Tumors of the Conjunctiva






Definition


Spectrum of malignant and benign neoplasms, choristomas, and hamartomas arising from or occurring within the conjunctiva, and nonneoplastic epibulbar tumors frequently misdiagnosed clinically as a conjunctival malignant neoplasm.




Key Features





  • Solid mass or discrete lesion of conjunctiva.



  • Wide spectrum of color, texture, and size of tumor and associated features.



  • Substantial differences in age at onset and clinical behavior after detection.





Conjunctival Malignant Neoplasms


A conjunctival malignant neoplasm is a tumor (three-dimensional mass) composed of cancer cells involving the conjunctival epithelium, the stroma, or both. The lesions mentioned in this section are all malignant neoplasms (cancerous tumors) and neoplasias of the conjunctiva. There are three principal categories of malignant neoplasms and neoplasias of the conjunctiva: (1) ocular surface squamous neoplasms and neoplasias (squamous cell carcinoma and its variants), (2) conjunctival melanoma, and (3) conjunctival lymphoma. Several other uncommon but clinically important conjunctival neoplasms will also be mentioned.


Ocular Surface Squamous Neoplasia


The term ocular surface squamous neoplasia (OSSN) encompasses a number of related nonmelanocytic cancers that arise within the epithelium of the conjunctiva, cornea, or both. These cancers range from conjunctival and corneal intraepithelial neoplasia (CIN) (essentially carcinoma in situ within the ocular surface epithelium) to nodular squamous cell carcinoma and variants thereof, including mucoepidermoid carcinoma.


Conjunctival/corneal intraepithelial neoplasia is a localized or diffuse replacement of normal conjunctival or corneal epithelium by malignant cells derived from the stratified squamous epithelium. CIN becomes evident clinically when it involves the corneal epithelium and produces a translucent whitening or graying of the involved portions of that epithelium ( Fig. 4.8.1 ). The lesion can cause substantial impairment of visual acuity if it involves the central cornea. When malignant epithelial cells involve only a portion of the thickness of the epithelium pathologically, the condition is called conjunctival or corneal squamous epithelial dysplasia. When neoplastic epithelial cells replace full-thickness conjunctival epithelium but do not invade the substantia propria, the condition is referred to as squamous cell carcinoma in situ . Most ocular tumor specialists advise excision of conjunctival lesions suspected of being ocular surface squamous neoplasms, and surgical scraping of abnormal appearing corneal epithelium suspected of being corneal intraepithelial neoplasia with submission of the excised specimens to pathology to confirm or rule out the clinical diagnosis before initiating therapies such as topical interferon therapy or topical chemotherapy (see “ Management of Conjunctival Tumors Suspected of Being Malignant Neoplasms or Neoplasias ” below).




Fig. 4.8.1


Conjunctival and Corneal Intraepithelial Neoplasia (CIN).

The corneal epithelium is thickened and translucent in the medial and superomedial portions of the cornea.


Squamous cell carcinoma of the conjunctiva is a malignant neoplasm of the stratified squamous epithelium of the conjunctiva. It appears as a hypervascularized epibulbar tumor that is located most frequently at the limbus medially or temporally. Such tumors occur in three principal clinical patterns. The leukoplakic tumor ( Fig. 4.8.2 ) is characterized by hard, white accumulation of abnormally keratinized conjunctival epithelium overlying the tumor proper. The gelatinous tumor ( Fig. 4.8.3 ) appears as a translucent nodule fed and drained by prominent dilated epibulbar blood vessels. The papillary tumor ( Fig. 4.8.4 ) appears as a pink to reddish mass that exhibits prominent vascular loops internally on slit-lamp biomicroscopy. Many larger tumors exhibit more than one or these clinical patterns ( Fig. 4.8.5 ). Some larger tumors also exhibit ulceration or even intracorneal or intraocular invasion that can be determined by slit-lamp biomicroscopy or ultrasound biomicroscopy (UBM). Aggressive and neglected tumors can invade the orbit and extend partially around the eye, a circumstance that may necessitate exenteration of the orbit.




Fig. 4.8.2


Leukoplakic Squamous Cell Carcinoma of Conjunctiva.

The discrete white hyperkeratotic limbal plaque is associated with prominent conjunctival blood vessels.



