Figure 1] shows the appearance of the angle on section examination of the tumor after enucleation. On the temporal side corneal-scleral trabeculae, the root of the iris and the peripheral portion of the anterior surface of the iris were infiltrated by spindle-type cells. The pigment was mildly pigmented and pigment was also seen in the corneal-scleral trabeculae of the opposite angle. Schlemn's canal was obscured by tumor cells and some cells were in the confines of the canal itself. There was no apparent extension beyond the canal.
A man, 77 years old was first treated by an ophthalmologist, with drops for his right eye which had become red and painful. When seen two months later the eye was stony hard but not painful. It transilluminated well in all directions. He came back a month later with the eye which had turned blind and very painful. He refused enucleation at that time but came back four months later, pleading for enucleation as the pain in the eye was unbearable. He died 6 months after the enucleation.
On section examination of the enucleaed eve [Figure 2] the nasal iris was found thickened and filled with cells of malignant melanoma of the mixed type with an outgrowth completely covering the surface and extending into the angle. The corneal-scleral trabeculae were invaded and Schlemn's canal was filled with spindle cells which extended into the aqueous veins leading from the canal. There was extension of the spindlecells into the emisseria of the anterior ciliary vessels.
Similarly, the ciliarv body [[Figure 3] on the nasal side was almost completely infiltrated by tumor cells and broken-down pigment, which extendcc] along the zomules.
The most interesting part of this case was that there was an implantation growth on the surface of the papilla, which was deeply cupped, with extension on the inner surface of the adjacent retina. [Figure 4] None of the sections studied showed any demonstrable tumour of the choroid.
We can conjecture that some tumour cells broke away and dropped into the postlental space and through Cloquet's canal to the papilla where they took root and spread. No similar implanation growth has been previously reported to our knowledge, although Reese has seen 1 instance of an implantation growth on the iris from a malignant melanoma of the choroid.
A man 41 years old had a spontaneous hyphema. When this cleared a large dark mass was seen in the lower outer quadrant of the chamber [Figure 5]. He had not reported himself for any ocular trouble previously as his vision was normal. [Figure 6] shows the tumour in a cross section, which is a malignant melanoma.
A girl 12 yews old was brought by her mother who had noticed a small salmon-pinkish mass at periphery of the anterior chamber of the right eye at 10 o'clock position [Figure 7].
This grew in one month to the papillary border and extended from 11 to 9 o'clock. There was no pain, vision tension were normal. There were no skin manifestations of xanthomas or sarcoids.
This case was first reported by me in 1963 as Juvenile Melanoma of Iris and Ciliary Body. The tumor was of pinkish hue and had some blood vessels on its knobby anterior surface. There was no appreciable pigmentation. The tumor completely filled the angle and was in apposition to the posterior surface of the cornea, visual acuity was 20/20 and the pupil reacted well to light and accommodation.
The tumor was excised by radial incisions and tearing away at the root. [Figure 8]. Subsequent microscopic examination of the torn iris edges showed the tumor extending to the margin. Histologic study showed a well vascularised tumor composed of rather uniform nevus cells with moderate spindling and some areas containing epithelioid cells with large nuclei, coarse chromatin, and occassional mitoses [Figure 9].
The tumor was called a Juvenile melanoma because of the age of the patient, 12 years, who was a year away from the onset of her menses. We were influenced by the work of SPITZ AND ALLEN on cutaneous melanomas in pre-pubescent children, in whom, altho the histological findings correspond closely to those found in true malignant melanomas, the clinical behavior is that of a benign tumor. Since these tumors of the iris rarely metastasize and have a low malignant potential, conservative rather than radical surgery seemed justified.
She was watched closely and one year later a small nubble of whitish tissue was seen at the ciliary margin of the iris colobma. [Figure 10] This was soon after an operation on her spine, during which hospital stay she had her first menses. This mass seemed to be confined only to the anterior portion of the ciliary body and apparently did not involve the pars plana. After much deliberation and consultation, it was again decided to be conservative for several. reasons:- her vision was still 20/20 corrected; she had good binocularity; a full year had passed and if there were to be metastases, they might have already been seeded, altho these tumors rarely metastasize. Several authorities felt there was a 50/50 chance of saving the eye and its vision, altho an enucleation was undoubtedly the safest course. We were swayed, perhaps unduly, by the decision of the parents, who wanted her to have that 50/50 chance to keep her eye, after we had carefully explained the possible risks if enucleation were not done.
A cyclectomy was performed in May 1963 by Dr. Gerald Kara of the New York Eye & Ear Infirmary. This operation was without any complication and a barrage of diathermy completely encircled the tumor a few millimeters from the margins and extended posteriorly to the ora serrata. The post-operative course was surprisingly mild. [Figure 11] The histological findings were the same as formerly and the tumor cells extended to the edges of the excised mass. We hoped that the diathermy barrage may have killed any stray localised extension beyond the line of excision.
A follow up report was published in the Transactions of Nov-Dec. 1965 giving the status of the patient 2 years after the cyclectomy, 3 years after the initial operation. At that time the general health of this adolescent young lady was excellent and the visual acuity in the right eye was 20/30 corrected, with good binocularity. The diminished vision was felt to be due to a fine pigment deposition on the anterior surface of the lens capsule, which had not become appreciably more noticeable in the past 6 months.
