Phakomatous Choristoma
of the Eyelid
Immunohistochemical and Electron Microscopic Observations 1 2 Pearl S. Rosenbaum, MD, 1•2 Yvonne Kress, MS, Thomas L. Slamovits, MD, 3 Ramon L. Font, MD
Background: A 13-month-old Hispanic boy underwent excision of a congenital in feronasal orbital mass arising from the right lower lid. Results of histopathologic ex amination of the tumor showed a phakomatous choristoma of the eyelid. An immuno histochemical and electron microscopic study of this rare, benign, congenital tumor of lenticular anlage was performed. Methods: Immunohistochemistry was performed on 4-~Jm thick sections from par affin-embedded tissue. Electron microscopy was performed on thin sections stained with uranyl acetate and lead citrate. Findings: The cuboidal epithelial cells that comprise this choristoma showed strongly positive cytoplasmic staining with S-1 00 protein and vimentin and focally positive staining with a keratin cocktail (AE 1/AE 3 ). Electron microscopy showed the presence of numerous 10-nm whorled cytoplasmic microfilaments within degenerating epithelial cells. Conclusion: The immunoreactivity of this tumor to keratin and vimentin are newly described in this detailed clinicopathologic report and , together with its S-1 00 positivity, support the proposal that this tumor is of lenticular anlage. The authors hypothesize that the intracytoplasmic 10-nm intermediate filaments observed with electron micro scopic examination within the epithelial cells that comprise this choristoma represent vimentin as detected by immunohistochemistry. Ophthalmology 1992;99:1779-1784
Originally received: March 23, 1992. Revision accepted: July 23, 1992. 1 Department ofOphthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx. 2
Department of Pathology, Albert Einstein College of Medicine, Bronx.
Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston. 3
Presented at the 29th Eastern Ophthalmic Pathology Society Meeting, New Providence, The Bahamas, Nov/Dec 1990. Supported in part by an unrestricted departmental grant to the Depart ment of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Montefiore Medical Center from Research to Prevent Blind ness, Inc, New York, New York, and in part by grants from the Retina Research Foundation and the Lions Eye Bank, Houston, Texas. Reprint requests to Pearl S. Rosenbaum, MD, Department of Ophthal mology and Visual Sciences, Montefiore Medical Center, Ill E 21 Oth St, Bronx, NY 10467-2490.
Phakomatous choristoma of the eyelid is a rare, benign, congenital tumor of lenticular anlage. Zimmerman 1 first described and named this tumor in 1971 based on his observations of three cases studied at the Armed Forces Institute of Pathology. The embryologic pathogenesis of this tumor is intrigu ing. Zimmerman hypothesized that this tumor in the lower lid is derived from an unknown stimulus that in duces the "surface ectoderm to dip down into the me soderm of the eyelid, just as the optic vesicle normally induces the surface ectoderm to invaginate to form the lens vesicle." ' Tripathi et al 2 postulated that cells derived from the inferior aspect of the lens placode or stalk migrate through the patent embryonic choroidal fissure ofthe optic vesicle located ventronasally to give rise to this tumor, characteristically located in the nasal portion of the lower eyelid. McMahon et aV observing that all of the cases of
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Volume 99, Number 12, December 1992
phakomatous choristoma developed in the lower eyelid nasally, suggested that the site in the surface ectoderm from which the lens normally invaginates is destined to form the lower lid near the inner canthus. The purpose of this report is to document a case of phakomatous choristoma, including immunohistochem ical and electron microscopic observations.
