Introduction
Conjunctival myxoma is a benign neoplasm of primitive mesenchyme origin.1 Though, heart is the most common site for myxoma, bone, skin, skeletal muscle, genitourinary system and gastrointestinal tract are other common sites for myxoma. Myxomas are rarely seen in upper respiratory tract, breast, and eyes.2, 3 Conjunctival myxoma are usually covered by conjunctival epithelium and arises from substatntia propria layer of the conjunctiva.4, 5 It can masquerade as conjunctival lymphoma, lymphangioma, amelanotic nevus, amelanotic melanoma, squamous cell carcinoma, lipoma and cyst.6 It can be associated with certain syndromes such as Carney complex and Zollinger–Ellison syndrome.7 Clinically differentiation of conjunctival myxoma from other tumours is difficult and confirmed only by histopathological examination. Conjunctival myxoma usually presents as painless, slow growing mass in the eye. It is removed by complete surgical excision.
Case Report
We report a case of 65 years old female who presented to us with chief complaints of painless swelling in right eye for 5 months which was gradually increasing in size. Patient had slight restriction of movement laterally. It was not associated with redness, pain, discharge, any visual abnormality or trauma. All other systemic examinations were normal. Patient did not have any history of similar complaints in past in either eye. Her other anterior and posterior segment examination was normal. On slit-lamp examination of the right eye a well-circumscribed cystic mass in the temporal conjunctiva was found as seen in Figure 1. Since there was slight restriction of movement temporally so there might be involvement of lateral rectus muscle. Clinically it was diagnosed as right infero-temporal conjunctival cyst. The mass was completely excised under local anaesthesia which measured 9.0 mm x 6.0 mm x 6.0 mm as shown in Figure 2 without traumatising lateral rectus muscle which can be seen in Figure 3 and was sent for histopathological examination. The pathology report showed bland cells without mitotic activity, peripheral areas were more cellular with collagenised capsule and areas of increased vascularity and hypercellularity. Few areas comprised of basophilic matrix with spindle cells with oval nuclei with intracytoplasmic and intranuclear vacuoles with few vascular structures, and reticulin fibres. The diagnosis was confirmed as conjunctival myxoma. Patient was followed for 1 year and did not show any recurrence.
Discussion
Conjunctival myxoma is a rare clinical entity. It can be confused as some other common tumours of conjunctiva such as amelanotic nevus, amelanotic melanoma, dermal nerve sheath myxoma, myxoid neurofibroma, lymphangioma, lymphoma, reactive lymphoid hyperplasia, dermoid, myxoid liposarcoma, spindle cell lipoma etc.8 However, it can be differentiated from other soft tissue tumours by absence of significant cellularity, mitotic figures, or pleomorphic nuclei and by other factors such as the absence of prominent vascular structures, pigmentation, or dense collagen fibres. It can be differentiated from amelanotic nevus or melanoma by the absence of pigmentation or vascular structures and the absence of nests of cells characteristic of melanoma.
Nerve sheath myxomas and myxoid neurofibroma are usually associated with systemic neurofibromatosis and contain dense, wavy collagen structures; prominent, spindly nuclei; and occasional lymphocytes. The tumours are Bodian-positive on staining. Lymphangiomas are vascular, boggy tumours with haemorrhagic and inflammatory components and occur usually in younger individuals.8 Significant lymphocyte population can be seen in Lymphomas and reactive lymphoid hyperplasia. Hence, confirmed diagnosis of conjunctival tumour is based on histopathology report. Though systemic examination is required in young patients and recurrent tumours where it can be associated with other systemic conditions and syndromes.
Treatment of conjunctival myxoma is simple by complete surgical excision with extra excision of tumour free margin to prevent recurrence. There is a rare chance of recurrence which if occurs need further systemic evaluation.
Conclusion
Conjunctival myxomas are rare tumour which can mimic other tumours. Complete excision with histopathological report is required to confirm the diagnosis. Though, it does not require other local or systemic investigation but, in some situations as in young individuals and recurrent cases other systemic investigations are needed to rule out any systemic associations.
