Chinese Medicine, 2011, 2, 16-19
doi:10.4236/cm.2011.21003 Published Online March 2011 (
Copyright © 2011 SciRes . CM
Primary Pupillary Margin Cyst of the Iris Pigment
Rosanna Dammacco1, Giovanni Giancipoli1, Silvana Guerriero1,
Domenico P iscite l li2, Nicola Cardascia1
1Department of Ophthalmology and Otorhinolaryngology, Bari University, Bari, Ita ly
2Department of Pathological Anatomy, Bari Unive rsity, Bar i, Italy
January 13, 2011; revised February 2, 2011; accepted February 10, 2011
Purpose: Description of a patient with a solitary cyst of the pupillary margin iris pigment epithelium (IPE).
Methods: A 63-year-old man referred a suspected iris-ciliary body melanoma in his left eye. Based on both
clinical examination and ultrasound biomicroscopy, melanoma was considered unlikely. Surgery was under-
taken to correct recurrent deterioration of vision due to movement of the lesion across the visual axis. Results:
The lesion was excised completely. Ultrasound biomicroscopy and histopathological examination ruled out
melanoma and allowed a final diagnosis of primary pupillary margin cyst of the IPE, characterized of pig-
mented epithelium, with no connective tissue or vessels. No recurrences or fresh lesions appeared during a
one-year follow-up. Conclusions: Primary epithelial iris cysts are usually benign. Treatment is required only
in symptomatic patients and those with an uncertain diagnosis. Ultrasound biomicroscopy is indispensable to
confirm the clinical diagnosis, follow the clinical course and intervene if surgery is required.
Keywords: Melanoma, I ris Pigment E pithe lium, P up illary Cyst, S urgical Excision, Ultrasound Biomicroscopy
1. Introduction
Primary cysts in t he anterior segment, observed during a
routine eye examination, are divided into stromal and
pigment epithelial cysts [1 ]. Primary stromal cysts are
less common and mostly congenital [2]. Their differen-
tial diagnosis from malignant uveal melanoma may
sometimes be difficult. Primary cysts are of neuroepi-
thelial origin, whereas secondary cysts may result from
intraocular implantation of surface epithelium following
surgery or a penetrating trauma, or else from metastasis,
parasites, or chronic myotic therapy [3]. Neuroepithelial
cysts involve the iris pigment epithelium (IPE) and the
ciliary bod y [4].
Primary cysts of the IPE are uncommon and sponta-
neous. T hey are defined as epithelial-lined struc tur es t hat
arise in t he poster ior iris layer [ 5 ] . Shields (1981) distin-
guishes four t ypes, according to their po sition in rela tion
to the iris [1]: c entral, at the pupillar y mar gin; midzonal,
between the pupillary margin and the iris roo t; peripheral,
at the iridociliary sulcus; dislodged, in the anterior
chamber or the vitreous cavity. The vast majority (76%)
is peripheral [1].
This paper describes a case of symptomatic primary
central IPE cyst initially mistaken for an iris melanoma.
Stress is laid on ultrasound biomicroscopy (UBM) as a
noninvasive way of determining the nature of a cyst,
establishing its final diagnosis and following its course.
2. Case Report
A 63-year-old man presented with a two-month history
of disturbed vision in his left eye and a suspected iris
melanoma. In distant vision, his best corrected visual
acuity (BCVA) was 20/20 in both eyes, but his left-eye
disturbance was aggravated by strong daylight, which
caused a severe temporary deterioration of vision (
20/50). Slit-lamp examination showed a solitary, homo-
geneously pigmented mass hanging at the superior pu-
pillary margin of the iris and at 1 o’clock in the anterior
chamber (Figure 1). It slowly moved when the patient
changed the position of his head. It was smooth,
dark-brown and apparently cystic. The pupil was round,
readily reacting to light and accomodation. During mi-
osis, the lesion often obstructed the pupillary aperture.
The slit lamp also revealed a normal left external eye,
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cornea and conjunctiva, both before and after papilla ry
dilatation, with no signs of inflammation in the anterior
chamber. The right eye was normal. Examination with a
Goldmann goniolens disclosed normal angular structures
in both eyes. A Gold mann ap planation tonometer sho wed
an intraocular pressure of 14 mmHg in each eye. The
fundi oculi were unexceptional. UBM of each eye was
performed with a Humphrey 840 instrument, using a 50
MHz probe and an immersion technique. An immersion
scleral shell was placed on the globe between the eyelids
and filled with 2% methylcellulose. The probe was
moved at right angles to produce radial and transverse
sections. A 5 x 5 mm cyst with a thin, mediu m re flective
wall and acoustically clear content (Figure 2) was ob-
served in the left eye. The patient was dul y informed that
his cyst could be removed or kept under regular observa-
He chose surgery because of his disturbing visual
Figure 1. Solitary, dark-brow n cyst in the supero-temporal
aspect of t he p upillary margin.