Case Report A 2-month-old Hispanic boy was first examined for a narrowed interpalpebral fissure of the right eye. The child, who weighed 7 lb, 8 oz at birth, was the product of a full-term pregnancy. The child's mother abused cocaine. A swelling ofthe right lower eyelid was noted at birth. At his initial ophthalmologic evalua tion, a firm, mobile, 8-mm nodule adjacent to the inferior orbital rim nasally was palpated. The right globe was displaced superiorly and temporally, and there was marked anisometropia due to a mixed hyperopic astigmatism. The child was examined peri odically over the ensuing months. At 13 months of age, the child fixated and followed in both eyes. The patient's cycloplegic refraction was +5.00 -6.00 X 15 ° on the right and +2.00 sphere on the left. The firm orbital mass had enlarged, now measuring 15.0 X 10.0 mm. Displace ment of the right globe persisted. The results of ophthalmologic examination were otherwise unremarkable. Computed axial to mography of the orbits demonstrated a solid, extraconal, soft tissue mass with areas of calcification in the inferonasal portion of the right lower lid and orbit (Fig 1). A radiologic diagnosis of dermoid cyst was made. Because of the induced anisometropia and the gradual en largement of the tumor, the patient underwent a right inferior orbitotomy and the mass was excised in toto. Intraoperatively, the tumor was found to be firmly adherent to the right lower lid, nasally. Three weeks after surgery, there was symmetry of the eyelids and globes, as well as marked resolution of the anisometropia.
Pathologic Findings On gross examination, a firm, tan, spherical mass mea suring 17 X 15 X 9 mm was observed. The cut surface
Figure 1. Coronal view of computed tomogram of the orbits shows a round, well-circumscribed mass with foci of calcification in the right lower lid and orbit inferonasally.
was solid and smooth, and showed a faint reticular pattern of white bands surrounding ovoid, tan areas (Fig 2). Microscopically, epithelial islands composed of double layered cords and single-layered tubules of predominantly
Top left, Figure 2. The cut surface of the tumor is solid and smooth with a faint reticular pattern of white bands of collagenous tissue surrounding ovoid, tan areas with few hemorrhagic foci. Top right, Figure 3. Tubular structure containing degenerated eosinophilic material is lined by a single layer of cuboidal cells and surrounded by a thick wrinkled basement membrane (hematoxylin-eosin; original magnification, X100). Second row left, Figure 4. Some epithelial cells within the tubules display swollen cytoplasm with small eccentric nuclei that resemble the "bladder cells of Wed!" seen in human cataractous lenses. Granular degenerated material with irregular calcific deposits also are present (hematoxylin-eosin; original magnification, X64). Second row right, Figure 5. Adjacent section to that seen in figure 4 depicting epithelial islands containing granular eosinophilic material and cellular debris with foci of dystrophic calcification. An irregular thickened basement membrane with numerous infoldings surround the islands (periodic acid Schiff; original magnification, X51). Third row left, Figure 6. Solid epithelial islands displaying positive cytoplasmic staining with S-100 protein (avidin-biotin complex method, hematoxylin counterstain; original magnification, X80). Third row right, Figure 7. The epithelial islands show strong cytoplasmic immunoreactivity to vimentin (avidin-biotin complex method, hematoxylin counterstain; original magnification, X80). Bottom, Figure 8. Large, coarse melanin pigment granules are present within the cytoplasm of several epithelial cells. Adjacent epithelial cells display S-100 positivity (avidin-biotin complex method, hematoxylin counterstain; original magnification, X 100).
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Rosenbaum et al · Phakomatous Choristoma of the Eyelid
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Volume 99, Number 12, December 1992
cuboidal cells with round, centrally located nuclei were embedded within a dense collagenous stroma. The epi thelial elements often formed glandular structures that contained an amorphous, eosinophilic, globular secretion. Some of the epithelial cells appeared ballooned (so-called "Bladder cells of Wedl"). Numerous foci of dystrophic calcification were present within the epithelial structures. The epithelial structures were surrounded by thick, irreg ular fragments of basement membrane material, which often invaginated among individual epithelial cells (Figs 3-5).The collagenous stroma was rich in hyaluronidase sensitive mucopolysaccharides, as evidenced by the col loidal iron stain with and without hyaluronidase digestion. Immunohistochemistry was performed on 4-t~m thick sections from paraffin-embedded tissue. The epithelial tubules stained markedly positive with S-100 protein and vim en tin, and focally positive with a keratin cocktail (AEd AE 3) (Figs 6 and 7). Additionally, on glass slides stained
Figure 10. The plasmalemmas of the adjacent epithelial cells are focally joined by desmosomes (arrowheads). Cytoplasmic organelles consist pre dominantly of short segments of rough-surfaced endoplasmic reticulum (arrows) and numerous cytoplasmic filaments (F) (transmission electron micrograph; original magnification, X8000).