Fig. 4.8.3


Papillomatous Squamous Cell Carcinoma of Conjunctiva.

The pink limbal tumor contains multiple fine intralesional corkscrew blood vessels and is associated with dilated afferent and efferent conjunctival blood vessels.



Fig. 4.8.4


Gelatinous Squamous Cell Carcinoma of Conjunctiva.

The translucent limbal mass is associated with dilated afferent and efferent conjunctival blood vessels.



Fig. 4.8.5


Invasive Squamous Cell Carcinoma of Conjunctiva Exhibiting Leukoplakic, Papillary and Gelatinous Components Plus Central Ulceration.

Note blood within the corneal stroma at the pupillary margin of the tumor.


Mucoepidermoid carcinoma ( Fig. 4.8.6 ) is a particularly aggressive form of OSSN that has a strong tendency to recur following attempted excision, invade the eye wall, and invade the orbit. It resembles conventional squamous cell carcinoma quite closely clinically and on routine hematoxylin and eosin–stained microslides but can be distinguished by the presence of prominent goblet cells containing mucin (revealed by stains, such as Alcian blue and mucicarmine) and positive immunoreactivity to immunostain CK7. Because of its aggressively invasive behavior, this ocular surface squamous neoplasm ultimately prompts exenteration in many cases.




Fig. 4.8.6


Mucoepidermoid Carcinoma of Conjunctiva.

This tumor resembles a papillary squamous cell carcinoma near the limbus but has a nodular subepithelial portion extending posteriorly.


Squamous cell carcinoma of the conjunctiva and its variants are the most common primary conjunctival malignant neoplasms encountered in clinical practice. The average annual incidence of squamous cell carcinoma of the conjunctival across all age groups has been estimated to be approximately 17–20 new cases per million persons per year. For a population with an average life expectancy of 70 years, this average annual incidence translates to a cumulative lifetime incidence of approximately 1 case per 700–850 persons. Most tumors of this category are encountered in persons over age 50 years. Risk factors for occurrence include a history of repeated, intense, sunlight exposure; male gender; outdoor occupations; advanced age; cigarette smoking; a history of squamous cell carcinoma of the skin of the head and neck; blond hair and light complexion; xeroderma pigmentosum; acquired immunodeficiency syndrome (AIDS); and conjunctival infection by human papilloma virus (HPV) types 16 and 18.


Conjunctival Melanoma


Malignant melanoma of the conjunctiva is a cancerous neoplasm that arises from melanocytes that are present normally within the basal layers of the conjunctival epithelium. This form of cancer ranges from a flat patch of acquired conjunctival and corneal intraepithelial melanocytic intraepithelial neoplasia (conjunctival–corneal melanoma in situ, malignant primary acquired melanosis) to nodular epibulbar tumors. Most conjunctival melanomas are dark brown but some appear partially if not entirely amelanotic. The only reliable way to distinguish an amelanotic conjunctival melanoma from squamous cell carcinoma or other amelanotic malignant neoplasm is by pathological analysis of the excised or biopsied tumor.


Primary acquired melanosis (PAM) of the conjunctiva refers to a patch of intraepithelial melanocytic hyperplasia to neoplasia that develops from a previously unaffected region of the conjunctiva in an adult individual ( Fig. 4.8.7 ). Such melanotic conjunctival patches may contain only benign or mildly atypical intraepithelial melanocytes (benign acquired melanosis) or markedly atypical malignant melanoma cells (malignant PAM or PAM with severe atypia). Although larger and more heterogeneously melanotic conjunctival lesions are more likely to contain malignant melanoma cells compared with smaller and more homogeneously melanotic lesions, no reliable clinical way exists to distinguish between benign and malignant PAM. Excision or biopsy of the lesion with pathological analysis of the intraepithelial melanocytes is necessary for its classification as benign PAM versus PAM with severe atypia (intraepithelial melanoma). Nodular conjunctival melanoma frequently develops from patches of malignant PAM. Underlying PAM should be suspected in cases with nodular conjunctival melanoma associated with patchy flat melanotic conjunctiva.




Fig. 4.8.7


Primary Acquired Melanosis of Conjunctiva and Cornea.

The lesion is completely flat within the corneal, limbal, and bulbar conjunctival epithelium.