Figure 2. Ultrasound biomicroscopy of the left eye shows a
pigmented cyst with a thin, medium reflective wall and
acoustically clear contents, measuring 5.0 × 5.0 mm of di-
symptoms. Surgery was then performed under topical
anesthesia. A blade was used to make a 3-mm limbal
section, followed by controlled entry into the anterior
chamber. Do wnward ro tation of the globe resulted in the
spo ntaneous r upture and coll apse of the cyst. I t was the n
extruded through the limbal section (Fig ure 3). The
wound was closed with a single 10-0 monofilament ny-
lon suture. Transmission electron microscopy was used
to examine the structure of the wall (Figure 4). Histo-
logically, the iris simplex cyst is break off and partially
lined by are present (Figure 5). It was therefore classed
according to Shields [1] as a primary pupillary margin
IPE cyst. After surgery, topical 0.1% fluorometholone
was ad ministered 4 times a day. One week later, BCVA
was 20/20 in both dis tant a nd near vi sion. T he i ntraoc ular
Figure 3. As the globe was rotated downwards, the cyst
spontaneously ruptured, collapsed and was then extruded
out through t he li mb al se ction.
Figure 4 . Microvil lous pr oces sis are evident alo ng t he apical
port ions of t he cell s, con necting by occlu dens an d adherens
junctions. Small round or ovoid granules in early stages of
melanization are seen (TEM; original magnification 11500 x).
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Figure 5. Hi stopatholog ical ex amin ation of th e tissue sh ows
that it consists entirely of pigmented epithelium without
connective tissue or vascular el ements.
pressure, the shape of the anterior chamber and the reac-
tion of the pupil to light were normal.
3. Discussion
Primary IPE cysts are found anywhere along the post-
erior surface of the iris from the pupillary margin to the
anterior ciliary body. The great majority are stationary
and small, and sometimes regress spontaneously. Their
presence is occasionally responsible for angle closure
glaucoma, plateau iris syndrome and secondary pigment
dispersion syndrome. [6-9]. Central cysts account for
approximately 3% of all primary IPE cysts [1,5]. They
are usually dark brown, round or oval with a thin wall
and sonolucent contents [1-5 ] . The high reflectivity of
their wall is attributed to the epithelial cells, while their
sonolucent core is compatible with a fluid content. The
origin of primary central IPE cysts is not clear. Their
appearance in early childhood in a few familial cases
suggests that they may be hereditary with an autosoma l-
dominant pattern [7-10]. Lewis et al. [11] described an
association with familial aortic dissection. Sallo and
Hatvani [12] reported four cases of primary pupillary
IPE cysts in a single family. These patients also suffered
fro m transie nt vis ion d istur banc es. O ur pati ent, ho weve r,
had no history of associated systemic diseases and no
other membe r of hi s fa mi l y ha d a cyst . P r imar y I P E cysts
have often been misdiagnosed as iris or ciliary body me-
lanoma [13]. Cysts of the iris are more likely to be con-
fused with melanoma than those of ciliary body because
of their pigmentation and more anterior location. Diag-
nosis and monitoring of iris, ciliary body and posterior
chamber cysts require the imaging of structures not al-
ways visible with a slit lamp and go ni olens, even through
a dilated pupil. UBM has thus become indispensable for
evaluating anterior segment tumors and cysts and is used
to confirm a clinical diagnosis of primary IPE cysts, dif-
ferentiate them from cystic and solid tumors (iris-ciliary
body melanoma and melanocytoma, adenoma of the IPE
and medulloepithelioma), follow their course and
pro mptl y inte rvene i f s ur gery is r eq uir e d. I t al so p ro vid e s
cross-sectional images illustrating the surface contour,
internal reflectivity and borders, and reveals their size,
extension and site. Management is determined by a
cyst’s site, size, local extent and growth pattern, and the
presence of secondary complications. Most primary IPE
cysts run a benign clinical course that seldom results in
ocular complications. They are usually small and fre-
quently regress spontaneously. Those that arise from the
IPE layers are stationary, asymptomatic, and detected
only incide ntally. Shield s beli eves that most pri mary IPE
cysts are ophthalmic curiosities that need prolonged ob-
servation and no treatment [1]. A steadily growing cyst,
however, may disturb vision by covering the visual axis
and provoke an increase in intraocular pressure or even
inflammation i f it to uches t he cor neal endotheli u m. Steps
must then be taken to prevent or treat complications,
such as pupillary obstruction, secondary glaucoma, iri-
docyclitis, corneal decompensation and loss of vision.
Numerous forms of managements have been employed.
Mitomycin injection into the cyst and needle aspiration
with endodiathermy were proposed by Kawaguchi et al.
[14] and Tsai et al. [15]. Kuchenbecker et al. [16], Öner
et al. [17] and Baykara et al. [18] prefer Nd:YAG laser
cystotomy as the least invasive procedure. Excision in
our case, like in that reported by Verma et al. [19], was
dictated by the fact that in strong daylight the cyst ob-
scured the visual axis almost completely and caused a
severe temporary decrease of visual acuity. There were
no complications and no clinical or UBM evidence of
recurrences or fresh lesions during a one-year follow-up.
In conclusion, in agreement with most authors we be-
lieve that stable and asymptomatic primary IPE cysts
usual ly requi re no more than regular o bserva tion. P roper
treatment depends on the overall clinical picture, which
includes both the patient’s general health and the size
and location of the cyst. Lastly, the importance of early
diagnosis should be stressed. UBM is a useful, readily
available and noninvasive tool for this purpose, since it
can be employed to both confirm the clinical diagnosis
and follow the course of these cysts. We address future
studies on anterior chamber OCT to “in vivo” analyze
cyst morphology.
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Copyright © 2011 SciRes . CM
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