with S-1 00 protein, large, coarse, dark brown melanin pigment granules were observed within the cytoplasm of several epithelial cells adjacent to epithelial cells disclosing S-100 positivity (Fig 8). Electron microscopy was performed on thin sections stained with uranyl acetate and lead citrate. Cuboidal ep ithelial cells with interdigitating plasmalemmas, focally joined by desmosomes, rested on thick bands of homo geneous basement membrane (Fig 9). The cytoplasmic organelles were generally sparse, consisting predominantly of short segments of rough-surfaced endoplasmic reticu lum and scattered clusters ofpolyribosomes (Fig 10). Nu merous degenerated epithelial cells displayed amorphous globular material, cytoplasmic vacuolization, and dilated cisternae of rough-surfaced endoplasmic reticulum. Some cells, most of which were located in the center of the ep ithelial structures, contained numerous 10-nm whorled cytoplasmic microfilaments (Fig 9). We hypothesize that these 10-nm intermediate filaments represent vim entin as detected by immunohistochemistry.
Discussion
Figure 9. Transmission electron micrograph of an epithelial tubule shows rather well-preserved cuboidal epithelial cells (E) resting on a thick, ho mogeneous basement membrane (BM). An ill-defined lumen (L) is ob served toward the center of the epithelial structure which contains de generated epithelial cell processes with cytoplasmic vacuolization and cytoplasmic microfilaments (original magnification X3,000). Inset shows whorls. of cytoplasmic microfilaments (F) (original magnification, XlO,OOO).
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A total of 10 cases of phakomatous choristoma of the eyelid have been reported previously (Table 1); 2 of these cases were reported in Australia, 1 in Europe, 1 in South Africa, and the remainder in the United States. 1- 8 Eight patients were boys and two were girls. All the patients were first seen in early infancy with a firm mass involving the nasal portion of the lower eyelid; the right and left lower lids were involved with equal frequency. In all cases, the results of ophthalmologic examination were otherwise unremarkable. The most frequent preoperative clinical diagnosis was dermoid cyst, as in our case. Surgical ex cisions of the tumors were performed within the first 6
Rosenbaum et al · Phakomatous Choristoma of the Eyelid
Table 1. Summary of Reported Cases of Phakomatous Choristoma of the Eyelid Case No. (Reference) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.
1
(Zimmerman, 1971) (Zimmerman, 1971) 1 (Zimmerman, 1971)1 (Filipic and Silva, 1972)4 (Greer, 197W (McMahon et al, 1976)3 (Baggesen and Jensen, 1977)6 (Tripathi et al, 1981)2 (Sinclair-Smith et al, 1989)1 (Eustis et al, 1990)8 (Rosenbaum et al, 1992) (current study)
Age at Time of Surgery
Sex
Laterality
Size of Mass
10 wks* 6 mos 2 wkst 5 mos 4 mos 4mos 5 mos 5 mos 4mos 4 mos
M M M F M M F M M M
Right Right Right Right Left Left Left Left Left Right
Not stated 10mm 12 X 7 mm 16 X 6 mm 12 X 10 X 6 mm 12 X 10 X 7 mm Not stated Not stated 15 X 10 X 10 mm 14 X 11 X 7 mm
13 mos
M
Right
17 X 15 X 9 mm
*Incomplete surgical excision; no recurrence or residual tumor at 7 112 years of age.
t
Incomplete surgical excision; no recurrence or residual tumor at approximately 16 months of age.