Nodular conjunctival melanoma appears as a solid epibulbar tumor fed and drained by prominent conjunctival blood vessels ( Fig. 4.8.8 ). Such a tumor can arise de novo (i.e., from conjunctiva that appeared normal prior to the tumor’s development) or from a patch of PAM. As indicated above, most conjunctival melanomas are melanotic (brown); however, some are hypomelanotic or amelanotic ( Fig. 4.8.9 ). The most common location for development of a conjunctival melanoma is at or adjacent to the limbus medially or temporally. Such tumors are less likely to metastasize compared with those that develop in the caruncle or semilunar fold or from the forniceal or palpebral conjunctiva. Conjunctival melanomas that metastasize tend to involve regional lymph nodes (preauricular, parotid, and submandibular) on the ipsilateral side of the head and neck initially. Because of this, clinical evaluation should include palpation of the head and neck looking for enlarged lymph nodes. If lymph node metastasis is suspected clinically, lymph node mapping and excision should be considered in conjunction with initial treatment of the conjunctival tumor.




Fig. 4.8.8


Nodular Melanotic Conjunctival Melanoma at Limbus.

Note dilated conjunctival blood vessels associated with lesion.



Fig. 4.8.9


Conjunctival Melanoma Associated With Primary Acquired Melanosis of Conjunctiva.

The nodular conjunctival tumor adjacent limbus is almost completely amelanotic.


Conjunctival Lymphoma


Conjunctival lymphoma is a form of extranodal non-Hodgkin’s lymphoma that arises within the conjunctival substantia propria. Tumors of this type appear as salmon-colored subepithelial masses ( Fig. 4.8.10 ) that can be unilateral or bilateral and unifocal to multifocal in each affected eye. Pathological analysis of such tumors characteristically shows a monoclonal collection of atypical lymphoid cells that usually are of B-scan lineage. Different histopathological patterns are associated with varying likelihoods of systemic lymphoma ranging from very low (mucosa associated lymphoid tumor [MALT] lymphoma) to reasonably high (diffuse large B-cell lymphoma and mantel cell lymphoma). Because of this, histopathological analysis of a biopsy specimen from such a tumor always is appropriate to assess prognosis and develop a management plan. The most common current treatment for isolated low-grade conjunctival lymphoma is low-dose fractionated external beam radiation therapy with shielding of the cornea and lens.




Fig. 4.8.10


Malignant Lymphoma of Conjunctiva.

The tumor is a lumpy, pink, ridge-like mass involving inferior bulbar and forniceal conjunctiva.


In addition to these three most common conjunctival malignant neoplasms, readers should be familiar with uncommon conjunctival malignant neoplasms described below.


Conjunctival Kaposi’s sarcoma is a malignant neoplasm that arises from blood vessels and possibly other tissue elements within the conjunctival stroma. It occurs predominantly in individuals with AIDS or other forms of systemic immunosuppression. The tumor characteristically appears as a dark red, frequently hemorrhagic, conjunctival mass ( Fig. 4.8.11 ) that grows rapidly if untreated. Since introduction of therapeutic regimens that control many of the systemic features of human immunodeficiency virus (HIV) infection, such lesions are much less common than they were several decades ago.




Fig. 4.8.11


Kaposi’s Sarcoma of Conjunctiva.

Note the intensely red color of the tumor and presence of associated subconjunctival blood. This patient had underlying acquired immunodeficiency syndrome (AIDS).


Sebaceous cell carcinoma ( Fig. 4.8.12 ) is a malignant neoplasm that arises from the meibomian glands in the tarsal conjunctiva or the Zeis glands associated with the cilia at the lid margins. It frequently is misdiagnosed as chronic blepharoconjunctivitis and treated as such for weeks to months before the correct diagnosis is suspected and confirmed pathologically. This form of ocular surface cancer has a strong tendency to involve the conjunctival epithelium diffusely (pagetoid spread), a feature that makes it extremely difficult to eradicate surgically. Histopathological analysis of a tumor specimen is the only reliable way to distinguish sebaceous carcinoma from squamous cell carcinoma and its variants.




Fig. 4.8.12


Sebaceous Carcinoma of Conjunctiva.

The tumor replaces semilunar fold and caruncle and involves much of the palpebral conjunctiva and lid margin of the lower eyelid.


