Orbital Teratoma

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Article initiated by:

Simanta Khadka, MD

All contributors:

Simanta Khadka, MD, Kelvin Chong, MB ChB FHKAM(Ophth), Jill Wells, MD, Michael T Yen, MD, Preeti Thyparampil, MD, Cat Nguyen Burkat, MD FACS, Jake Uy Sebastian, MD (DPBO)

Assigned editor:

Kelvin Chong, MB ChB FHKAM(Ophth)

Review:

Assigned status Up to Date

 by Kelvin Chong, MB ChB FHKAM(Ophth) on August 14, 2024.

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Contributing Editors:	add

Orbital Teratoma

DiseasesDB

3604

ICD-10

[1]31.6

MeSH

D013724

Orbital Teratoma

Disease Entity

Diagnosis Code from ICD-10 Version 2017 : D31.6 Short Description: Benign neoplasm of unspecified site of orbit applicable to

• Benign neoplasm of connective tissue of orbit.
• Benign neoplasm of extraocular muscle.
• Benign neoplasm of peripheral nerves of orbit.
• Benign neoplasm of retrobulbar tissue.
• Benign neoplasm of retro-ocular tissue.

Introduction

A teratoma is a unilateral, congenital neoplasm containing structures originating from all three germinal cell layers, and it exhibits a pattern of growth foreign to its anatomic site. The orbit is a rare, but typical, location in which primary extragonadal germ cell tumors arise.

Fig.1: Frontal view of a huge orbital teratoma with compressed eyeball in a two day old female neonate. © Simanta Khadka 2017

The origin of teratoma has been derived from Greek word “Teratos” and “Oma”. The literal meaning of which accounts to teratos meaning unusual occurrence or phenomenon, monster and oma meaning complete set of, or a condition.

Historical Reporting

Holmes first reported an orbital tumor compatible with a teratoma in 1863, but due to the primitive histopathological methods available at that time, Broer and Weigert are credited with describing the first unquestionable orbital teratoma in 1876. Seven years later, Lawson reported an orbital teratoma that extended into the intracranial cavity, and in 1924 Prym briefly described an intracranial teratoma extending into the orbit.

Etiopathogenesis

Teratomas, the most common of orbital germ cell tumors, probably arise from pluripotential embryonic stem cells that are carried to the orbit by blood circulation and escape regulatory influences, or from primordial germ cells that aim toward the pineal gland, even though other theories have also been proposed. Orbital teratomas reported so far have been unilateral, and tumors cited as bilateral seem to have been limbal dermoids.

Epidemiology

Teratomas account for 6.6% of childhood tumors, most commonly occurring in the testes, ovaries, and retroperitoneum; the orbit is a very rare site. A review of the literature showed that females are affected more than males in an approximately 2:1 ratio, with a propensity of the tumor to occur more frequently in the left than in the right orbit. Most cases reported in the literature are cytologically benign, however in some cases, tumors may grow rapidly, and severe complications may ensue.

Classification

Classification of Orbital Teratomas by Mizuo and Duke-Elder;

1. A complete fetus implanted in the orbit (orbitopagus parasiticus).
2. A portion of a second fetus in the orbit.
3. A tumor consisting of all three germinal layers.
4. Tumors containing representatives of two germinal cell layers only.
5. Tumors containing representatives of one layer only (dermoid cysts, osteomata, chondromata, etc.).

This classical system of classification has been modified by Damato where the last sub-category was removed and it includes only four categories.

Diagnosis

Clinical presentation

Extreme unilateral proptosis in an otherwise healthy newborn with marked stretching of the eyelids over a tense, fluctuating mass, elongation of the palpebral fissure, normally developed eye that may exhibit degenerative changes secondary to the displacement by the teratoma, and transillumination of all or part of the orbital mass. Most tumors are intraconal and stretch the four recti, which results in a quadrangular shape and axial proptosis. The eye might be buried within the tumor itself, and only the cornea or a narrow rim of the sclera visible. Exposure keratopathy, ulceration, keratoiritis, and even spontaneous perforation occur secondarily. The proptosis may be axial or vertical.

Fig.2: Side view of the mass after antiseptic painting on OT table.© Simanta Khadka 2017

The eye is usually normally formed, but displaced superiorly and forward. In rare cases there is no organized eye, with only remnants of ocular tissues being present. The persistent enlargement of this neoplasm is attributed to mucus secretion from the embryonic intestinal tissue. The optic nerve may be encased or adherent to the tumor, leading to secondary atrophy and poor pupil reaction.Commonly the eye is normally developed but often vision is not preserved either due to optic atrophy or corneal exposure, probably to the amniotic fluid.

Other features include; no family history of congenital deformities with non-consanguineous parents and normal siblings, normal pregnancy and delivery, no history of teratogenic influences to the mother.