months of life in all cases. In 2 of the 10 previously re ported cases, the tumor was incompletely excised; 1 these 2 children were followed until 7 1h years of age and ap proximately 16 months of age without evidence of recur rent or residual tumor or ocular abnormality. These ob servations emphasize the benign clinical nature of this tumor. Our case represents the eleventh reported case of phak omatous choristoma, excised from the right lower lid and inferonasal orbit of a 13-month-old boy. Our patient was older at the time of surgical excision ( 13 months) and the tumor was larger ( 17 mm in maximal diameter) than in the cases previously reported. The lid mass displayed the typical histopathologic and electron microscopic features previously described. '- 5•7 •8 Essentially, this choristoma is composed of degenerated lens epithelium, displaying histologic features similar to those observed in various stages of cataract formation. Zimmerman' noted that the collagenous connective tissue stroma of the tumor is rich in mucopolysaccharides. We were able to confirm this finding and, also, show that the mucopolysaccharide is rich in hyaluronic acid. The immunoreactivity of phakomatous choristoma to keratin and vimentin are newly described. Focal cyto plasmic staining of the epithelial cells with a keratin cock tail (AEt/AE 3 ) reflects their origin from the surface ec toderm. The reaction to S-100 protein is strongly positive, 7 as we have found previously in normal lens epithelium as well as in the epithelial cells ofSoemmering's ring cat aract. The immunoreactivity to vimentin, the major in termediate filament that occurs in vertebrate lens epithelial cells, 9 supports the lenticular origin of this choristoma. Furthermore, the strong diffuse positive staining with vi
mentin correlates well with the presence of numerous 10 nm cytoplasmic filaments as observed by electron mi croscopy. In our case, coarse, dark brown pigment granules were noted within the cytoplasm of several epithelial cells on slides stained with S-1 00 protein. These pigment granules are large and histopathologically resemble those of the retinal pigment epithelium. This finding supports the the ory of pathogenesis provided by Tripathi et al, 2 whereby primitive neuroectodermal cells, in the region ofthe patent embryonic choroidal fissure of the optic vesicle, may be come entrapped among the migrating cells derived from the lens placode or stalk. We also learned of an unpub lished case of phakomatous choristoma, which involved the right lower lid of a 6-month-old boy, displaying similar melanotic pigmentation of some of the epithelial cells (personal communication; Pearl S. Rosenbaum, MD, Norman C. Charles, MD). In the latter case, the pigment granules stained positive for melanin and negative for iron. Phakomatous choristoma of the eyelid should be in cluded in the clinical differential diagnosis of congenital tumors involving the nasal aspect of the lower lid.
References 1. Zimmerman LE. Phakomatous choristoma of the eyelid, a tumor of lenticular anlage. Am J Ophthalmol 1971 ;71: 169 77. 2. Tripathi RC, Tripathi BJ, Ringus J. Phakomatous choris toma of the lower eyelid with psammoma body formation. A light and electron microscopic study. Ophthalmology 1981 ;88: 1198-1206.
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Volume 99, Number 12, December 1992
3. McMahon RT, Font RL, McLean IW. Phakomatous chor istoma ·of eyelid. Electron microscopical confirmation of lenticular derivation. Arch Ophthalmol 1976;94: 1778-81. 4. Filipic M, Silva M. Phakomatous choristoma of the eyelid. Arch Ophthalmol 1972;88: 172-5. 5. Greer CH. Phakomatous choristoma in the eyelid. Aust J Ophthalmol 1975;3:106-7. 6. Baggesen LH, Jensen OA. Phakomatous choristoma oflower eyelid: a lenticular anlage tumour. Ophthalmologica 1977;175:231-5.
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7. Sinclair-Smith CC, Emms M, Morris HB. Phakomatous choristoma of the lower eyelid. A light and ultrastructural study. Arch Pathol Lab Med 1989;113:1175-7. 8. Eustis HS, Karcioglu ZA, Dharma S, Hoda S. Phakomatous choristoma: clinical, histopathologic, and ultrastructural findings in a 4-month-old boy. J Pediatr Ophthalmol Stra bismus 1990;27:208-11. 9. Bloemendal H. Disorganization of membranes and abnor mal intermediate filament assembly lead to cataract. Invest Ophthalmol Vis Sci 1991 ;32:445-55.