Rhabdomyosarcoma is a malignant neoplasm that may arise from previously normal muscle cells. Primary orbital rhabdomyosarcoma is much more common than primary conjunctival rhabdomyosarcoma. Primary conjunctival rhabdomyosarcoma usually appears as a rapidly enlarging pale pink to tan tumor within the conjunctival substantia propria ( Fig. 4.8.13 ). The tumor usually develops during the first 2 decades of life. Biopsy of the tumor with pathological analysis of the specimen is essential for prompt diagnosis and successful treatment. Treatment usually consists of debulking of the tumor followed by several cycles of systemic chemotherapy and orbital external beam radiation therapy.




Fig. 4.8.13


Rhabdomyosarcoma of Conjunctiva and Orbit Presenting as Epibulbar Tumor.

The tumor appears as a pink mass arising from the superior fornix.


Leukemic conjunctival tumors of the substantial propria develop in some patients with leukemia. Tumors of this type ( Fig. 4.8.14 ) appear similar to conjunctival lymphomas. They are extremely uncommon but can be the presenting sign of leukemia in some individuals, and the initial manifestation of relapse of some previously treated leukemias.




Fig. 4.8.14


Leukemic Tumor of Conjunctiva.

The tumor is a well-defined, reddish-pink, ridge-like mass involving the superior fornix.




Ocular Surface Squamous Neoplasia


The term ocular surface squamous neoplasia (OSSN) encompasses a number of related nonmelanocytic cancers that arise within the epithelium of the conjunctiva, cornea, or both. These cancers range from conjunctival and corneal intraepithelial neoplasia (CIN) (essentially carcinoma in situ within the ocular surface epithelium) to nodular squamous cell carcinoma and variants thereof, including mucoepidermoid carcinoma.


Conjunctival/corneal intraepithelial neoplasia is a localized or diffuse replacement of normal conjunctival or corneal epithelium by malignant cells derived from the stratified squamous epithelium. CIN becomes evident clinically when it involves the corneal epithelium and produces a translucent whitening or graying of the involved portions of that epithelium ( Fig. 4.8.1 ). The lesion can cause substantial impairment of visual acuity if it involves the central cornea. When malignant epithelial cells involve only a portion of the thickness of the epithelium pathologically, the condition is called conjunctival or corneal squamous epithelial dysplasia. When neoplastic epithelial cells replace full-thickness conjunctival epithelium but do not invade the substantia propria, the condition is referred to as squamous cell carcinoma in situ . Most ocular tumor specialists advise excision of conjunctival lesions suspected of being ocular surface squamous neoplasms, and surgical scraping of abnormal appearing corneal epithelium suspected of being corneal intraepithelial neoplasia with submission of the excised specimens to pathology to confirm or rule out the clinical diagnosis before initiating therapies such as topical interferon therapy or topical chemotherapy (see “ Management of Conjunctival Tumors Suspected of Being Malignant Neoplasms or Neoplasias ” below).




Fig. 4.8.1


Conjunctival and Corneal Intraepithelial Neoplasia (CIN).

The corneal epithelium is thickened and translucent in the medial and superomedial portions of the cornea.


Squamous cell carcinoma of the conjunctiva is a malignant neoplasm of the stratified squamous epithelium of the conjunctiva. It appears as a hypervascularized epibulbar tumor that is located most frequently at the limbus medially or temporally. Such tumors occur in three principal clinical patterns. The leukoplakic tumor ( Fig. 4.8.2 ) is characterized by hard, white accumulation of abnormally keratinized conjunctival epithelium overlying the tumor proper. The gelatinous tumor ( Fig. 4.8.3 ) appears as a translucent nodule fed and drained by prominent dilated epibulbar blood vessels. The papillary tumor ( Fig. 4.8.4 ) appears as a pink to reddish mass that exhibits prominent vascular loops internally on slit-lamp biomicroscopy. Many larger tumors exhibit more than one or these clinical patterns ( Fig. 4.8.5 ). Some larger tumors also exhibit ulceration or even intracorneal or intraocular invasion that can be determined by slit-lamp biomicroscopy or ultrasound biomicroscopy (UBM). Aggressive and neglected tumors can invade the orbit and extend partially around the eye, a circumstance that may necessitate exenteration of the orbit.




Fig. 4.8.2


Leukoplakic Squamous Cell Carcinoma of Conjunctiva.

