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OJHAS Vol. 10, Issue 2:
(Apr-Jun 2011) |
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| An Unusual
Melanocytic Nevus of Conjunctiva : Balloon Cell Nevus |
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Vijay Shankar S, Associate Professor, Department of Pathology,
Nischal
KC, Assistant Professor, Department of Dermatology,
Geethalakshmi
U, Assistant
Professor, Department of Pathology,
Padmini HR, Professor & Head, Department
of Ophthalmology,
Adichunchangiri Institute of Medical Sciences. B G Nagara. Nagamangala taluk, Mandya
district, Karnataka. |
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Address for Correspondence |
No 45, Ananda
shylam, 3rd cross,
1st
main KN extension, Yeswanthpur,
Bangalore
- 560022,
Karnataka, India.
E-mail:
vijayshankarpatho@gmail.com |
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Vijay Shankar S, Nischal KC, Geethalakshmi U, Padmini HR. An Unusual Melanocytic Nevus of Conjunctiva : Balloon Cell Nevus. Online J Health Allied Scs.
2011;10(2):23 |
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Submitted: May 8,
2011; Accepted: Jul 15, 2011; Published: Jul 30, 2011 |
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| Abstract: |
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Melanocytic
nevi are one of the most common benign tumors of the conjunctiva. The
balloon cell nevus is a rare and unusual variant of nevus of melanocytic
origin, in which more than 50% of the tumor is composed of large polygonal
cells with small nucleus and a clear to vacuolated cytoplasm. We describe
a case of balloon cell nevus in a 6-year-old child who presented with
pigmented lesion of the right eye since birth. The melanocytic nature
of these cells was confirmed by immunohistochemical study. Excision
of the tumor results in cure. This report describes a rare balloon cell
nevus of conjunctiva which to the best of our knowledge is not documented
in Indian literature.
Key Words:
Nevi; Balloon cell; Conjunctiva
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Melanocytic
nevi of conjunctiva are the common benign tumors on the ocular surface.
Nevi are usually congenital and generally are unilateral. Conjunctival
nevi can be intraepithelial, subepithelial or compound nevi which are
analogous to junctional, intradermal and compound nevi of skin.1
Spitz nevi, epitheloid nevi, combined nevi, dysplastic nevi, balloon
cell nevi, recurrent nevi, nevus of Ota and blue nevi accounts for a
wide variety of unusual nevi in conjunctiva.2 Melanocytic
nevi with balloon cell change are an uncommon feature in nevi involving
skin and such a change in conjunctival nevi is even rarer.
A 6-year-old
boy presented with an asymptomatic brownish flat lesion on the right
eye since birth. On examination, a single, well defined, slightly elevated,
brownish, movable plaque of 4 mm x 3 mm was noted in the bulbar conjunctiva
close to the temporal limbus of the right eye (Figure 1). Fornices,
tarsus and cornea of both eyes were normal. The lesion was excised under
general anaesthesia and sent for histopathological examination. There
was no recurrence of the lesion during 6 months of follow up.
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Figure 1:
Right eye showing single, brownish elevation in the bulbar
conjunctiva in the lateral aspect. |
On histology,
the lesion showed normal epithelium with diffuse distribution of predominantly
vacuolated cells beneath it. (Figure 2). These cells were polyhedral
in shape with small, hyperchromatic nuclei and a clear to microvesicular
cytoplasm (Figure 3). No mitotic figures were seen. Nests of nevus cells
were also seen subepithelially, at the edge of the lesion. Scattered
melanophages were seen throughout the tumor along with chronic inflammatory
cell infiltrates. Immunohistochemistry revealed positivity for S 100
protein (Figure 3, inset) confirming the diagnosis of balloon cell nevus.