of the Eyelid
Immunohistochemical and Electron Microscopic Observations 1 2 Pearl S. Rosenbaum, MD, 1•2 Yvonne Kress, MS, Thomas L. Slamovits, MD, 3 Ramon L. Font, MD
Background: A 13-month-old Hispanic boy underwent excision of a congenital in feronasal orbital mass arising from the right lower lid. Results of histopathologic ex amination of the tumor showed a phakomatous choristoma of the eyelid. An immuno histochemical and electron microscopic study of this rare, benign, congenital tumor of lenticular anlage was performed. Methods: Immunohistochemistry was performed on 4-~Jm thick sections from par affin-embedded tissue. Electron microscopy was performed on thin sections stained with uranyl acetate and lead citrate. Findings: The cuboidal epithelial cells that comprise this choristoma showed strongly positive cytoplasmic staining with S-1 00 protein and vimentin and focally positive staining with a keratin cocktail (AE 1/AE 3 ). Electron microscopy showed the presence of numerous 10-nm whorled cytoplasmic microfilaments within degenerating epithelial cells. Conclusion: The immunoreactivity of this tumor to keratin and vimentin are newly described in this detailed clinicopathologic report and , together with its S-1 00 positivity, support the proposal that this tumor is of lenticular anlage. The authors hypothesize that the intracytoplasmic 10-nm intermediate filaments observed with electron micro scopic examination within the epithelial cells that comprise this choristoma represent vimentin as detected by immunohistochemistry. Ophthalmology 1992;99:1779-1784
Originally received: March 23, 1992. Revision accepted: July 23, 1992. 1 Department ofOphthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx. 2
Department of Pathology, Albert Einstein College of Medicine, Bronx.
Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston. 3
Presented at the 29th Eastern Ophthalmic Pathology Society Meeting, New Providence, The Bahamas, Nov/Dec 1990. Supported in part by an unrestricted departmental grant to the Depart ment of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Montefiore Medical Center from Research to Prevent Blind ness, Inc, New York, New York, and in part by grants from the Retina Research Foundation and the Lions Eye Bank, Houston, Texas. Reprint requests to Pearl S. Rosenbaum, MD, Department of Ophthal mology and Visual Sciences, Montefiore Medical Center, Ill E 21 Oth St, Bronx, NY 10467-2490.
Phakomatous choristoma of the eyelid is a rare, benign, congenital tumor of lenticular anlage. Zimmerman 1 first described and named this tumor in 1971 based on his observations of three cases studied at the Armed Forces Institute of Pathology. The embryologic pathogenesis of this tumor is intrigu ing. Zimmerman hypothesized that this tumor in the lower lid is derived from an unknown stimulus that in duces the "surface ectoderm to dip down into the me soderm of the eyelid, just as the optic vesicle normally induces the surface ectoderm to invaginate to form the lens vesicle." ' Tripathi et al 2 postulated that cells derived from the inferior aspect of the lens placode or stalk migrate through the patent embryonic choroidal fissure ofthe optic vesicle located ventronasally to give rise to this tumor, characteristically located in the nasal portion of the lower eyelid. McMahon et aV observing that all of the cases of
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Ophthalmology
Volume 99, Number 12, December 1992
phakomatous choristoma developed in the lower eyelid nasally, suggested that the site in the surface ectoderm from which the lens normally invaginates is destined to form the lower lid near the inner canthus. The purpose of this report is to document a case of phakomatous choristoma, including immunohistochem ical and electron microscopic observations.