The discrete white hyperkeratotic limbal plaque is associated with prominent conjunctival blood vessels.



Fig. 4.8.3


Papillomatous Squamous Cell Carcinoma of Conjunctiva.

The pink limbal tumor contains multiple fine intralesional corkscrew blood vessels and is associated with dilated afferent and efferent conjunctival blood vessels.



Fig. 4.8.4


Gelatinous Squamous Cell Carcinoma of Conjunctiva.

The translucent limbal mass is associated with dilated afferent and efferent conjunctival blood vessels.



Fig. 4.8.5


Invasive Squamous Cell Carcinoma of Conjunctiva Exhibiting Leukoplakic, Papillary and Gelatinous Components Plus Central Ulceration.

Note blood within the corneal stroma at the pupillary margin of the tumor.


Mucoepidermoid carcinoma ( Fig. 4.8.6 ) is a particularly aggressive form of OSSN that has a strong tendency to recur following attempted excision, invade the eye wall, and invade the orbit. It resembles conventional squamous cell carcinoma quite closely clinically and on routine hematoxylin and eosin–stained microslides but can be distinguished by the presence of prominent goblet cells containing mucin (revealed by stains, such as Alcian blue and mucicarmine) and positive immunoreactivity to immunostain CK7. Because of its aggressively invasive behavior, this ocular surface squamous neoplasm ultimately prompts exenteration in many cases.




Fig. 4.8.6


Mucoepidermoid Carcinoma of Conjunctiva.

This tumor resembles a papillary squamous cell carcinoma near the limbus but has a nodular subepithelial portion extending posteriorly.


Squamous cell carcinoma of the conjunctiva and its variants are the most common primary conjunctival malignant neoplasms encountered in clinical practice. The average annual incidence of squamous cell carcinoma of the conjunctival across all age groups has been estimated to be approximately 17–20 new cases per million persons per year. For a population with an average life expectancy of 70 years, this average annual incidence translates to a cumulative lifetime incidence of approximately 1 case per 700–850 persons. Most tumors of this category are encountered in persons over age 50 years. Risk factors for occurrence include a history of repeated, intense, sunlight exposure; male gender; outdoor occupations; advanced age; cigarette smoking; a history of squamous cell carcinoma of the skin of the head and neck; blond hair and light complexion; xeroderma pigmentosum; acquired immunodeficiency syndrome (AIDS); and conjunctival infection by human papilloma virus (HPV) types 16 and 18.




Conjunctival Melanoma


Malignant melanoma of the conjunctiva is a cancerous neoplasm that arises from melanocytes that are present normally within the basal layers of the conjunctival epithelium. This form of cancer ranges from a flat patch of acquired conjunctival and corneal intraepithelial melanocytic intraepithelial neoplasia (conjunctival–corneal melanoma in situ, malignant primary acquired melanosis) to nodular epibulbar tumors. Most conjunctival melanomas are dark brown but some appear partially if not entirely amelanotic. The only reliable way to distinguish an amelanotic conjunctival melanoma from squamous cell carcinoma or other amelanotic malignant neoplasm is by pathological analysis of the excised or biopsied tumor.


Primary acquired melanosis (PAM) of the conjunctiva refers to a patch of intraepithelial melanocytic hyperplasia to neoplasia that develops from a previously unaffected region of the conjunctiva in an adult individual ( Fig. 4.8.7 ). Such melanotic conjunctival patches may contain only benign or mildly atypical intraepithelial melanocytes (benign acquired melanosis) or markedly atypical malignant melanoma cells (malignant PAM or PAM with severe atypia). Although larger and more heterogeneously melanotic conjunctival lesions are more likely to contain malignant melanoma cells compared with smaller and more homogeneously melanotic lesions, no reliable clinical way exists to distinguish between benign and malignant PAM. Excision or biopsy of the lesion with pathological analysis of the intraepithelial melanocytes is necessary for its classification as benign PAM versus PAM with severe atypia (intraepithelial melanoma). Nodular conjunctival melanoma frequently develops from patches of malignant PAM. Underlying PAM should be suspected in cases with nodular conjunctival melanoma associated with patchy flat melanotic conjunctiva.




Fig. 4.8.7


Primary Acquired Melanosis of Conjunctiva and Cornea.

The lesion is completely flat within the corneal, limbal, and bulbar conjunctival epithelium.