She was kept under monthly observation and no evidence of recurrence was noted until December 1966 when two small excrescenses were seen in the periphery of the iris at 7 and 6 o'clock and a small nodule was present at 12 o'clock. The visual acuity was still 20/30 corrected, and the tension was normal. Gonioscopic examination was not conclusive. A recurrence was diagnosed and enucleation done.
The histologic section confirmed the presence of a recurrent tumor. [Figure 12],[Figure 13] The new growth of predominantly epithelioid cells was along the side of the cyclectomy wall, into the overlying subconjunctival area, and in the angle of the other side, just barely involving the anterior part of the ciliary body. [Figure 14] There was a small mass at the nasal equatorial region of the lens in the posterior chamber. There were some flattened cells on the anterior capsule which were probably malignant melanoma according to Prof. Adalbert Fuchs, who examined the specimen. There was also a small tumor of the tip of the iris [Figure 12] which had the same kind of regularly arranged epitheliod cells as the main tumor in the contralatral angle.
This slide was sent to four international authorities and I am most grateful for their comments. Professor A. FUCHS remrked "The specimen shows that this case is a very malignant case altho it took 3 years and a half to show new manifestations. The cells in Schlemm's Canal and also subconjunctival area are tumor cells. I do not think that an early enucleation would have changed much. The filling of the filtration angle and pectinate ligament by tumor demonstrates the cells would enter freely into the blood stream, the reason of the malignancy.
Professor Norman Ashton writes "We now know a good deal more about malignant melanomas of the iris than when I discussed this condition iii 1962. First, I would say today that there is no separate histological category of juvenile melanoma in the uvea, altho of course it remains a possibility that melanomata may behave differently in the young person, as they may too in pregnancy. Your case then shows a typical spindle celled malignant melanoma of the iris which has now recurred and invaded the opposite side, but we are now more sure than ever that in such a recurrence these tumors rarely metastasize. I would have thought that the prognosis in this case was quite good, and I still feel that it was worth trying to cure it with a cyclectomy".
Dr. Algernon B. Reese notes "I feel sure that the tumor may be viewed as a more malignant one in every case after it has recurred twice We know that the statistics indicate that iris and ciliary booby melanomas seldom metastasize, but these figures are based on primary tumors. Were similar figures available for recurrent tumors, I do not think they would be as good As you know, the term juvenile melanoma referrs to a tumor in pre-puberty ages which have a malignant cytology but a benign clinical course. The general feeling now is that these were only a special type of nevus and cannot be compared to the melanomas that we sec in the uvea. I feel, and I think that most of the men that I know feel, that uveal melanomas in children have the same prognosis as in adults. The exception seems to be those that affect the iris."
Dr. Lorenz E. Zimmerman comments"……I concluded that this was mainly an epitheliod type melanoma of the iris and ciliary body. I do not believe one can differentiate this from other malignant melanomas that might be encountered in adults. I think it is unfortunate that the term "Juvenile Melanoma" was even introduced because even in the case of cutaneous lesions, these tumors are not confined to the prepubertal age group and also because they are not melanomas in the sense of being malignant tumors. The more recently introduced term of spindle epithelioid nevus is preferred for those lesions of the skin.
"It is even more unfortunate that this term (Juvenile Melanoma) has been introduced into ophthalmic pathology because there is even less justification for it here. Malignant melanomas of the uveal tract occurring in the prepubertal child may give rise to metastatic disease and a fatal outcome just as is true of malignant melanomas in the adult. There is no way one can differentiate, histologically or by behavior, the malignant melanoma of the uveal tract encountered in the child and that of the adult.
"It is always exceedingly difficult to prognosticate the behavior of individual melanomas of the uveal tract, regardless of the age group and I would certainly be reluctant to say that the prognosis in the present case is favourable. There certainly is evidence of extraocular extension and this, together with the large proportion of epithelioid cells, makes me feel that the prognosis should be guarded".
Professor Ashton mentions a case in his files "of a 10 year girl who had an exactly similar lesion treated by iridocyclectomy. The lesion recurred a year later and the eye is enucleated-it showed invasion of the operation scar and of the ciliary muscle. The child is alive and well today ten years afterwards", Dr. Kenneth C. Nieberg, Pathologist at Muhlenberg Hospital, Planfeld, N.J. feels that the uniformity and lack of anaplasia of the tumor cells, the slow progression of the tumor, and the lack of extensive progressive growth suggest a low grade malignancy.
My own feeling is that after having watched and lived with this case for 4½ years, the next case of malignant melanoma in a young person which comes under my care will probably receive an early enucleation if it extends to the angle. I would still be inclined to do a complete radial iridectomy if only the pupillary and mid-ciliary portions were involved.
Case histories of 4 cases of malignant melanomas of the iris, the angle and the ciliary body are described. Case No. 4 in a girl, 12 years old, is described in great detail with a complete follow tip of 4½ years.
Opinions of 4 international authorities on the sections of the enucleated eye in case 4 are stated together with their comments on the malignancy in juvenile (prepuberty) forms of the condition, which is ordinarily regarded to below.