Case Report A 2-month-old Hispanic boy was first examined for a narrowed interpalpebral fissure of the right eye. The child, who weighed 7 lb, 8 oz at birth, was the product of a full-term pregnancy. The child's mother abused cocaine. A swelling ofthe right lower eyelid was noted at birth. At his initial ophthalmologic evalua tion, a firm, mobile, 8-mm nodule adjacent to the inferior orbital rim nasally was palpated. The right globe was displaced superiorly and temporally, and there was marked anisometropia due to a mixed hyperopic astigmatism. The child was examined peri odically over the ensuing months. At 13 months of age, the child fixated and followed in both eyes. The patient's cycloplegic refraction was +5.00 -6.00 X 15 ° on the right and +2.00 sphere on the left. The firm orbital mass had enlarged, now measuring 15.0 X 10.0 mm. Displace ment of the right globe persisted. The results of ophthalmologic examination were otherwise unremarkable. Computed axial to mography of the orbits demonstrated a solid, extraconal, soft tissue mass with areas of calcification in the inferonasal portion of the right lower lid and orbit (Fig 1). A radiologic diagnosis of dermoid cyst was made. Because of the induced anisometropia and the gradual en largement of the tumor, the patient underwent a right inferior orbitotomy and the mass was excised in toto. Intraoperatively, the tumor was found to be firmly adherent to the right lower lid, nasally. Three weeks after surgery, there was symmetry of the eyelids and globes, as well as marked resolution of the anisometropia.
Pathologic Findings On gross examination, a firm, tan, spherical mass mea suring 17 X 15 X 9 mm was observed. The cut surface
Figure 1. Coronal view of computed tomogram of the orbits shows a round, well-circumscribed mass with foci of calcification in the right lower lid and orbit inferonasally.
was solid and smooth, and showed a faint reticular pattern of white bands surrounding ovoid, tan areas (Fig 2). Microscopically, epithelial islands composed of double layered cords and single-layered tubules of predominantly
Top left, Figure 2. The cut surface of the tumor is solid and smooth with a faint reticular pattern of white bands of collagenous tissue surrounding ovoid, tan areas with few hemorrhagic foci. Top right, Figure 3. Tubular structure containing degenerated eosinophilic material is lined by a single layer of cuboidal cells and surrounded by a thick wrinkled basement membrane (hematoxylin-eosin; original magnification, X100). Second row left, Figure 4. Some epithelial cells within the tubules display swollen cytoplasm with small eccentric nuclei that resemble the "bladder cells of Wed!" seen in human cataractous lenses. Granular degenerated material with irregular calcific deposits also are present (hematoxylin-eosin; original magnification, X64). Second row right, Figure 5. Adjacent section to that seen in figure 4 depicting epithelial islands containing granular eosinophilic material and cellular debris with foci of dystrophic calcification. An irregular thickened basement membrane with numerous infoldings surround the islands (periodic acid Schiff; original magnification, X51). Third row left, Figure 6. Solid epithelial islands displaying positive cytoplasmic staining with S-100 protein (avidin-biotin complex method, hematoxylin counterstain; original magnification, X80). Third row right, Figure 7. The epithelial islands show strong cytoplasmic immunoreactivity to vimentin (avidin-biotin complex method, hematoxylin counterstain; original magnification, X80). Bottom, Figure 8. Large, coarse melanin pigment granules are present within the cytoplasm of several epithelial cells. Adjacent epithelial cells display S-100 positivity (avidin-biotin complex method, hematoxylin counterstain; original magnification, X 100).
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Rosenbaum et al · Phakomatous Choristoma of the Eyelid
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Ophthalmology
Volume 99, Number 12, December 1992
cuboidal cells with round, centrally located nuclei were embedded within a dense collagenous stroma. The epi thelial elements often formed glandular structures that contained an amorphous, eosinophilic, globular secretion. Some of the epithelial cells appeared ballooned (so-called "Bladder cells of Wedl"). Numerous foci of dystrophic calcification were present within the epithelial structures. The epithelial structures were surrounded by thick, irreg ular fragments of basement membrane material, which often invaginated among individual epithelial cells (Figs 3-5).The collagenous stroma was rich in hyaluronidase sensitive mucopolysaccharides, as evidenced by the col loidal iron stain with and without hyaluronidase digestion. Immunohistochemistry was performed on 4-t~m thick sections from paraffin-embedded tissue. The epithelial tubules stained markedly positive with S-100 protein and vim en tin, and focally positive with a keratin cocktail (AEd AE 3) (Figs 6 and 7). Additionally, on glass slides stained
Figure 10. The plasmalemmas of the adjacent epithelial cells are focally joined by desmosomes (arrowheads). Cytoplasmic organelles consist pre dominantly of short segments of rough-surfaced endoplasmic reticulum (arrows) and numerous cytoplasmic filaments (F) (transmission electron micrograph; original magnification, X8000).