Nodular conjunctival melanoma appears as a solid epibulbar tumor fed and drained by prominent conjunctival blood vessels ( Fig. 4.8.8 ). Such a tumor can arise de novo (i.e., from conjunctiva that appeared normal prior to the tumor’s development) or from a patch of PAM. As indicated above, most conjunctival melanomas are melanotic (brown); however, some are hypomelanotic or amelanotic ( Fig. 4.8.9 ). The most common location for development of a conjunctival melanoma is at or adjacent to the limbus medially or temporally. Such tumors are less likely to metastasize compared with those that develop in the caruncle or semilunar fold or from the forniceal or palpebral conjunctiva. Conjunctival melanomas that metastasize tend to involve regional lymph nodes (preauricular, parotid, and submandibular) on the ipsilateral side of the head and neck initially. Because of this, clinical evaluation should include palpation of the head and neck looking for enlarged lymph nodes. If lymph node metastasis is suspected clinically, lymph node mapping and excision should be considered in conjunction with initial treatment of the conjunctival tumor.




Fig. 4.8.8


Nodular Melanotic Conjunctival Melanoma at Limbus.

Note dilated conjunctival blood vessels associated with lesion.



Fig. 4.8.9


Conjunctival Melanoma Associated With Primary Acquired Melanosis of Conjunctiva.

The nodular conjunctival tumor adjacent limbus is almost completely amelanotic.




Conjunctival Lymphoma


Conjunctival lymphoma is a form of extranodal non-Hodgkin’s lymphoma that arises within the conjunctival substantia propria. Tumors of this type appear as salmon-colored subepithelial masses ( Fig. 4.8.10 ) that can be unilateral or bilateral and unifocal to multifocal in each affected eye. Pathological analysis of such tumors characteristically shows a monoclonal collection of atypical lymphoid cells that usually are of B-scan lineage. Different histopathological patterns are associated with varying likelihoods of systemic lymphoma ranging from very low (mucosa associated lymphoid tumor [MALT] lymphoma) to reasonably high (diffuse large B-cell lymphoma and mantel cell lymphoma). Because of this, histopathological analysis of a biopsy specimen from such a tumor always is appropriate to assess prognosis and develop a management plan. The most common current treatment for isolated low-grade conjunctival lymphoma is low-dose fractionated external beam radiation therapy with shielding of the cornea and lens.




Fig. 4.8.10


Malignant Lymphoma of Conjunctiva.

The tumor is a lumpy, pink, ridge-like mass involving inferior bulbar and forniceal conjunctiva.


In addition to these three most common conjunctival malignant neoplasms, readers should be familiar with uncommon conjunctival malignant neoplasms described below.


Conjunctival Kaposi’s sarcoma is a malignant neoplasm that arises from blood vessels and possibly other tissue elements within the conjunctival stroma. It occurs predominantly in individuals with AIDS or other forms of systemic immunosuppression. The tumor characteristically appears as a dark red, frequently hemorrhagic, conjunctival mass ( Fig. 4.8.11 ) that grows rapidly if untreated. Since introduction of therapeutic regimens that control many of the systemic features of human immunodeficiency virus (HIV) infection, such lesions are much less common than they were several decades ago.




Fig. 4.8.11


Kaposi’s Sarcoma of Conjunctiva.

Note the intensely red color of the tumor and presence of associated subconjunctival blood. This patient had underlying acquired immunodeficiency syndrome (AIDS).


Sebaceous cell carcinoma ( Fig. 4.8.12 ) is a malignant neoplasm that arises from the meibomian glands in the tarsal conjunctiva or the Zeis glands associated with the cilia at the lid margins. It frequently is misdiagnosed as chronic blepharoconjunctivitis and treated as such for weeks to months before the correct diagnosis is suspected and confirmed pathologically. This form of ocular surface cancer has a strong tendency to involve the conjunctival epithelium diffusely (pagetoid spread), a feature that makes it extremely difficult to eradicate surgically. Histopathological analysis of a tumor specimen is the only reliable way to distinguish sebaceous carcinoma from squamous cell carcinoma and its variants.




Fig. 4.8.12


Sebaceous Carcinoma of Conjunctiva.

The tumor replaces semilunar fold and caruncle and involves much of the palpebral conjunctiva and lid margin of the lower eyelid.