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| Figure 2: Excisional
biopsy revealed diffuse distribution of predominantly balloon cells
beneath the normal conjunctiva. Interspersed amongst these are normal
nevus cells, melanophages and scattered chronic inflammatory cells (H
and E stain, x100) |
Figure 3: Higher magnification
reveals balloon cells which are polyhedral cells with small, hyperchromatic
round nuclei and clear to microvesicular cytoplasm (H and E stain, x400).
Inset shows these cells positive for S 100 protein (x400) |
The conjunctiva
is a thin continuous mucus membrane lining the inner surface of the
eyelids and most of the anterior aspect of eye, is composed of 2 to
5 layers of stratified columnar epithelium. Melanocytes are present
in the basal layers and like in skin, can transfer melanosomes to the
adjacent epithelial cells.
Thus conjunctiva can be a site of many melanocytic lesions. The most
common ones are nevi which are benign.
These are often single, freely movable and most common in juxtalimbal
area followed by epibulbar, plica, caruncle, eyelid margin forniceal
conjunctiva.3 Multifocality is less common. Balloon
cell nevus of conjunctiva is an uncommon melanocytic nevus with no distinct
clinical morphology. They can occur in any age group of 11 to 39 years
as documented in the various reported cases. They are often brown to
tan yellow in color. Clinically, balloon cell nevus has to be
differentiated from blue nevus, Spitz nevus, combined nevus, dysplastic
nevus, benign melanosis and acquired primary melanosis.
As there
is no distinct clinical feature for this nevus, the diagnosis is only
by histopathological examination. The nevus cells of this variant are
typified by the presence of balloon cells constituting more than 50%
of the tumor.4 These cells are large, polygonal cells with
small hyperchromatic nuclei and abundant clear to microvesicular cytoplasm.
The ballooning of these cells is due to the collection of malformed
vesicular premelanosomes.
Kim et al also suggested that apoptosis could be involved in
the development of balloon cell nevus.5
Nests of nevus cells can also be seen beneath the conjunctival epithelium
or at the lateral margins of the tumor. Balloon cells histologically
can be confused with xanthoma cells, hibernoma cells, and other clear
cell tumors like clear cell hidradenoma, clear cell sarcoma or a metastatic
renal cell carcinoma. Therefore it is necessary to confirm the melanocytic
nature of balloon cells either by immunohistochemistry or electron microscopy.
Balloon cells stain positive for S 100 protein and other melanocyte
markers like melan A/ MART – 1, but negative with HMB-45. Our case
showed cytoplasmic positivity for S-100 protein. Ultrastructurally,
balloon cells show intracytoplasmic vacuoles of various sizes and melanosomes
that are microgranular and vacuolated.
Balloon cell change in melanomas can be identified by the pleomorphic
nature of melanoma cells.
The balloon
cell nevus is an unusual variant of nevus of melanocytic origin
and its occurrence in conjunctiva is rare. It has no characteristic
clinical morphology and the diagnosis is based solely on histopathological
examination which should be confirmed by immunohistochemical reaction
with melanocyte markers. However it is also of importance to clinicians
as malignant melanoma is one of the differential diagnosis which is
of greater concern which although rare, can occur in children.
- Rodriguez-Sains
RS. Pigmented conjunctival neoplasms. Orbit 2002;21:231-238.
- Jakobiec FA, Zuckerman
BD, Berlin AJ, Odell P, MacRae DW, Tuthill RJ. Unusual melanocytic nevi
of the conjunctiva. Am J Ophthalmol 1985;100:100-113.
- Farber M, Schutzer
P, Mihm MC Jr. Pigmented lesions of the conjunctiva. J Am Acad Dermatol 1998;38:971-978.
- Melanocytic nevi.
In, McKee P, Calonje E, Granter S (editors). Pathology of the skin with
clinical correlations, 3rd edition. Philadelphia, Mosby, 2005. pp 1265-66.
- Kim YJ, Kim YC,
Kang HY. Is apoptosis involved in the development of balloon cell nevus?
Suggestion from a case report. J Am Acad Dermatol 2007;56:1069-1070.
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