with S-1 00 protein, large, coarse, dark brown melanin pigment granules were observed within the cytoplasm of several epithelial cells adjacent to epithelial cells disclosing S-100 positivity (Fig 8). Electron microscopy was performed on thin sections stained with uranyl acetate and lead citrate. Cuboidal ep ithelial cells with interdigitating plasmalemmas, focally joined by desmosomes, rested on thick bands of homo geneous basement membrane (Fig 9). The cytoplasmic organelles were generally sparse, consisting predominantly of short segments of rough-surfaced endoplasmic reticu lum and scattered clusters ofpolyribosomes (Fig 10). Nu merous degenerated epithelial cells displayed amorphous globular material, cytoplasmic vacuolization, and dilated cisternae of rough-surfaced endoplasmic reticulum. Some cells, most of which were located in the center of the ep ithelial structures, contained numerous 10-nm whorled cytoplasmic microfilaments (Fig 9). We hypothesize that these 10-nm intermediate filaments represent vim entin as detected by immunohistochemistry.
Discussion
Figure 9. Transmission electron micrograph of an epithelial tubule shows rather well-preserved cuboidal epithelial cells (E) resting on a thick, ho mogeneous basement membrane (BM). An ill-defined lumen (L) is ob served toward the center of the epithelial structure which contains de generated epithelial cell processes with cytoplasmic vacuolization and cytoplasmic microfilaments (original magnification X3,000). Inset shows whorls. of cytoplasmic microfilaments (F) (original magnification, XlO,OOO).
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A total of 10 cases of phakomatous choristoma of the eyelid have been reported previously (Table 1); 2 of these cases were reported in Australia, 1 in Europe, 1 in South Africa, and the remainder in the United States. 1- 8 Eight patients were boys and two were girls. All the patients were first seen in early infancy with a firm mass involving the nasal portion of the lower eyelid; the right and left lower lids were involved with equal frequency. In all cases, the results of ophthalmologic examination were otherwise unremarkable. The most frequent preoperative clinical diagnosis was dermoid cyst, as in our case. Surgical ex cisions of the tumors were performed within the first 6
Rosenbaum et al · Phakomatous Choristoma of the Eyelid
Table 1. Summary of Reported Cases of Phakomatous Choristoma of the Eyelid Case No. (Reference) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.
1
(Zimmerman, 1971) (Zimmerman, 1971) 1 (Zimmerman, 1971)1 (Filipic and Silva, 1972)4 (Greer, 197W (McMahon et al, 1976)3 (Baggesen and Jensen, 1977)6 (Tripathi et al, 1981)2 (Sinclair-Smith et al, 1989)1 (Eustis et al, 1990)8 (Rosenbaum et al, 1992) (current study)
Age at Time of Surgery
Sex
Laterality
Size of Mass
10 wks* 6 mos 2 wkst 5 mos 4 mos 4mos 5 mos 5 mos 4mos 4 mos
M M M F M M F M M M
Right Right Right Right Left Left Left Left Left Right
Not stated 10mm 12 X 7 mm 16 X 6 mm 12 X 10 X 6 mm 12 X 10 X 7 mm Not stated Not stated 15 X 10 X 10 mm 14 X 11 X 7 mm
13 mos
M
Right
17 X 15 X 9 mm
*Incomplete surgical excision; no recurrence or residual tumor at 7 112 years of age.
t
Incomplete surgical excision; no recurrence or residual tumor at approximately 16 months of age.