Rhabdomyosarcoma is a malignant neoplasm that may arise from previously normal muscle cells. Primary orbital rhabdomyosarcoma is much more common than primary conjunctival rhabdomyosarcoma. Primary conjunctival rhabdomyosarcoma usually appears as a rapidly enlarging pale pink to tan tumor within the conjunctival substantia propria ( Fig. 4.8.13 ). The tumor usually develops during the first 2 decades of life. Biopsy of the tumor with pathological analysis of the specimen is essential for prompt diagnosis and successful treatment. Treatment usually consists of debulking of the tumor followed by several cycles of systemic chemotherapy and orbital external beam radiation therapy.




Fig. 4.8.13


Rhabdomyosarcoma of Conjunctiva and Orbit Presenting as Epibulbar Tumor.

The tumor appears as a pink mass arising from the superior fornix.


Leukemic conjunctival tumors of the substantial propria develop in some patients with leukemia. Tumors of this type ( Fig. 4.8.14 ) appear similar to conjunctival lymphomas. They are extremely uncommon but can be the presenting sign of leukemia in some individuals, and the initial manifestation of relapse of some previously treated leukemias.




Fig. 4.8.14


Leukemic Tumor of Conjunctiva.

The tumor is a well-defined, reddish-pink, ridge-like mass involving the superior fornix.




Benign Conjunctival Neoplasms and Neoplasias


A benign conjunctival neoplasm is an acquired tumor composed of noncancerous cells and develops within previously normal-appearing conjunctival epithelium, substantia propria, or both. A conjunctival choristoma is a congenital tumor of the conjunctiva composed of noncancerous cells that are not normally present within that tissue. A conjunctival hamartoma is a congenital tumor of the conjunctiva composed of noncancerous cells that are present normally in that tissue but are present in excessive number and with atypical or disorganized tissue architecture. Although tumors of the latter two types are not precisely “neoplasms,” they are lumped together with benign neoplasms and neoplasias in this section.


Conjunctival Nevus


The conjunctival nevus is a benign neoplasm consisting of mildly atypical but noncancerous melanocytes that arose from normal conjunctival melanocytes within the basal layers of the conjunctival epithelium. This tumor is, by far, the most common primary ocular neoplasm encountered in clinical practice. The typical lesion is not present at birth in most patients but develops later in life (most frequently within the first 2 decades of life) from previously normal appearing conjunctiva, typically at the limbus medially or temporally. The lesion appears as a discrete brown to tan conjunctival tumor in most patients ( Fig. 4.8.15 ) but is completely amelanotic and translucent in some persons. The lesion is typically not associated with any prominent dilated tortuous epibulbar feeder and drainer blood vessels. On slit-lamp biomicroscopy, numerous intraepithelial microcysts commonly are evident within such a lesion. Limited slow enlargement and darkening of such lesions is frequently reported by the parents of the affected child. Such lesions appear to have very limited malignant potential.




Fig. 4.8.15


Conjunctival Nevus.

The tumor is partly melanotic but predominantly tan and associated with moderately prominent conjunctival blood vessels.


Benign Acquired Melanosis of Conjunctiva


Many patients (particularly those of races with dark pigmentation) develop progressive acquired conjunctival melanosis, almost always bilaterally and most frequently in the limbal region ( Fig. 4.8.16 ), as they age. In some patients, the melanosis also involves the bulbar, forniceal, and even palpebral conjunctiva in patchy fashion. This form of acquired conjunctival melanosis is almost always benign histopathologically and rarely gives rise to conjunctival melanoma.




Fig. 4.8.16


Benign Acquired Melanosis of Conjunctiva.

The bulbar conjunctival melanosis is more prominent OS (left eye) than OD (right eye) but was evident along the limbus OU (both eyes) symmetrically in this dark-skinned individual.


Conjunctival Hemangioma


A conjunctival hemangioma is a benign blood vessel tumor of the conjunctival stroma. In many patients, the lesion is present at birth. In such patients, the lesion should probably be regarded as a hamartoma. Small lesions of this type are usually asymptomatic and can be left alone. In contrast, complex epibulbar hemangiomas ( Fig. 4.8.17 ) can be objectionable cosmetically. Repeated sessions of cryotherapy often are quite effective in reducing the size and decreasing the brightness of such lesions. In the authors’ experience, attempts to excise such lesions or treat them with sclerosing solutions usually are unsuccessful and frequently make the situation worse. Fortunately, such tumors have limited if any malignant potential.