Radiological Finding

Upon imaging, benign orbital teratomas usually reveals multiloculated, cystic masses with an admixture of tissues including calcification, fat and ossification. In some instances, CT would show a well-defined mass with focal areas of calcifications without bony erosion. Orbital MRI demonstrates variable signal intensities, but is valuable to ascertain intracranial involvement. Radiologic examinations are essential for a prompt diagnosis: MRI is the criterion standard and is usually correlated with a CT scan.

Fig.3: CT scan showing heterogenous mass compressing the globe and expansion of left orbit. © Simanta Khadka 2017

Differential diagnosis

The differential diagnosis of orbital teratoma includes microphthalmos with cyst, dermoid cyst, epidermoid inclusion cysts, hemangioma, lymphangioma, cephalocele, neuroblastoma, rhabdomyosarcoma and retinoblastoma. Microphthalmos with cyst is distinguished on the basis of a small globe in conjunction with a communicating channel between it and an attached cyst.Dermoid cysts are unilocular and have a single fat-fluid level. Epidermoid inclusion cysts, probably because of their proteinaceous contents, are usually similar in appearance to water or cerebral spinal fluid on CT. Lymphangiomas are multilocular, but do not contain fat or calcification. Cephaloceles contain cerebral spinal fluid and generally have adjacent osseous abnormalities, but unlike teratomas and dermoids, cephaloceles do not contain lipid.Rhabdomyosarcoma, neuroblastoma and retinoblastoma should be considered in children presenting after the newborn period. The first two show evidence of bone destruction and the latter intraocular mass lesion or calcification.

Histopathological Findings

Histopathological analysis of representative tissues makes the definite diagnosis of teratoma. Histologically, teratomas are composed of tissues derived from the three germinal layers., The predominant germ cell types observed in orbital teratoma are surface ectoderm producing squamous epithelium-lined cyst, hair follicles, and sweat glands. Neuroectodermal tissues include primitive neural tubes, choroidal plexus, and ganglia. Mesoderm is the next most common cell layer represented by the muscle, bone, cartilage, and fat. Endoderm is the least common and may produce gastrointestinal tissue cysts lined by respiratory-type pseudostratified columnar epithelium. Cystic spaces lined by glandular epithelium are responsible for the rapid enlargement of the lesions.

Fig.4.A: Histopathological section of mature teratoma showing intestinal mucosa. © Simanta Khadka 2017

Fig.4.B: Histopathological section of mature teratoma showing neural elements. © Simanta Khadka 2017

Fig.4.C: Histopathological section of mature teratoma showing lymphoid follicles. © Simanta Khadka 2017

Management

The clinical management of these lesions is unclear, due in part to their low incidence and to an incomplete understanding of their natural history. Complete surgical excision of the tumor is the only acceptable treatment.

Surgery

Early surgery is mandatory to avoid permanent sequelae. The treatment is complete tumor excision with sparing of the eye, if possible. In the past, many surgeons preferred orbital exenteration because of malignant potential. It is hard to recommend a fixed management plan; however, a common agreement in the management objectives should be to save the eye, retain some vision, encourage normal orbitofacial development, and to maintain good cosmetic result.

Fig.5.A: Operative picture of the orbital teratoma after complete separation from the surrounding tissues and showing the intact optic nerve. © Simanta Khadka 2017

Fig.5.B: Operative picture showing compressed eyeball with intact optic nerve after complete excision of the teratoma. © Simanta Khadka 2017

Malignant teratomas and intracranial extension

Most of the orbital teratomas are benign. Only few cases of orbital teratomas with malignant changes have been reported. Histopathological examination revealed malignant sarcomatous changes in these variants. Teratoma is considered malignant when the tissue is embryonal or immature in nature. There is controversy on the diagnostic value of serum alpha-fetoprotein for mature teratomas, especially in the newborn period, being normally high as a result of fetal production. However, elevated serum alpha-fetoprotein levels may signal the presence of regional recurrence or metastatic disease in the setting of malignant teratoma. Usually orbital teratoma is limited within the orbital cavity but there were also reported instances with intracranial involvement termed as orbito-cranial teratomas.

Follow up and prognosis

Orbital teratomas have been known to recur and may undergo malignant degeneration. Therefore, close follow-up is necessary. Follow up is necessary not only to ascertain recurrence but also to encourage normal orbito facial development and maintain cosmesis.

The prognosis of the orbital teratoma is related to several factors including the age, site, and grade of immaturity, and is usually good if complete excision is performed early in neonatal life.

Additional Resources

© Simanta Khadka.

Khadka S, Shrestha GB, Gautam P, Shrestha JB. Orbital Teratoma: A rare congenital tumour. Nepalese Journal of Ophthalmology. 2017 Jun 20;9(1):79-82.