months of life in all cases. In 2 of the 10 previously re ported cases, the tumor was incompletely excised; 1 these 2 children were followed until 7 1h years of age and ap proximately 16 months of age without evidence of recur rent or residual tumor or ocular abnormality. These ob servations emphasize the benign clinical nature of this tumor. Our case represents the eleventh reported case of phak omatous choristoma, excised from the right lower lid and inferonasal orbit of a 13-month-old boy. Our patient was older at the time of surgical excision ( 13 months) and the tumor was larger ( 17 mm in maximal diameter) than in the cases previously reported. The lid mass displayed the typical histopathologic and electron microscopic features previously described. '- 5•7 •8 Essentially, this choristoma is composed of degenerated lens epithelium, displaying histologic features similar to those observed in various stages of cataract formation. Zimmerman' noted that the collagenous connective tissue stroma of the tumor is rich in mucopolysaccharides. We were able to confirm this finding and, also, show that the mucopolysaccharide is rich in hyaluronic acid. The immunoreactivity of phakomatous choristoma to keratin and vimentin are newly described. Focal cyto plasmic staining of the epithelial cells with a keratin cock tail (AEt/AE 3 ) reflects their origin from the surface ec toderm. The reaction to S-100 protein is strongly positive, 7 as we have found previously in normal lens epithelium as well as in the epithelial cells ofSoemmering's ring cat aract. The immunoreactivity to vimentin, the major in termediate filament that occurs in vertebrate lens epithelial cells, 9 supports the lenticular origin of this choristoma. Furthermore, the strong diffuse positive staining with vi
mentin correlates well with the presence of numerous 10 nm cytoplasmic filaments as observed by electron mi croscopy. In our case, coarse, dark brown pigment granules were noted within the cytoplasm of several epithelial cells on slides stained with S-1 00 protein. These pigment granules are large and histopathologically resemble those of the retinal pigment epithelium. This finding supports the the ory of pathogenesis provided by Tripathi et al, 2 whereby primitive neuroectodermal cells, in the region ofthe patent embryonic choroidal fissure of the optic vesicle, may be come entrapped among the migrating cells derived from the lens placode or stalk. We also learned of an unpub lished case of phakomatous choristoma, which involved the right lower lid of a 6-month-old boy, displaying similar melanotic pigmentation of some of the epithelial cells (personal communication; Pearl S. Rosenbaum, MD, Norman C. Charles, MD). In the latter case, the pigment granules stained positive for melanin and negative for iron. Phakomatous choristoma of the eyelid should be in cluded in the clinical differential diagnosis of congenital tumors involving the nasal aspect of the lower lid.
References 1. Zimmerman LE. Phakomatous choristoma of the eyelid, a tumor of lenticular anlage. Am J Ophthalmol 1971 ;71: 169 77. 2. Tripathi RC, Tripathi BJ, Ringus J. Phakomatous choris toma of the lower eyelid with psammoma body formation. A light and electron microscopic study. Ophthalmology 1981 ;88: 1198-1206.
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Volume 99, Number 12, December 1992
3. McMahon RT, Font RL, McLean IW. Phakomatous chor istoma ·of eyelid. Electron microscopical confirmation of lenticular derivation. Arch Ophthalmol 1976;94: 1778-81. 4. Filipic M, Silva M. Phakomatous choristoma of the eyelid. Arch Ophthalmol 1972;88: 172-5. 5. Greer CH. Phakomatous choristoma in the eyelid. Aust J Ophthalmol 1975;3:106-7. 6. Baggesen LH, Jensen OA. Phakomatous choristoma oflower eyelid: a lenticular anlage tumour. Ophthalmologica 1977;175:231-5.
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7. Sinclair-Smith CC, Emms M, Morris HB. Phakomatous choristoma of the lower eyelid. A light and ultrastructural study. Arch Pathol Lab Med 1989;113:1175-7. 8. Eustis HS, Karcioglu ZA, Dharma S, Hoda S. Phakomatous choristoma: clinical, histopathologic, and ultrastructural findings in a 4-month-old boy. J Pediatr Ophthalmol Stra bismus 1990;27:208-11. 9. Bloemendal H. Disorganization of membranes and abnor mal intermediate filament assembly lead to cataract. Invest Ophthalmol Vis Sci 1991 ;32:445-55.