Fig. 4.8.17


Conjunctival and Intrascleral Hemangioma.

This congenital vascular tumor is composed of bright red superficial blood vessels and darker intrascleral blood vessels.


Conjunctival Squamous Papilloma


A benign squamous papilloma of the conjunctiva is a neoplasm composed of nonmalignant vascularized fronds of subepithelial connective tissue covered by intact stratified squamous epithelium ( Fig. 4.8.18 ). It may be columnar or sessile in shape. Many lesions of this type that have been evaluated microbiologically have been found to harbor HPV type 6 or 11, and others have been linked to other HPV subtypes.




Fig. 4.8.18


Squamous Papilloma of Conjunctiva.

The tumor is a pink columnar tumor arising from the peripheral bulbar conjunctiva.


Conjunctival Lymphangioma


A conjunctival lymphangioma ( Fig. 4.8.19 ) is an ill-defined tumor of the conjunctival substania propria composed of mature lymphatic channels in excessive amounts. In most cases, the conjunctival tumor is the anterior and, therefore, visible portion of a more extensive orbital lymphangioma. Such tumors are probably congenital in many cases (in which case they should be categorized as conjunctival hamartomas) but frequently do not show up until late in childhood to early adult years, typically in association with an upper respiratory or sinus infection. The lesion may enlarge abruptly and sometimes fills with blood. Piecemeal excision of the lesion, supplemented by cryotherapy, frequently is performed to treat prominent tumors of this type.




Fig. 4.8.19


Lymphangioma of Conjunctiva.

The limited bulbar conjunctival tumor consists of dilated lymphatic channels filled with yellow-tinted clear fluid.


Conjunctival Choristomas


Conjunctival choristomas are benign congenital tumors composed of nonmalignant cells and tissues that do not occur normally in the conjunctiva. The cells and tissues that comprise the tumor are generally arranged haphazardly. The tumor frequently contains both mesodermal and ectodermal elements, in which case it is referred to as a dermoid tumor . Because many of the conjunctival tumors categorized as choristomas are not detected until late childhood to early adulthood, their congenital nature frequently cannot be verified. Several discrete subtypes of conjunctival choristomas exist, including those discussed below.


Limbal Dermoid


The limbal dermoid is the most frequently encountered type of conjunctival choristoma. This lesion is present at birth and appears as an off-white to fleshy tumor overlying the corneoscleral limbus, most commonly inferotemporally ( Fig. 4.8.20 ). The typical tumor contains both mesodermal elements (most commonly fibroblasts, hair follicles, and fat) and ectodermal elements (epithelial cells). Such lesions are a typical feature of Goldenhar’s syndrome and often are bilateral in individuals with this disorder. Excision of the lesion by lamellar or penetrating keratoplasty can be performed if the lesion is objectionable cosmetically, causing induced astigmatism with potential for amblyopia.




Fig. 4.8.20


Limbal Dermoid Tumor.

The tumor is an off-white, discoid mass straddling the limbus inferotemporally.


Conjunctival Solid Dermoid


The conjunctival solid dermoid is a nodular nonlimbal conjunctival tumor composed of benign mesodermal and ectodermal cells. A tumor of this type is generally heterogeneously pigmented and frequently exhibits prominent hair shafts protruding from its surface ( Fig. 4.8.21 ). Such tumors are commonly not noted until late childhood or early adolescence, and the timing of development of these lesions is unknown. Treatment is simple excision.




Fig. 4.8.21


Solid Dermoid Tumor of Conjunctiva.

The tumor is heterogeneously pigmented and contains several protruding hair shafts.


Conjunctival Dermolipoma


The conjunctival dermolipoma is a soft tissue tumor composed almost exclusively of fat within the substantia propria of the conjunctiva, almost always superotemporally. The tumor appears similar to a prolapsed orbital fat pad that develops in some older adults ( Fig. 4.8.22 ); true conjunctival dermolipomas, however, tend to become apparent much earlier in life.


Oct 3, 2019 | Posted by in OPHTHALMOLOGY | Comments Off on Tumors of the Conjunctiva
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